A review of the ant fauna of the Krakatau Islands, Indonesia

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1 Bull. Kitakyushu Mus. Nat. Hist. Hum. Hist., A Ser. review A, 11: of 1 66, the ant March fauna 31, of the 2013 Krakatau Islands, Indonesia 1 A review of the ant fauna of the Krakatau Islands, Indonesia Graduate School of Science and Engineering, Kagoshima University, Kagoshima, Japan (Received October 4, 2012; accepted February 12, 2013) ABSTRACT The ant fauna of the Krakatau Islands, Indonesia is reviewed. All the collection records obtained in five survey periods since the catastrophic eruption in 1883 are presented for each of the four islands of the Krakatau group. In the actual species number was 99, and the colonisation curve was still rising without any indication of reaching an equilibrium species number. Formicinae were earlier colonists at both genus and species level, while Myrmicinae and Ponerinae tended to have arrived later. Nesting biology of ants was also studied. Among the 49 species for which the nesting site was confirmed 74% were found from dead wood and twigs, while 14% from ground surface and in soil. A Leptogenys species adopting fission as colony mutiplication was found in 1982 and All this indicates that the immigration of many species was by rafting on the sea but that dispersal by air also occurred. Early colonsation of pioneer plants with extrafloral nectaries may have been important for the early ant colonisers to survive under poor vegetation. Fifteen tramp species have been so far recorded, of which only one (Pheidole megacepahla) has become extinct. Most turnover events are considered to have occurred in association with vegetation succession. KEY WORDS: Krakatau, recolonisation, ants, equilibrium species number, extinction, dispersal methods, tramp species INTRODUCTION Krakatau, or Krakatoa in English, is a name collectively applied to the four small islands located in the Sunda Straits between Java and Sumatra, Indonesia. This island group, the Krakataus or Krakatau Islands, has attracted many field biologists, especially biogeographers, because it has provided the stage for a natural experiment in studying dynamic island biogeography (e.g., MacArthur and Wilson 1963; Thornton, 1996). After the catastrophic eruptions in 1883 that are said to have terminated almost all biota on the Krakataus, the newly colonising fauna and flora were intensively studied from 1919 until 1933 by K. W. Dammerman and W. M. Docters van Leeuwen to reveal the recolonisation process of plants and animals (Dammerman, 1948; Docters van Leeuwen, 1936). After a break of around 40 years since the cessation of the Asia Pacific War, field surveys on animals were resumed in the 1980s by Japanese and Australian teams, yielding rich information about the animals that had arrived during the long interval. Dammerman s (1948) synthesis entitled The fauna of Krakatau is still the most reliable source of data when analyzing the colonisation process of animals in the earlier phase. The list of animals compiled by him contains a synonymic list, brief description, and collection records (year, island, collector) for each species. Thornton (1996) reviewed the whole process of the colonisation of the Krakataus by animals and plants based on the classical works by Dammerman and Docters van Leeuwen and the results of the surveys made in the 1980s. The ant fauna of the Krakatau Islands has been studied by Jacobson (1909), Dammerman (1948), Wara et al. (2008), Abe et al. (2012), and Yamane (present study). In I collected ants on all the four islands (Rakata, Sertung, Panjang and Anak Krakatau) and on adjacent islands (Sebesi, Sebuku and Legundi) between Krakatau and Sumatra, and also in West Java (Carita) and southern Sumatra (Lampung). This allows us to depict a colonisation curve for ants throughout approximately 123 years after the great eruptions in 1883, which destroyed most of the biota present on the Krakataus before the event. The results of the surveys made in areas surrounding the Krakataus will be reported in a separate paper.

2 2 MATERIALS AND STUDY AREA Materials and Methods Krakatau was visited by Japanese entomologists four times, in the dry season (July/August 1982, August 2005) and wet season (October/November, 1982, December 2006 to January 2007). In 1982 ants were sampled by the late Dr. Takuya Abe, a famous specialist of termite ecology (but also having rich experience in ant research) (October/November), and myself, then a taxonomist of aculeate wasps (July/August). We spent a lot of time for sampling ants, and the data should have reasonable precision. The net duration spent on the collection of aculeate Hymenoptera, including ants, on each island by Yamane was: 33 h 17 min on Rakata, 29 h 35 min on Sertung, 16 h and 30 min on Panjang, and 12 h and 45 min on Anak Krakatau (Yamane, 2005). Abe mainly studied termite ecology, but also sampled ants during 16 days of his stay on the islands (Yukawa, 1989). Abe et al. (2012) reported the results of the expeditions. During I sampled ants as an experienced myrmecologist with the help of Dr. Syaukani of Syiah Kuala University (Indonesia) and Dr. Rosichon Ubaidillah of the Bogor Zoological Museum (Indonesia), and concentrated on colony collection to know the nesting habits because this information would be important in tracing the ways in which ants reached the islands. Manual collection of foragers was also adopted to collect as many species of ant as possible. Attention was paid to lower vegetation (see Wara et al., 2008 for the results with netsweeping), leaf litter, dead or decayed twigs/branches/wood, and dead portions of living trees. Ants in the soil (up to 10 cm deep) were sampled with a sifter and pan. Powdered cheese baits were used to attract surface foragers. Ants attracted to extrafloral nectaries (EFNs) and homopteran insects were kept in bottles separately. The list of ants given below was compiled mainly based on the data presented by Dammerman (1948), Abe et al. (2012) (see also Yamane 2005), Wara et al. (2008) and Yamane (2008, unpublished report submited to the Japan Society for Promotion of Science). I did not have the chance to examine the specimens used by Dammerman (1948). This has posed difficulty in matching species names between his material collected up to 1933 and our material collected after 1980, except when his specimens were used in modern revisions (e.g. Ward 2001 for Tetraponera). However, I carefully examined synonymic lists, descriptions and morphological comments that appeared in the literature treating the materials collected by E. R. Jacobson and K. W. Dammerman (e.g. Forel 1909; Wheeler 1924, 1937; Dammerman 1948). The specimens collected in 1982 were stored separately by Abe and Yamane. Part of the material collected by Abe had been kept by Dr. Keiichi Onoyama in good condition until it was sent to Yamane in After the death of Abe in 2000 his wet specimens had not been given sufficient care until they moved to the Kitakyushu Museum of Natural History and Human History. Most of the vials containing ants had lost ethanol, but they were point-mounted in 2011 by Yamane. I think most of the specimens collected by Abe are now available for examination (see Abe et al., 2012). All the specimens collected by Yamane were point-mounted. A set of species (probably not complete) was returned to Bogor Zoological Museum (Indonesia) within five years. Another set was sent to Abe to produce a joint paper, which, however, was never published owing to his unexpected death (but see Yamane, 2005). This set was very probably sent to Dr. Robert Taylor, Australia (see below). Some dry specimens were left at Kagoshima University but the collection is hardly complete. Seventy-seven species are given in a tentative list of ants collected in 1982 that was prepared by Abe (hereafter simply Tentative List ; see Yamane, 2005). Having examined all the specimens located in Japan 73 species were recognised until Some important specimens on the Tentative List such as Leptogenys sp. and Cerapachys sp. collected by me were apparently missing. Fortunately, very recently (2011) another set of specimens that had been sent by Abe to the Australian National Insect Collection (ANIC) was located, and was temporarily moved to Kagoshima University through courtesy of Dr. Steven Shattuck, the Hymenoptera curator of the collection, and Dr. Shingo Hosoishi of Kyushu University. All the specimens in this set were point-mounted specimens collected by me. Taking all these into account, the species number amounted to 79. Some of the point-mounted specimens prepared by Yamane might not have been located yet, since specimens corresponding to the records for particular islands mentioned in the Tentative List are missing. A list was finally compiled by Abe et al. (2012). Most of the specimens collected in were pointmounted and identified by me. In the list given below, the scientific name, synonymic list, brief description, distribution range, biological note, and collection records are given for each species following the style adopted by Dammerman (1948). This seems to give an impression of very classical style, which, however, is useful for researchers who want to conduct their own analyses. Keys to species are presented for most of the genera containing more than two Krakatau species. The actual numbers of genera and species are given for each survey period: 1908 (1 st survey), (2 nd ), (3 rd ), (4 th ), and (5 th ). The presence/absence records for each island are summarized in Table 1. The photographs of the Krakatau Islands, their vegetation and ants in life were taken by me. All the photographs of ant specimens were taken by Dr. Weeyawat Jaitrong of the Thailand Natural History Museum. Multi-focused montage images were produced using Helicon Focus 4.75 Pro from a series of source

3 A review of the ant fauna of the Krakatau Islands, Indonesia 3 Table 1. List of ants known from the Krakataus through the five survey periods Subfam. Species RK SR PN RK SR PN RK SR PN AK RK SR PN AK RK SR PN AK 1 Dol. Chronoxenus wroughtonii 2 Dolichoderus thoracicus 3 Iridomyrmex anceps 5 Ochetellus sp. 1 of SKY 6 Philidris cordatus 7 Philidris myrmecodiae 4 Tapinoma krakatauae 8 Tapinoma melanocephalum* 9 Tapinoma sp. 7 of SKY 10 Tapinoma sp. 16 of SKY 11 Technomyrmex albipes* 12 Technomyrmex difficilis* 13 Technomyrmex horni 14 For. Acropyga acutiventris 15 Acropyga sp. 15 of SKY 16 Anoplolepis gracilipes* 17 Nylanderia bourbonica* 18 Nylanderia taylori 19 Nylanderia sp. 5 of SKY 20 Paraparatrechina emarginata 21 Paraparatrechina cf. opaca 22 Paraparatrechina sp. 8 of SKY 23 Paratrechina longicornis* 24 Pseudolasius familiaris 25 Pseudolasius minutus 26 Oecophylla smaragdina 27 Camponotus leonardi 28 Camponotus sp. 9 of SKY 29 Camponotus sp. 38 of SKY 30 Camponotus sp. 128 of SKY 31 Camponotus bedoti 32 Camponotus cf. 101 of SKY 33 Camponotus arrogans 34 Camponotus cleon 35 Camponotus festinus 36 Camponotus sp. 48 of SKY 37 Camponotus sp. 72 of SKY 38 Camponotus sp. 153 of SKY 39 Camponotus sp. 154 of SKY 40 Echinpla lineata 41 Polyrhachis arcuata 42 Polyrhachis sp. cf. lepida 43 Polyrhachis illaudata 44 Polyrhachis proxima 45 Polyrhachis ristemai 46 Polyrhachis cf. subpilosa 47 Polyrhachis vindex 48 Polyrhachis abdominalis 49 Polyrhachis armata 50 Polyrhachis bicolor 51 Polyrhachis caligata 52 Polyrhachis dives 53 Polyrhachis flavoflagellata 54 Pseud. Tetraponera allaborans 55 Tetraponera attenuata 56 Tetraponera nitida 57 Tetraponera rufonigra 58 Cer. Cerapachys sp. 64 of SKY 59 Amb. Prionopelta kraepelini 60 Pon. Anochetus graeffei 61 Cryptopone sp. 11 of SKY 62 Hypoponera confinis 63 Hypoponera sp. A (=RK-1) 64 Hypoponera sp. B (=RK-2) 65 Hypoponera sp. C (=RK-3) 66 Hypoponera sp. D (=RK-4) 67 Hypoponera sp. E (=RK-6)

4 4 Table 1. (continued) Subfam. Species RK SR PN RK SR PN RK SR PN AK RK SR PN AK RK SR PN AK 68 Hypoponera sp. F (=RK-8) 69 Leptogenys sp. cf. peuqueti 70 Myopias breviloba 71 Myopias sp. 11 of SKY 72 Odontomachus simillimus 73 Odontoponera denticulate 74 Pachycondyla sp. cf. 28 of SKY 75 Ponera sp. A (=RK-2) 76 Ponera sp. B (=RK-3) 77 Platythyrea paralella 78 Myr. Pyramica doherti 79 Pyramica karawajewi 80 Strumigenys emmae* 81 Strumigenys godeffroyi 82 Lordomyrma sp. 3 of SKY 83 Vollenhovia sp. 70 of SKY 84 Monomorium destructor* 85 Monomorium floricola* 86 Monomorium cf. monomorium 87 Monomorium pharaonis 88 Monomorium sp. cf. sechellense 89 Monomorium sp. 1 of SKY 90 Oligomyrmex sp. 33 of SKY 91 Solenopsis sp. 1 of SKY 92 Solenopsis sp. 15 of SKY 93 Rhoptromyrmex rawlinsoni 94 Rhoptromyrmex wroughtonii 95 Tetramorium bicarinatum* 96 Tetramorium sp. cf. insolens 97 Tetramorium lanuginosum* 98 Tetramorium pacificum* 99 Tetramorium simillimum* 100 Tetramorium tonganum 101 Pheidole cf. dammermani 102 Pheidole fervens* 103 Pheidole hortensis 104 Pheidole megacephala* 105 Pheidole miseranda 106 Pheidole sp. cf. oceanica 107 Pheidole plagiaria 108 Pheidole sauberi 109 Pheidole nodgii verlatensis 110 Pheidole sp. A (=RK-18) 111 Pheidole sp. B (=RK-19) 112 Crematogaster ferrari 113 Crematogaster jacobsoni 114 Crematogaster dohrni artifex 115 Crematogaster rogenhoferi 116 Crematogaster sp. 39 of SKY 117 Crematogaster cf. treubi 118 Crematogaster sewardi 119 Crematogaster baduvi 120 Liomyrmex gestroi 121 Cardiocondyla sp. cf. kagutsuchi* 122 Cardiocondyla tjibodana 123 Cardiocondyla wroughtonii 124 Cardiocondyla sp. 5 of SKY 125 Myrmecina sp. RK Pristomyrmex brevispinosus Actual and cumulative sp. numbers** (39) 39 (54) 81 (98) 99 (125) RK, Rakata; SR, Sertung; PN, Panjang; AK, Anak Krakatau. Species marked with * are tramps. **: Figures in parentheses are cumulative numbers.

5 A review of the ant fauna of the Krakatau Islands, Indonesia 5 images taken by a Nikon EOS Kiss 4 digital camera attached to a Nikon ECLIPSE E600 microscope. Voucher specimens for 1982 and will be mainly deposited in the Entomological Collection at Bogor Zoological Museum (Cibinong, Indonesia), the SKY Collection at the Kitakyushu Museum of Natural History and Human History (Kitakyushu, Japan), and the Australian National Insect Collection (ANIC) (Canberra, Australia). Krakatau Islands The volcanic history and the present configuration of the Krakatau Islands are repeatedly presented in the literature (e.g., Dammerman, 1948; Simkin and Fiske, 1983; Thornton, 1996; Winchester, 2003). The Krakataus consist of four small islands, i.e., Rakata (11.52 km 2 around 1980), Sertung (7.84), Panjang (2.72) and Anak Krakatau (2.80) (Fig. 1). Rakata is the remnant of the former larger island Krakatau (33 km 2 ), of which two-thirds sank beneath the sea at the time of the destructive explosion in 1883 (Dammerman, 1948). Anak Krakatau is a young volcano; it arose above the sea in 1927 and established itself by The areas of islands are still changing, mainly by continuous eruptions of Anak Krakatau (Thornton, 1996, pp ) and moving of sand around Sertung. Krakatau is located km from both the western coast of Java and the southern coast of Sumatra. Two islands, Sebesi and Sebuku, lie between Krakatau and Sumatra. Sebesi is located km from either of Sertung and Sumatra. The vegetation change from 1883 to the early 1980s has been reviewed by Docters van Leeuwen (1936), Tagawa et al. (1985), Whittacker, Bush, and Richards (1989), and Thornton (1996). ENUMERATION OF SPECIES The arrangement of the subfamilies, tribes and genera follows Bolton (2003). The species are arranged alphabetically Fig. 1. Location of the Krakatau Islands. (Modified from Tukirin et al., 1993). within each genus. Among the 126 species listed below Tapinoma krakatauae (only collected in the second survey; no. 4 in the list) is probably conspecific with Tapinoma sp. 7 of SKY (found in the last survey; no. 8). Therefore, it is counted among the actual species number for the second survey period, but is omitted from the cumulative species number for the last survey period. The names of the four islands are abbreviated as follows: RK for Pulau Rakata (=P. Krakatau, P. Rakata Besar), SR for P. Sertung (=P. Verlaten), PN for P. Panjang (=P. Rakata Kecil, P. Lang), and AK for P. Anak Krakatau. The names of the collectors are abbreviated as follows: DVL (W.M. Docters van Leeuwen), ERJ (E.R. Jacobson), KWD (K.W. Dammerman), RU (Rosichon Ubaidillah), SKY (Sk. Yamane), and TA (T. Abe). Collection data (month/year, island and collector) are italicized when the identity of the material is not completely sure. Subfamily DOLICHODERINAE 1. Chronoxenus wroughtonii javanus (Forel, 1909) (Pl. 7, A & B) Bothriomyrmex wroughtonii var. javanus: Wheeler 1924: 252; Dammerman 1948: 374. Bothriomyrmex wroughtonii javanus: Tentative List (cf. Yamane 2005: 30); Abe et al. 2012: 67. Chronoxenus wroughtonii javanus: Heterick & Shattuck 2011: 166. Small species with a quadrate head; the head and mesosoma are light brown and the gaster much darker. This form was described from Java based on a single queen (Forel, 1909). No formal description is available of the worker caste, while Dammerman (1948) gave a brief diagnosis. Although I have not yet compared my specimens with those from Java (the type locality), the workers collected in 1982 and 2005 are tentatively considered to be of this form. No queen material is available from the Krakataus. A colony was found from a dead twig on the ground on Anak Krakatau in May 1908, RK & PN (ERJ); Apr. 1920, RK (KWD); Jan RK (KWD); Nov. 1982, AK (TA); Aug. 2005, AK (SKY). 2. Dolichoderus thoracicus (F. Smith, 1860)-complex (Pl. 7, C & D) Dolichoderus (Hypoclinea) sp.: Tentative List (cf. Yamane 2005: 30). Dolichoderus thoracicus-complex: Abe et al. 2012: 67. This is the only species of the genus Dolichoderus recorded from the Krakataus. A relatively small blackish species with the head and mesosoma densely sculptured; the mesosoma often has a reddish tinge. This species is easily distinguished from the other Krakatau

6 6 dolichoderines by the hard body, deeply concave posterior face of propodeum, and apically truncate petiolar node. Workers and a foundress queen were collected. This species was also collected on Sebesi and Sebuk (Wara et al. 2008), and ranges widely in tropical Asia. Jul. 1982, RK & PN (SKY); Nov. 1982, AK (TA); Aug. 2005, RK & PN (SKY); Jan. 2007, SR (SKY). 3. Iridomyrmex anceps (Roger, 1863) (Pl. 7, E & F) Iridomyrmex sp. 1: Tentative List (cf. Yamane 2005: 30). Iridomyrmex anceps: Wara et al. 2008: 4, Abe et al. 2012: 67. A long-legged dolichoderine with the head not concave posteriorly in full-face view, and the propodeum not concave posteriorly. This species has not been found on P. Rakata, which has the most developed vegetation among the four islands. In this species was found in a sparse Casuarina forest on Anak Krakatau. Workers were seen foraging on lower vegetation as well as on the ground, and were collected by sweeping (Wara et al., 2008). Jul. 1982, SR & AK (SKY); Nov. 1982, PN & AK (TA); Aug. 2005, AK (RU, SKY); Dec. 2006, AK (SKY). 4. Ochetellus sp. 1 of SKY (Pl. 7, G & H) Ochetellus sp. 1: Wara et al. 2008: 4. Small black ant with a posteriorly concave propodeum. Foragers were found on the beach, and also from lower vegetation on Anak Krakatau. Aug. 2005/Dec. 2006, AK (SKY); Aug. 2005, AK (RU). 5. Philidris cordatus protensus (Forel, 1911) Iridomyrmex cordatus protensus var. butteli Forel: Wheeler 1937: 23, Dammerman 1948: Jan. 1933, SR; Apr. 1934, RK (KWD). 6. Philidris myrmecodiae (Emery, 1887) (Pl. 7, I & J) Iridomyrmex myrmecodiae: Docters van Leeuwen 1936: (biology). Iridomyrmex cordatus fuscus var. jactans Forel: Wheeler 1937: 23, Dammerman 1948: Iridomyrmex sp. 2: Tentative List (cf. Yamane 2005: 30).?Philidris sp. 1: Wara et al. 2008: 4. Philidris myrmecodiae: Abe et al. 2012: 67. At present I do not know any reliable characters distinguishing between isolated workers of P. cordaus and P. myrmecodiae. All the Philidris workers collected in 1982 and seem to belong to one species, probably P. myrmecodiae. They are smaller and less variable in size than the supposed P. cordatus from the Malay Peninsula and Borneo. Males collected from Colony RK06-SKY-34 on Sertung are distinctly smaller than males of the supposed P. cordatus from Malay Peninsula. It is even possible that the two forms recorded by Dammerman (1948) are actually of the same species. In nests were found in dead twigs on vegetation (2 colonies), rotting twigs on the ground (2), an abandoned termite nest (1), and rotting wood (1). Foragers were attracted to extrafloral nectaries of Hibiscus tiliaceus L. on Rakata and Macaranga tanarius (L.) Müll. Arg. on Anak Krakatau; in the latter case shelters were constructed by foragers on the leaf. Docters van Leeuwen (1936) found colonies of Iridomyrmex myrmecodiae living in the hollow rhizomes of an epiphytic fern, Polypodium sinuosum [Myrmecophila sinuosa (Hook.) T. Nakai ex H. Ito], at an elevation of 300 m on Rakata. 1931, RK (DVL); Apr. 1933, RK (KWD); Jul./Aug. 1982, RK, SR & PN (SKY); Oct./Nov. 1982, RK, SR & AK (TA); Aug. 2005, RK, SR, PN & AK (SKY); Dec. 2006, SR (SKY); Jan. 2007, RK, SR & PN (SKY). 7. Tapinoma krakatauae (Wheeler, 1924) Iridomyrmex krakatauae Wheeler 1924: 252, Dammerman 1948: 373, Bolton 1995: 218. Tapinoma krakatauae: Heterick & Shattuck 2011: 166. This is a very small Iridomyrmex described from Rakata based on an incomplete worker specimen (petiole and gaster missing). No additional specimen has been found since the original description. Shattuck (1992) provisionally included this species in Iridomyrmex but had some doubt about its placement because of the lack of sufficient information. According to Dr. Stefan Cover the type material of this species is not deposited in the Museum of Comparative Zoology at Harvard. Heterick & Shattuck (2011) transferred this species to Tapinoma. See under Tapinoma sp. 7 of SKY below. Sept. 1920, RK (KWD). 8. Tapinoma melanocephalum (Fabricius, 1793) Tapinoma melanocephalum F.: Wheeler 1937: 23, Dammerman 1948: 374; Tentative List (cf. Yamane 2005: 30); Abe et al. 2012: 67. Much smaller than the following species, with the total body length slightly more than 1 mm and head width less than 0.4 mm. Antennal scape relatively longer, surpassing the posterolateral corner of head by 1/3 of its length. Head, pronotum, propodeum and part of gaster brown to blackish brown; mandible, antenna, mesonotum, anterior or median portion of gaster, and legs pale yellow. Dorsum of body sometimes darker over the surface, but mandible, antenna and legs always much paler. Dammerman (1948) mentioned that the body length was up to 3 mm, but even in the queen the body measures only slightly longer than 2 mm. This species was mainly found along the beach, but also seen inland. Workers foraged on the beach, lower vegetation, tree trunk etc. A colony including a queen and workers was

7 A review of the ant fauna of the Krakatau Islands, Indonesia 7 collected in 2005 from a dead twig of Hibiscus. Jan. 1933, SR (KWD); Oct./Nov. 1982, RK, PN & AK (TA); Aug. 2005, RK & AK (SKY); Dec. 2006, SR & PN (SKY); Jan. 2007, RK (SKY). 9. Tapinoma sp. 7 of SKY (Pl. 7, K & L) A relatively large species with the total body length ca. 2 mm and head width mm. The antenna slightly surpasses the posterolateral corner of the head. Mandible is short and broadened toward the base, with the apical half shining and basal half distinctly punctate. Whole body is finely and densely sculptured, covered with dense pubescence; long hairs are seen only along the anterior margin of clypeus. Body is uniformly dark brown to blackish, with basal 3/5 of the antennal scape and tarsi of all legs yellowish to whitish. This form well agrees in colour pattern, sculpture and pilosity with the original description of Iridomyrmex krakatauae; it differs from the latter only in the shape of mandible and relative length of the antennal scape. Anyway this form, among the Sundaland dolichoderines, is the only one with the antennal scape yellowish in its basal 3/5, which is one of the key characteristics defining I. krakatauae. In this species was found on all the four islands. Workers were mainly seen inland, but also found near the beach, and were collected from leaf litter and dead part of trees (but colony was not located). Aug. 2005, RK & SR (SKY), Jan. 2007, RK & PN (SKY). 10. Tapinoma cf. sp. 16 of SKY Very small species with the total body length around 1 mm. Body is light brown to brown; apical segments of the antenna, part of the head, and the gaster are slightly darker. Antennal scape is short, hardly surpassing the posterolateral corner of the head. Posterior face of the propodeum is rather distinctly margined laterally and dorsally. A worker was collected on the coast of P. Rakata, and a few workers from P. Sertung. This species was also found in a disturbed area of Carita, West Java in December, Dec. 2006, RK & SR (SKY). Genus Technomyrmex Dammerman (1948) recorded two species of Technomyrmex, both of which might have been misidentified (see below). In the Tentative List (see Yamane, 2005) three species collected in 1982 are listed. All these were also collected during the most recent surveys. Key to species of Technoimyrmex from the Krakataus 1. Body extensively light brown to brown. Anterior margin of clypeus with a semicircular median emargination. Dorsum of frontal carina without standing hairs... T. horni - Body entirely dark brown to black except for mandible (reddish), antennal flagellum (often yellowish), and tarsi of all legs (yellowish to whitish). Anterior margin of clypeus almost straight or very shallowly emarginate. Dorsum of frontal carina with standing hairs Dorsum of head behind level of posterior margin of eye lacking standing hairs... T. albipes - Dorsum of head behind level of posterior margin of eye bearing a pair of standing hairs... T. difficilis 11. Technomyrmex albipes (F. Smith, 1861) (Pl. 7, M & N) Technomyrmex albipes:?wheeler 1924: 252,?Dammerman 1929: 100,?Wheeler 1937: 23,?Dammerman 1948: 374, Tentative List (part) (cf. Yamane 2005: 30), Wara et al. 2008: 4, Abe et al. 2012: 67. Small black ant, measuring ca. 2 mm long. Body has a few standing hairs on the dorsum. Head behind the posterior margin of the eyes lacks standing hairs. Anterior margin of the clypeus is only very weakly emarginated. Propodeum in profile is not swollen dorsally. This is a famous tramp species widely distributed in Southeast Asia (Bolton, 2007). The older records of this species from the Krakataus may contain T. difficilis, which is very similar to this species in coloration and size. Foragers were found in forests on Sertung, and at the summit of Rakata in Wara et al. (2008) recorded this species collected by the net-sweeping of lower vegetation. Apr. 1920, RK (KWD); Nov. 1932, RK & AK (KWD); Apr. 1933, RK (KWD); Aug. 1982, SR (SKY); Oct./Nov. 1982, RK & SR (TA); Aug. 2005, RK & SR (SKY & RU); Dec. 2006, SR (SKY). 12. Technomyrmex difficilis Forel, 1892 (Pl. 8, A & B) Technomyrmex difficilis: Bolton 2007: 47, Abe et al. 2012: 67. This species is very similar to T. albipes, but is separated from the latter in having a pair of standing hairs on the dorsum of the head behind the level of the posterior margin of the eyes (in T. albipes standing hairs are missing in this area) (Bolton, 2007). Unfortunately the two species may not have been separated in Dammerman s papers. This is also a famous tramp species known from tropical Asia, New Guinea, Australia, Micronesia, Madagascar, USA, Puerto Rico, etc. It was only collected from P. Rakata and P. Panjang among the Krakataus. Oct. 1982, RK & PN (TA); Oct. 2000, PN (K. Ogata); Dec. 2006, PN (SKY). 13. Technomyrmex horni Forel, 1912 (Pl. 8, C & D) Tapinoma sundaicum Emery: Wheeler 1937: 23, Dammerman 1948: 374. Technomyrmex horni Forel: Bolton 2007: 84 (P. Rakata), Wara et al. 2008: 4, Abe et al. 2012: 67. Technomyrmex sp. 1: Tentative List (cf. Yamane 2005: 30). Head, antennae, mesosoma, petiole and legs are light

8 8 brown to brown, with the head slightly darker and mid- and hind coxae whitish; gaster dark brown. Dorsum of the head, mesosoma and gastral tergite 1 lacks standing hairs. Clypeus has a deep and broad emargination at the apex. According to Dammerman s brief description, his Tapinoma sundaicum (identified by W. M. Wheeler) should be Technomyrmex horni, although I did not examine the specimens. In 1982 workers were collected at altitudes of m on Rakata. In 2005 and 2006 foragers were found in the forest on Rakata (Plot 3 to summit), at extrafloral nectaries of Hibiscus trees near the coast of Anak Krakatau, and from the lower vegetation in the forest of Sertung. Dr. Rosichon collected workers on Sertung and Panjang by net-sweeping of the lower vegetation (Wara et al. 2008). This species was also found in a forest at Carita, West Java in December, Apr. & Dec. 1933, SR (KWD); Jul. 1982, RK (SKY); Nov. 1982, AK (TA); Aug. 2005, RK (SKY); Aug. 2005, SR & PN (RU); Dec. 2006, SR & AK (SKY). Subfamily FORMICINAE Tribe Lasiini Genus Acropyga In addition to Acropyga acutiventris, two unidentified species supposedly of Acropyga were collected by T. Abe in He identified them as Atopodon sp. (from Rakata, Sertung and Panjang) and Rhizomyrma sp. (Rakata) (see Yamane, 2005). I located the specimens probably of his Atopodon sp. and found them to be a species closely related to Acropyga nipponensis. The specimens of Rhizomyrma sp. could not be located this time. Both Atopodon and Rhizomyrma are junior synonyms of Acropyga (see, LaPolla, 2004). Rhizomyrma sp. is not included in the actual species number for 1982 or in the total number of species recorded from the Krakataus. 14. Acropyga acutiventris Roger, 1862 (Pl. 8, E & F) Acropyga sp.: Tentative List (cf. Yamane 2005: 30). Acropyga acutiventris: Abe et al. 2012: 67. This is one of the most common Acropyga species in tropical Asia (LaPolla, 2004). Workers measure mm in total length. Mandible bears 5 teeth; the third tooth is very small, often vestigial. In 1982 Yamane and Abe collected many workers of this species from soil on Rakata. In 2005 Yamane found a colony (RK05-SKY-191) nesting in rotting wood and partly in soil on Rakata (in Plot 3), and another (RK05-SKY-192) from soil at around 400 m alt. (in Plot 2). Jul. 1982, RK (SKY); Oct. 1982, RK (TA); Aug. 2005, RK (SKY & Syaukani). 15. Acropyga sp. 15 of SKY Atopodon sp.: Tentative List (cf. Yamane 2005: 30). Acropyga sp. 15 of SKY: Abe et al. 2012: 67. This is very similar to A. nipponensis Terayama in the structure of the mandible, but is much smaller than the latter. In body size it is similar to A. inezae Forel, measuring slightly more than 1 mm. A colony (RK07-SKY-25) was found from shallow soil on Panjang in June A winged female and several workers were collected from it. Oct. 1982, RK (TA); Jan. 2007, PN (SKY). 16. Anoplolepis gracilipes (F. Smith, 1857) (Pl. 8, G & H) Plagiolepis longipes Jerdon: Forel 1909: 229, Jacobson 1909: 199, Dammerman 1948: 376. Plagiolepis (Anoplolepis) longipes: Wheeler 1924: 253. Anoplolepis longipes: Wheeler 1937: 23, Tentative List (cf. Yamane 2005: 30). Anoplolepis gracilipes: Wara et al. 2008: 4, Abe et al. 2012: 67. This famous tramp species has been very common on all the islands of Krakatau, and also in West Java and southern Sumatra, and on P. Sebesi, P. Sebuku and P. Legundi located between the Krakataus and Sumatra. Jacobson (1909) reported that this species was widespread on the Krakatau Islands in According to Dammerman (1948) it occurred also on Sebesi in great numbers. In 2005 to 2007 I found this species on all the Krakatau Islands, but it was never found together with Oecophylla smaragdina at the same points and on the same trees. Oecophylla smaragdina was mainly confined to coastal areas, but A. gracilipes was also found deep in the forest. In August 2005 the density of A. gracilipes was extremely high in a dark forest near the coast on Rakata. It used almost every substratum at the ground level for nesting, i.e., under stones, under logs, among leaf litter, in rotting wood, etc. However, during December 2006 and January 2007 I could not find any individual of this species at the abovementioned site. Wara et al. (2008) reported that this species was frequently collected on all the islands by net-sweeping of lower vegetation in August On Sebesi, one very wet forested place was completely occupied by this species in August I observed workers attending extrafloral nectaries of Hibiscus tiliaceus near the coast of Anak Krakatau. A winged female was collected from a nest under a log (RK06-SKY-031) on Sertung on 30 Dec Foundress and winged queens were collected from a colony (RK05-SKY-067) in a dead stump in a forest on Sebuku on 14 August May 1908, RK & PN (ERJ); Dec. 1919, SR (KWD); Apr. 1920, RK (KWD); 1921, PN (KWD); Nov. 1932, RK & SR (KWD); Jan. & Nov. 1933, SR (KWD); 1933, PN (KWD); Jul. 1982, RK & SR (SKY); Oct./Nov. 1982, RK, SR, PN & AK (TA); Oct. 2000, Krakatau Islands (Ogata et al.); Aug. 2005, RK, SR & AK (SKY, RU & Syaukani); Dec. 2006, RK, SR & AK (SKY).

9 A review of the ant fauna of the Krakatau Islands, Indonesia 9 Tribe Plagiolepidini Four genera, Nylanderia, Paraparatrechina, Paratrechina, and Pseudolasius, have been recorded from the Krakataus. The former three were teated by Dammerman (1948) as belonging to Prenolepis. Genera Nylanderia, Paraparatrechina and Paratrechina Wheeler (1924) and Dammerman (1948) recorded four species of Nylanderia from the Krakataus, but one species was represented by only one male specimen, which might be the male of one of the other three species, and is omitted from the present list. Prenolepis (Nylanderia) emarginata Forel was transferred to Paraparatrechina by LaPolla et al. (2010). Accordingly I recognize two Nylanderia species and one Paraparatrechina species in Dammerman s synthesis. Abe and Yamane collected five species of Paratrechina in 1982: two species of Nylanderia, two species of Paraparatrechina, and one species of Paratrechina. Yamane collected the same five species in Key to species of Nylanderia, Paraparatrechina and Paratrechina from the Krakataus (workers). 1. Propodeum with a pair of erect setae [Scape, femora and tibiae without distinct erect hairs. Erect hairs on mesosomal dorsum distinctly paired. Mandible with 5 teeth.]: Genus Paraparatrechina Propodeum without a pair of erect setae Head and mesosoma pale yellowish brown; gaster darker; all parts of body lacking bluish luster Paraparatrechina sp. 8 of SKY - Head and mesosoma reddish brown; gaster darker; propodeum and/or petiole often with bluish luster Total length 2 mm. Propodeal declivity with a bluish spot in certain lights... Paraparatrechina emarginata - Total length less than 1.5 mm. Dorsum of petiole with a bluish spot in certain lights... Paraparatrechina sp. cf. opaca 4. Mandible with 5 teeth. Erect hairs on head and sometimes on mesosoma not distinctly paired. Erect hairs absent on scape, but present on legs... Paratrechina longicornis - Mandible with 6 teeth. Erect hairs on head and dorsum of mesosoma more or less distinctly paired. Scape and legs with numerous erect hairs: Genus Nylanderia Head in full-face view oval, with posterior margin convex Nylanderia taylori - Head in full-face view more or less quadrate, with almost straight posterior margin Body 2 mm or more in total length. Eye larger, with ca. 15 ommatidia across long axis. Dorsum of promesonotum with several pairs of short erect hairs in addition to 4 pairs of long erect hairs. Dorsum of mesosoma covered with appressed pilosity... Nylanderia bourbonica - Body less than 2 mm long. Eye smaller, with at most ca. 10 ommatidia across long axis. Dorsum of promesonotum generally bearing only 4 pairs of long setae. Dorsum of mesosoma virtually without appressed pilosity Nylanderia sp. 5 of SKY 17. Nylanderia bourbonica (Forel, 1884) (Pl. 8, I & J) Nylanderia bourbonica bengalensis: Wheeler 1937: 24. Prenolepis bourbonica bengalensis: Dammerman 1948: 375. Paratrechina bourbonica: Tentative List (see Yamane 2005: 30) Nylanderia bourbonica: Abe et al. 2012: 67. Tentatively I assign one of the most common Nylanderia from the Krakataus to Dammerman s Prenolepis bourbonica bengalensis. As I have not examined the type material of either bourbonica or bengalensis, my adoption of the name N. bourbonica is just tentative. So-called N. bourbonica may comprise several sibling species. Workers from the Krakataus have the following characteristics: Body around 2.5 mm in total length. Head slightly longer than broad; eye large, with ca. 15 ommatidia along long axis; its maximum length only slightly smaller than the length of apical segment of antenna; clypeus with a blunt median carina. Head and gaster superficially sculptured and somewhat dull; mesosoma more weakly sculptured with the sides almost smooth. Whole body covered with relatively thick short appressed pilosity as well as many strong erect hairs; promesonotum dorsally with 4 pairs of long and thick erect hairs and 4 5 pairs of shorter ones. Body dark or blackish brown, with the gaster slightly darker; fore trochanter and tarsi of all legs yellowish. Nylanderia bourbonica is a famous tramp species, very common throughout Southeast Asia, especially in disturbed areas. On the Krakatau Islands except for Panjang, it was common during 2005 to It was also collected in West Java (Carita), and on Sebesi Island. On the Krakataus this species was found from the beach through Casuarina forests to the forest interior. A nest was located in a landed log on the beach (RK06-SKY-004) on Sertung, and another in a dead twig of a big tree (RK07-SKY- 014) on Panjang. Workers were collected from the lower vegetation and leaf litter as well as ground surface. Jan./Apr./Dec. 1933, SR (KWD); Apr. 1933, RK (KWD); Jul. 1982, SR & AK (SKY); Oct./Nov. 1982, RK, PN & AK (TA); Aug. 2005, RK, SR & AK (SKY); Dec. 2006, RK, SR & AK (SKY); Jan. 2007, RK (SKY). 18. Nylanderia taylori Forel Nylanderia taylori: Wheeler 1937: 24. Prenolepis taylori: Wheeler 1924, 253; Dammerman 1948: 375. According to Bingham (1903) and Dammerman (1948) this species, originally described from India, has a characteristically oval-shaped head. The material in my collection does not have specimens with this condition. Dec. 1919, RK (KWD); Apr. 1920, RK (KWD); Oct. 1921, SR (KWD); May 1929, RK (DVL); May 1929, AK (KWD).

10 Nylanderia sp. 5 of SKY (Pl. 8, K & L) Paratrechina?taylori: Tentative List (cf. Yamane 2005: 30) Nylanderia sp. 5 of SKY: Abe et al. 2012: 67. A medium-sized species measuring slightly less than 2 mm long. Head is in frontal view nearly quadrate. Eye is relatively large, with ca. 10 ommatidia along the longitudinal axis; the length between the anterior margin of the eye and the posterior margin of the clypeus is shorter than the maximum eye length. Fifth mandibular tooth is slightly smaller than the fourth tooth (counted from apex). Body surface is extensively smooth and shiny. Dorsum of the promesonotum typically has 4 pairs of strong erect hairs and 0 2 pairs of much shorter hairs; appressed pilosity is sparse on the head, and almost absent on the mesosoma and gaster. Head and mesosoma are brown, but the mesosoma is often paler than the head; the gaster is much darker. Workers collected on Panjang measure only 1.5 mm in total length and have fewer ommatidia. This species was commonly found on all the Krakatau Islands, and also in West Java (Carita), P. Sebesi and P. Sebuku during 2005 to I found this species from the beach to forest interior, but more commonly in the forest. A colony (RK05-SKY-173) was found in a dried branch on the ground on Rakata. Foraging workers were attracted to powdered-cheese baits set up on logs on Sertung (RK05-SKY-092, 098). A winged queen and a male were also attracted (092). Foragers were also collected by sifting leaf litter and surface soil on Panjang. Jul. 1982, RK & SR (SKY); Oct. 1982, RK & AK (TA); Aug. 2005, RK, SR & PN (SKY); Dec. 2006/Jan. 2007, PN & AK (SKY). 20. Paraparatrechina emarginata (Forel, 1913) Prenolepis (Nylanderia) emarginata: Wheeler 1924: Prenolepis emarginata: Dammerman 1948: 375. Total body length is 2 mm (Dammerman 1948). According to Wheeler (1924), the workers have a peculiar metallic blue spot on the propodeal declivity visible only in certain lights. Apr. 1920, RK (KWD) 21. Paraparatrechina cf. opaca (Emery, 1887) (Pl. 8, M & N) Paratrechina sp. 3: Tentative List (cf. Yamane 2005: 30). Paraparatrechina cf. opaca: Abe et al. 2012: 68. This species is very similar to P. opaca (Emery) described from Java. It is also similar to P. emarginata, but is constantly much smaller (less than 1.5 mm long). Head and mesosoma are brown; the gaster is blackish brown. Propodeal declivity, the dorsum of the petiole and the hind coxa often have a metallic blue luster visible in certain lights. Jul. 1982, RK (SKY); Oct. 1982, RK (TA); Aug. 2005, RK & PN (SKY). 22. Paraparatrechina sp. 8 of SKY (Pl. 9, A & B) Paraparatrechina sp. 8 of SKY: Abe et al. 2012: 68. Paratrechina sp. 2: Tentative List (cf. Yamane 2005: 30). Small species measuring less than 1.5 mm in total length. Head is rather elongate, distinctly longer than broad. Mandible bears 6 teeth; the third and fifth teeth (counted from apex) are much smaller than the rest. Eye is moderate in size, with ca. 9 ommatidia along the long axis; the distance between the anterior margin of the eye and the posterior margin of the clypeus is slightly shorter than the maximum length of the eye. Antennal scape is short, passing the posterior margin of the head by its 1/4 length. Dorsa of the head and mesosoma are superficially sculptured and weakly shiny; the lateral face of the mesosoma are smooth and shiny. Dorsa of the head, mesosoma and gastral tergites have dense appressed pilosity; the lateral face of the mesosoma almost lacks pilosity. Head and mesosoma are yellow to pale yellowish brown; the gaster is darker; the antenna and legs are yellowish, but often partly darkened. This species was relatively common on Sertung, Panjang and Anak Krakatau, and also on Sebuku. Workers were collected from the lower vegetation in Casuarina forests on Anak Krakatau, and in forests on Sertung and Panjang. A colony (RK05-SKY-164) was found inside an abandoned nest of a termite, Nasutitermes matangensis, on Panjang, and another (RK05-SKY-089) in rotting wood on Sertung. The latter colony contained some males. Oct. 1982, AK (TA); Aug. 2005, SR, PN & AK (SKY). 23. Paratrechina longicornis (Latreille, 1802) Prenolepis (Paratrechina) longicornis: Wheeler 1924: 252. Prenolepis longicornis: Dammerman 1948: 375. Paratrechina longicornis: Tentative List (cf. Yamane 2005: 30), Wara et al. 2008: 4, Abe et al. 2012: 68. This is the only member of the genus Paratrechina (La- Polla et al., 2010), and is famous tramp species found all over tropical regions of the world. During 2005 to 2007 this species was collected only on Sertung and Anak Krakatau. It was also collected in West Java (Carita) and P. Sebesi. This species occurred near the coast and in forest gaps. Workers were collected from leaf litter (RK06-SKY-038), lower vegetation (by sweeping; Wara et al. 2008), and extrafloral nectaries on Anak Krakatau. A colony was located in a decayed log on the ground in a forest on Anak Krakatau. May 1908, RK (ERJ); Apr. 1920, RK (KWD); Oct. 1921, SR (KWD); Nov. 1982, PN & AK (TA); Aug. 2005, AK (SKY); Dec. 2006, SR & AK (SKY). Genus Pseudolasius Two species of Pseudolasius were collected during 1933 and 1934 by Dammerman (1948). In 1982 Abe collected a very minute species, which was also collected by me during

11 A review of the ant fauna of the Krakatau Islands, Indonesia Pseudolasius familiaris (F. Smith, 1860) Pseudolasius familiaris F. Smith: Wheeler 1937: 24, Dammerman 1948: 375. According to Dammerman (1948) the workers of this species are brownish yellow with a dark brown gaster, and measure 6 7 mm in majors and mm in minors. Our collection does not contain this species. April 1934, Rakata (KWD). 25. Pseudolasius minutus Emery, 1896 (Pl. 9, C & D) Pseudolasius minutus Emery: Wheeler 1937: 24, Dammerman 1948: 376, Abe et al. 2012: 68. According to Dammerman (1948) only the queen and male have been known from the Krakatau. This species has been recorded from Java and Sumatra solely based on the queen and male. We collected very minute workers of Pseudolasius in 1982 and during from Rakata. I tentatively assign these workers to this species. Tentative description of the minor worker: Body measuring less than 1.5 mm. Head longer than broad, with medially weakly emarginate posterior margin in full-face view. Eye very small, at most as large as third antennal segment, often vestigial. Mandible with 5 teeth that decrease in size gradually from apical to basal ones. Mesosoma short; in profile dorsal outline of mesonotum flat; propodeal declivity steep. Entire body smooth and shiny (head sculptured very superficially). Dorsum of head covered with short appressed pilosity and relatively short suberect hairs. Mesosoma and gaster with much sparser appressed pilosity, but long erect hairs abundant; ca. 10 erect hairs present on the dorsum of propodeum. April 1933, Rakata (KWD); Oct. 1982, RK (TA); Aug. 2005, RK (SKY); Jan. 2007, PN (SKY). Tribe Oecophyllini 26. Oecophylla smaragdina (Fabricius, 1775) (Pl. 9, E & F) Oecophylla smaragdina: Jacobson 1909: 200, Forel 1909: 229, Dammerman 1922: 98, Wheeler 1924: 253, Dammerman 1929: 100, Wheeler 1937: 24, Dammerman 1948: 376, Tentative List (cf. Yamane 2005: 30), Ogata et al. 2001: 57, Abe et al. 2012: 68. This species was first recorded in 1908 on Rakata and Panjang, and thereafter has been constantly found except on Anak Krakatau, where the first record was made in 1982 by the Japanese team. During , it was most common along the forest edge facing the coast and the sparse forest near the coast. On Anak Krakatau foragers were seen visiting Hibiscus extrafloral nectaries. May 1908, RK & PN (ERJ); Dec. 1919, SR (KWD); Sept. 1920, RK (KWD); 1921, RK & PN (KWD); 1933, RK, SR & PN (KWD); Jul. 1982, RK, SR, PN & AK (SKY); Nov./Dec. 1982, RK, PN & AK (TA); Aug. 2005, RK, SR, PN & AK (SKY); Dec. 2006, RK, SR, PN & AK (SKY). Tribe Camponotini Genus Camponotus This is a large genus distributed worldwide, with numerous species, most of which are difficult to identify. By the end of the 1930s 6 species had been recorded from the Krakataus. In 1982 Abe and Yamane collected 9 species (Abe et al., 2012; but only 5 in Tentative List). In I collected 8 species. It is very difficult to couple the species listed by Dammerman (1948) with those collected by us. The subgenera Colobopsis and Myrmamblys In these subgenera the worker caste is rather distinctly dimorphic, though in Mymamblys intermediate individuals are not rare. According to Emery (1925) in Colobopsis the antennal insertion is at or near the midlength of the frontal carina, and the truncation of the major s head contains only part of the clypeus and is clearly defined. On the other hand, in Myrmamblys the antennal insertion is located distinctly in front of the midlength of the frontal carina, and the entire clypeus takes part in the rather indistinct truncation. However, in both characters intermediate conditions occur. Key to species of Colobopsis and Myrmamblys from the Krakataus 1. In major workers, head with a very distinct anterior truncation that is defined posteriorly and laterally by strong ridges; the truncation concave. Minor worker unknown, but dorsal outline of mesosoma probably rather evenly arched before propodeal declivity... C. (Colobopsis) cf. sp. 128 of SKY - In major workers, head with a less distinct truncation, which is not defined dorsally and laterally by distinct ridges. In minor workers, dorsal outline of mesosoma often interrupted at metanotal groove Body entirely black (only clypeus, mandible, and legs often with a tint of reddish brown), with dense relatively long, appressed or suberect pubescence over the dorsum of body; pronotum with dense, curved standing hairs; standing hairs on gaster shorter and straight C. (Colobopsis) leonardi-complex - Coloration and pilosity different from above; body rarely entirely black, often marked with yellowish or reddish brown; pronotum without long curved standing hairs Head in both major and minor workers densely punctate and mat; petiole in profile rather thick, node-like, with a rounded apex. Major workers measuring mm in total length; anterior half of head, including the entire clypeus, weakly truncate. Minor workers measuring mm in total length; dorsal outline of mesosoma in profile only slightly impressed in front of metanotal groove; propodeum in profile weakly concave at the middle Head in both major and minor workers superficially sculptured and somewhat shiny; petiole in profile thinner, scale-like, with a more acute apex. Major workers measuring less than 5 mm in total length; anterior portion of head more

12 12 distinctly truncate; the truncation including anterior portion of clypeus. Minor workers measuring less than 4 mm in total length; dorsal outline of mesosoma in profile with a deep, V- or U-shaped metanotal groove Mesosoma entirely dark brown to black. In the minor, head longer than broad; anterior border of propodeum distinctly elevated... C. (Myrmamblys) bedoti - Mesosoma reddish brown. In the minor, head almost as long as broad; anterior border of propodeum normal C. (Myrmamblys) cf. sp. 101 of SKY 5. A larger species; major worker measuring mm in total length; minor worker mm. In the minor, propodeum in profile with longer dorsal outline that is as long as or longer than propodeal declivity; dorsal outline more or less flat... C. (Colobopsis) sp. 9 of SKY - A smaller species; major worker measuring ca. 3.5 mm in total length; minor worker ca. 2.5 mm. In the minor worker, propodeum in profile with shorter dorsal outline that is shorter than propodeal declivity; dorsal outline more roundly convex... C. (Colobopsis) sp. 38 of SKY 27. Camponotus (Colobopsis) leonardi Emery, 1889-complex (Pl. 9, G & H) Camponotus sp. 2: Tentative List (cf. Yamane 2005: 30). Camponotus (Colobopsis) leonardi Emery-complex: Abe et al. 2012: 68. Minor workers measure around 5 mm in total length, and the major workers 8.5 mm. Body is black, but the mandible, clypeus, antennal funiculus and legs often have a reddish tinge. Mesosoma and gaster have dense, relatively long, pale yellowish pubescence; the pronotum has yellowish brown curved standing hairs. The truncation of the major s head is distinct, but the clypeus is dorsally and laterally not margined by ridges. Several species closely related to C. leonardi are known in Southeast Asia. They are separable from each other mainly on the basis of pilosity on the dorsa of the mesosoma and gaster. Jul. 1982, RK (SKY); Oct. 1982, RK (TA) 28. Camponotus (Colobopsis) sp. 9 of SKY (Pl. 9, I L) Camponotus vitreus angustatus Mayr: Forel 1909: 229, Dammerman 1922: 98, Wheeler 1924: 253, Dammerman 1929: 100, Wheeler 1937: 24. Camponotus sp. 4 (=vitreus angustatus?): Tentative List (cf. Yamane 2005: 30). Camponotus (Colobopsis) sp. 9 of SKY: Abe et al. 2012: 68. This species is related to C. vitreus (F. Smith) that should be a complex comprising several sibling species. It is very similar to C. sp. 38 of SKY, but is constantly larger than the latter (for other characters, see the key). This is a common species occurring throughout the Sundaland region. Specimens were also collected from Pulau Peucang (SKY) and Pulau Panaitan (TA) off Ujung Kulong, westernmost part of Java in I collected a nest of this species from rotting wood in January 2007 on Panjang. The nest (RK07-SKY-019) was producing winged queens. May 1908, RK (ERJ); Sept. 1920, RK (KWD); May 1932, PN (KWD); Apr. 1933, RK (KWD); Dec. 1933, SR (KED); Nov. 1982, PN (TA); Aug. 2005, RK (SKY); Jan. 2007, PN (SKY). 29. Camponotus (Colobopsis) sp. 38 of SKY (Pl. 10, A & B) Camponotus (Colobopsis) sp. 38 of SKY: Abe et al. 2012: 68. This is a very common ant throughout Sundaland and also found from the Philippines. On the Krakataus this species was very common from the seashore to forest interior, but I did not locate any nests. Foragers were collected from the lower vegetation, and observed attending extrafloral nectaries on Hibiscus trees on Anak Krakatau. Jul. 1982, SR & PN (SKY); Nov. 1982, RK & PN (TA); Aug. 2005, RK, SR & AK (SKY & Syaukani); Dec. 2006/Jan. 2007, RK, SR. PN & AK (SKY). 30. Camponotus (Colobopsis) cf. sp. 128 of SKY (Pl. 10, C & D) This is a typical Colobopsis species as seen in the temperate Palaearctic region (e.g., C. nipponicus), the major having a distinct truncation of the head margined by dorsal and lateral ridges. The clypeus has a median furrow on the posterior short plane, and a median carina on the anterior vertical face. Only a single major worker was collected at the forest edge near the seashore on Rakata. Jan. 2007, RK (SKY). 31. Camponotus (Myrmamblys) bedoti Emery, 1893 (Pl. 10, E H) Camponotus reticulatus bedoti: Forel 1909: 229, Dammerman 1922: 98. Camponotus bedoti: Wheeler 1924: 253, Dammerman 1929: 100, Wheeler 1937: 98, Dammerman 1948: 377, Abe et al. 2012: 68. Camponotus sp. 1 (=bedoti?): Tentative List (cf. Yamane 2005: 30). This is one of the commonest Myrmamblys species in Southeast Asia. Very commonly found from coastal forests to forest interior on the Krakataus. Nests were collected from rotting wood, dead twigs on the ground, and a dead twig on a living tree. Males and winged queens were found in some nests in August and January. Foragers were observed being attracted to extrafloral nectaries of Hibiscus trees on Sertung. May 1908, RK (ERJ); Dec. 1919, RK (KWD); Aug. 1930, SR (KWD); May 1932, PN (DVL); Apr. 1934, RK (KWD); Jul. 1982, RK, SR, PN & AK (SKY); Oct./Nov. 1982, RK, PN & AK (TA); Aug. 2005, RK, SR, PN & AK (SKY & Syaukani); Dec. 2006/Jan. 2007, RK, SR, PN & AK (SKY).

13 A review of the ant fauna of the Krakatau Islands, Indonesia Camponotus (Myrmamblys) cf. sp. 101 of SKY (Pl. 10, I & J) Camponotus (Myrmamblys) cf. sp. 101 of SKY: Abe et al. 2012: 68. Similar to the preceding species, but the body is partly marked with reddish brown. In the minor worker, the head is relatively broad and the propodeum is not raised anteriorly just behind the mesonotum. Nov. 1982, RK (TA). Half the Krakatau Camponotus species belong to the subgenus Tanaemyrmex, which is characterized as follows: Worker rather distinctly dimorphic but with series of intermediates. Head of major workers generally much broader posteriorly than anteriorly. Clypeus usually with median carina, anteriorly slightly produced to form a short lobe. Antenna generally long, inserted anteriorly to the midlength of frontal carina. Mesosoma in profile with dorsal outline gently arched, continuous without interruption. Petiole generally scale-like, but sometimes thicker. Foretibia without erect hairs. Most species are palecoloured and nocturnal. Key to the Karakatau species of the subgenus Tanaemyrmex 1. Body uniformly dark brown... C. cleon - Body rather distinctly bicolorous; mesosoma yellowish brown, head and gaster dark brown. In one species, head and mesosoma lighter and gaster dark Larger species; minor worker measuring more than 8 mm in total length; major worker measuring up to 15 mm. Mesosomal dorsum completely lacking standing hairs C. festinus - Smaller species; minor worker at most 7 mm in total length; major worker less than 10 mm. Mesosomal dorsum with many standing hairs With head in full-face view, gena without standing hairs, or at most with a few standing hairs posteriorly With head in full face view, gena with many standing hairs between eye and mandibular base Minor worker often with sparse standing hairs on gena posteriorly. Major worker with head microsculptured but rather shining; with head in full-face view antennal scape reaching or extending beyond posterolateral corner of head... C. sp. 153 of SKY - In minor worker gena completely without standing hairs. Major worker with head microsculptured and matt; luster if any very weak; with head in full-face view antennal scape not reaching posterolateral corner of head... C. sp. 72 of SKY 5. Propodeum with standing hairs over the dorsal face. In profile, petiole thin, scale-like with steep anterior slope C. arrogans - Propodeum with standing hairs only in posterior portion of its dorsum. In profile, petiole thicker with gentler anterior slope Smaller species. Minor worker mm in total length; major worker ca. 7 mm long. Clypeus of major distinctly longer than broad... C. sp. 154 of SKY - Larger species. Minor worker mm in total length; major worker more than 8 mm. Clypeus of major at most as long as broad... C. sp. 48 of SKY 33. Camponotus (Tanaemyrmex) arrogans (F. Smith) (Pl. 10, K & L) Camponotus arrogans: Wara et al. 2008: 4. This is one of the most common Tanaemyrmex in Sundaland. Two workers were collected on Rakata between Plot 3 and the summit. Dr. Rosichon net-swept some from the lower vegetation on Sertung. Aug. 2005, RK & SR (SKY & RU). 34. Camponotus (Tanaemyrmex) cleon Forel Camponotus maculatus cleon Forel: Wheeler 1924: 253, Dammerman 1929: 100. Camponotus cleon Forel: Dammerman 1948: 377. Only a winged queen was collected in Dec. 1919, Rakata (KWD). 35. Camponotus (Tanaemyrmex) festinus F. Smith Camponotus festinus eximius Emery: Wheeler 1937: 24, Dammerman 1948: 376. This large species, ranging widely in Indo-Malayan region, has never been collected from the Krakataus since Mar. 1931, Rakata (DVL); Apr. 1933, Rakata (KWD). 36. Camponotus (Tanaemyrmex) sp. 48 of SKY (Pl. 11, A D) Camponotus (Tanaemyrmex) sp. 48 of SKY: Abe et al. 2012: 68.?Camponotus maculatus irritans F. Smith: Forel 1909: 229, Dammerman 1922: 98, Wheeler 1924: 253, Dammerman 1929: 100.?Camponotus irritans F. Smith: Wheeler 1937: 24, Dammerman 1948: 377.?Camponotus irritans var. inferior Forel: Wheeler 1937: 24, Dammerman 1948: 377. Donisthorpe (1932) suggested that the types (minors) of Formica irritans may be minors of Camponotus diligens (F. Smith), which is treated by Bolton (1995) as a subspecies of C. festinus (F. Smith). Another so-called type (major) of F. irritans deposited at the Natural History Museum, London is, according to Donisthorpe (1932), not the true type. I am not sure that the true C. irritans actually occurs on the Krakataus. Camponotus irritans and C. irritans var. inferior in Dammerman s sense are very probably C. sp. 48 of SKY. Diagnosis of the minor worker based on the present material: Minor. 6 7 mm in total length. Head elongate, distinctly narrowed posteriorly, but without a neck. Clypeus broader than long, with a complete median carina. Eye slightly breaking outer margin of head, located around midlength of

14 14 head. Mandible with 6 teeth; subbasal tooth often bifid apically. Antennal scape extending beyond posterior margin of head by slightly more than half its length. Mesosoma rather elongate, in profile with dorsal outline evenly arched. Petiole in profile relatively thick, posteriorly straight, anteriorly weakly convex with short, straight basal slope. Head and entire mesosoma with microscopic superficial sculpture and weakly matt; dorsa of head, mesosoma and petiole with standing hairs, but on propodeum standing hairs confined to posterior declivity. Head, antennal scape and gaster dark brown; the rest much paler. Major. 8 9 mm in total length. Head in full-face view longer than broad, broadest slightly posteriorly to eye level, rather distinctly narrowed anteriorly, distinctly convex laterally, straight to slightly concave posteriorly. Clypeus excluding anterolateral lobes slightly longer than broad; its anterior margin very weakly and broadly emarginate. Antennal scape extending beyond posterior margin of head by slightly more than its 1/4 length. Petiole in profile with long and straight posterior slope; anterior face comprising almost straight upper slope and much shorter and vertical basal slope. Dorsal face of head including clypeus and basal half of mandible densely microsculptured and matt; lateral face of head much more weakly sculptured and weakly shiny. Entire mesosoma and petiole with dense microscopic sculpture and weakly matt. Head with numerous standing hairs over the surface; all short hairs on scape appressed; promesonotum dorsally with standing hairs; propodeal dorsum with a few standing hairs around posterior declivity; petiole with ca. 10 standing hairs; gaster covered with numerous long standing hairs. Head and antennal scape blackish brown; antennal flagellum, mesosoma, petiole and legs yellowish to reddish brown; gaster dark brown. This is a very common species on the Krakataus as well as in other parts of Sundaland. Nests were found from within rotting wood and dead twigs/branches on the ground, and from under logs (partly in soil) in the forest. Foragers were observed on Hibiscus trees near the coast on Anak Krakatau. May 1908, RK (ERJ); Dec. 1919, RK (KWD); Sept. 1920, RK (KWD); Jan., Apr. 1933, RK (KWD); Jan. 1933, SR (KWD); Apr. 1934, RK (KWD); Oct. 1982, RK & PN (TA); Aug. 2005, RK, SR, PN & AK (SKY); Jan. 2007, SR & PN (SKY). 37. Camponotus (Tanaemyrmex) sp. 72 of SKY (Pl. 11, E & F) Camponotus sp. 3: Tentative List (cf. Yamane 2005: 30). Camponotus (Tanaemyrmex) sp. 72 of SKY: Abe et al. 2012: 68. This is a species similar to C. arrogans in having a thin petiole, but has genae without standing hairs in full-face view. Only a few foragers were collected at the summit of Rakata in Oct. 1982, RK (TA); Aug. 2005, RK (SKY). 38. Camponotus (Tanaemyrmex) sp. 153 of SKY (Pl. 11, G J) Camponotus (Tanaemyrmex) sp. 153 of SKY: Abe et al. 2012: 68. In general appearance, in the worker, this species is similar to C. sp. 48 of SKY, but is much smaller in body size, and the standing hairs on the gena are very few or completely missing. This is the most common Tanaemyrmex on the Krakataus except on Anaka Krakatau, from beach forests to the forest interior. Nests were found from rotting wood, dead standing trees, dead twigs/branches/stems on the ground, and termite galleries. On Sertung foragers were seen attending extrafloral nectaries of Hibiscus trees near the beach (Pl. 6, A & B). Jul. 1982, RK & PN (SKY); Oct./Nov. 1982, RK & SR (TA); Aug. 2005, RK & SR (SKY); Dec & Jan. 2007, RK, SR & AK (SKY). 39. Camponotus (Tanaemyrmex) sp. 154 of SKY (Pl. 12, A D) Camponotus (Tanaemyrmex) sp. 154 of SKY: Abe et al. 2012: 68. This is very similar to C. sp. 48 of SKY, and distinguished from the latter by the constantly smaller body and the very long clypeus of the major worker (see key). A colony was collected in a Timonius forest on Sertung from a dead standing tree (RK05- SKY-30). Two colonies were collected on P. Sebuku; one of them nested in a decayed stump (RK05-SKY-58); the other contained males (RK05-SKY-57, 14 Aug. 2005). Nov. 1982, AK (TA); Aug. 2005, RK & SR (SKY & Syaukani). Genus Echinopla F. Smith Only a single species of this genus has been known from the Krakataus. 40. Echinopla lineata Mayr, 1862 (Pl. 12, E & F) Echinopla lineata: Abe et al. 2012: 68. Echinopla sucki Forel: Dammerman 1929: 100, Dammerman 1948: 380. This species is relatively common on Borneo, Java and Sumatra, but was collected only three times from the Krakataus. Dec. 1919, RK (KWD); Jul. 1982, PN (SKY); Nov. 1982, PN (TA). Genus Polyrhachis F. Smith This is a large tropical genus ranging from Afrotropical to Australian regions. Dammerman (1948) recorded 9 species from Krakatau by Although 12 species are listed in the Tentative List (cf. Yamane 2005) for 1982, Abe et al. (2012) could not locate specimens of two of them. During I collected only 6 species in spite of making every possible effort. Wara et al. (2008) reported two species sampled by Dr. Rosichon Ubaidillah with net-sweeping in Key to species of Polyrhachis from the Krakataus (workers) 1. Mesosoma without spines, at most with a pair of small tubercles on propodeum. Petiole with two median teeth, and a lateral tooth on each side. Body shiny black P. (Cyrtomyrma) sp. cf. lepida

15 A review of the ant fauna of the Krakatau Islands, Indonesia 15 - Pronotum and/or propodeum with pairs of spines. Petiolar teeth variable Dorsum of mesosoma laterally margined throughout Dorsum of mesosoma not margined laterally Propodeal spines long, almost as long as propodeal declivity. Long standing hairs abundant on head, mesosoma, petiole and gaster; longest hairs much longer than maximum eye length, only slightly shorter than propodeal spines P. (Chariomyrma) arcuata - Propodeal spines short denticles. Standing hairs on dorsum of body shorter, at most as long as maximum eye length Smaller species, measuring 4 5 mm in total length. Petiole without median spines; lateral spines very small, just denticles Larger species, measuring more than 6 mm in total length. Petiole with a pair of long and sharply pointed spines Gastral tergite 1 with many standing hairs. Pronotal spine triangular, apically blunt... P. (Myrma) cf. subpilosa - Gastral tergite 1 without standing hairs. Pronotal spine longer, sharply pointed apically Body entirely black. Propodeal declivity not demarcated from propodeal dorsum by a transverse carina P. (Myrma) ristemai - Legs more or less extensively reddish brown. Propodeal declivity demarcated from propodeal dorsum by a transverse carina... P. (Myrma) vindex 7. Lateral denticle of petiole more or less pointed apically P. (Myrma) illaudata - Lateral denticle of petiole bifid or truncated apically P. (Myrma) proxima 8. Head and mesosoma very coarsely and densely reticulopunctate. Pronotal and propodeal spines macropunctate in basal half... P. (Myrmhopla) armata - Head and mesosoma with different sculptures. Pronotal and propodeal spines not distinctly punctate Pronotal spine very small, triangular. Antennal flagellum and legs excluding tarisi yellowish to reddish brown [Dorsa of mesosoma and gastral tergites 1 and 2 without standing hairs. Head longer than broad.] P. (Myrmhopla) flavoflagellata - Pronotal spine longer, longer than broad at base. Antenal flagellum and legs differently colored; if colour pattern similar, then body very hairly (P. bicolor) or head distinctly braoder than long (P. caligata) Body more than 7 mm in total length. Propodeal spine slender, straight, directed posteriad P. (Myrmhopla) abdominalis - Body less than 6 mm in total length. Propodeal spine more or less directed upward Propodeal spine curved outwardly. Entire body black P. (Myrmhopla) dives - Propodeal spine straight. Gaster and/or legs orangish or reddish Gaster, legs, antenna and mandible orangish or yellowish brown. Petiole without a pair of median denticles between spines... P. (Myrmhopla) bicolor - Only legs reddish brown; other parts black. Petiole with a pair of distinct median denticles between spines P. (Myrmhopla) caligata 41. Polyrhachis (Chariomyrma) arcuata (Le Guillou, 1842) (Pl. 12, G & H) Polyrhachis sp. 1: Tentative List (cf. Yamane 2005: 30) Polyrhachis arcuata: Wara et al. 2008: 4. Polyrhachis (Chariomyrma) arcuata: Abe et al. 2012: 68. This species was first collected in 1982 from Sertung, and later in by net-sweeping (Wara et al. 2008) and handcollecting from the lower vegetation on Anak Krakatau. Nov. 1982, SR (TA); Aug. 2005, AK (RU); Dec. 2006, AK (SKY). 42. Polyrhachis (Cyrtomyrma) cf. lepida Kohout (Pl. 12, I & J) Polyrhachis rastellata Latreille: Forel 1909: 229, Dammerman 1922: 98, Wheeler 1924: 254, Dammerman 1929: 100, Tentative List (cf. Yamane 2005: 30). Polyrhachis (Cyrtomyrma) cf. lepida: Abe et al. 2012: 68. According to Kohout (2006) the holotype queen of P. rastellata was apparently lost a long time ago. The single queen specimen collected by me from the Krakataus in 2006 is very similar to the queen of P. lepida described from Borneo. This dealated queen was observed attending extrafloral nectaries of a Hibiscus tree near the coast. May 1908, PN (ERJ); Nov. 1982, PN (TA); Dec. 2006, RK (SKY). 43. Polyrhachis (Myrma) illaudata Walker, 1859 (Pl. 13, A & B) Polyrhachis (Myrma) illaudata: Abe et al. 2012: 68. Polyrhachis mayri Roger: Forel 1909: 230, Dammerman 1922: 98, Wheeler 1924: 253, Dammerman 1929: 100, Wheeler 1937: 24, Dammerman 1948: 378, Tentative List (cf. Yamane 2005: 30). This is one of the most common species of the subgenus Myrma in the Sunda region. It is distinguished from the closely related P. proxima by the apically pointed lateral denticle on petiole (in the latter the denticle is bifid or truncated at apex). In 2005 this species was collected in a forest near coast, and a nest was found from inside an epiphyte attached to a small tree near the summit of Rakata. May 1908, RK (ERJ); Sept. 1920, RK (KWD); Nov. 1932, RK (KWD); Oct. 1933, RK (KWD); Apr. 1934, RK (KWD); Jul. 1982, RK (SKY); Oct. 1982, RK (TA); Aug. 2005, RK (SKY & Syaukani); Jan. 2007, SR (SKY).

16 Polyrhachis (Myrma) proxima Roger, 1863 (Pl. 13, C & D) Polyrhachis (Myrma) proxima: Abe et al. 2012: 68. Polyrhachis proxima: Forel 1909: 230, Dammerman 1922: 98, Wheeler 1924: 253, Dammerman 1929: 100, Wheeler 1937: 24. Dammerman 1948: 378, Tentative List (cf. Yamane 2005: 30). This was common on the Krakataus until 1982, but I did not find any individual during May 1908, RK (ERJ); Dec. 1919, RK (KWD); Dec. 1933, RK & SR (KWD); Apr. 1934, RK (KWD); Jul. 1982, SR & AK (SKY); Nov. 1982, SR & PN (TA). 45. Polyrhachis (Myrma) ristemai Mayr, 1883 Polyrhachis sp. 2: Tentative List (cf. Yamane 2005: 30). Polyrhachis (Myrma) ristemai: Abe et al. 2012: 68. This is a small species very similar to P. vindex, but the body is entirely black. The posterior declivity of the propodeum is not demarcated from the dorsal face of propodeum by a transverse carina. Several species closely related to these species occur in Southeast Asia, and the taxonomy of this group is very difficult. This species was only collected from Rakata and Sertung in 1982 (queens, worker and male). Jul. 1982, SR (SKY); Oct. 1982, RK (TA). 46. Polyrhachis (Myrma) cf. subpilosa Emery, 1895 Polyrhachis (Myrma) cf. subpilosa: Abe et al. 2012: 68. Jul. 1982, AK (SKY). 47. Polyrhachis (Myrma) vindex F. Smith Polyrhachis orsyllus F. Smith: Forel 1909: 230, Dammerman 1922: 98. Polyrhachis vindex: Wheeler 1924: 254, Dammerman 1929: 100, Dammerman 1948: 378. May 1908, RK (ERJ); Sept. 1920, RK (KWD). 48. Polyrhachis (Myrmhopla) abdominalis F. Smith, 1858 (Pl. 13, E & F) Polyrhachis (Myrmhopla) abdominalis: Abe et al. 2012: 68. Polyrhachis abdominalis: Wheeler 1924: 254, Dammerman 1929: 100, Wheeler 1937: 24, Dammerman 1948: 379, Tentative List (cf. Yamane 2005: 30). This species has been most frequently encountered on Rakata among the four islands of Krakatau. Oct. 1921, RK (KWD); Nov. 1932, RK (KWD); Apr. 1933, RK (KWD); Apr. 1934, RK (KWD); Jul. 1982, RK (SKY); Oct./ Nov. 1982, RK & PN (TA); Aug. 2005, RK (SKY). throughout Southeast Asia. However, the latter is very rare on the Krakataus (in 2005 only a single dealated queen with a reddish gaster was collected on Rakata). May 1908, RK (ERJ); Aug. 2005, RK (SKY). 50. Polyrhachis (Myrmhopla) bicolor F. Smith, 1858 (Pl. 13, G & H) Polyrhachis bicolor: Jacobson 1909: 200, Forel 1909: 229, Dammerman 1922: 98, Wheeler 1924: 254, Dammmerman 1929: 100, Dammerman 1948: , Tentative List (cf. Yamane 2005: 30), Abe et al. 2012: 68. This is a common species in Southeast Asia, nesting among tree leaves in sparse forests or plantations. During the latest survey it was not seen on any of the four islets. May 1908, RK & SR (ERJ); Dec. 1919, RK (KWD); Jul. 1982, RK (SKY). 51. Polyrhachis (Myrmhopla) caligata Emery (Pl. 13, K & L)?Polyrhachis argentea Mayr: Wheeler 1924: 254, Dammerman 1929: 100, Dammerman 1948: 379. Polyrhachis caligata: Wara et al. 2008: 4. The taxonomy of the P. saevissima species group, in which P. argentea, P. caligata, P. tibialis etc. are included, is not yet completed, leaving many complicated problems (cf. Kohout, 1998, p. 517). Dammerman s P. argentea is very probably identical with my P. caligata. Dec. 1919, RK (KWD); Aug. 2005, RK, SR & AK (SKY & RU). 52. Polyrhachis (Myrmhopla) dives F. Smith, 1857 (Pl. 13, I & J) Polyrhachis (Myrmhopla) dives: Abe et al. 2012: 68. Polyrhachis dives: Jacobson 1909: 200, Forel 1909: 229, Dammerman 1922: 98, Wheeler 1924: 254, Dammerman 1929: 100, Wheeler 1937: 24, Dammerman 1948: 379, Tentative List (cf. Yamane 2005: 30). This is a very common Polyrhachis occurring in bush and other disturbed vegetation throughout tropical and subtropical Asia. On the Krakataus it had been recorded constantly from 1908 until During the 1990s many nests were observed in the coastal vegetation of Anak Krakatau (Rosichon Ubaidillah, pers. comm.; specimens not available). However, during the latest expedition from 2005 to 2007, neither nests nor individuals of this species were found from any of the four islands. The species has probably become extinct. May 1908, RK & SR (ERJ); Dec. 1919, RK (KWD); Apr. 1920, SR (KWD); Oct. 1933, RK (KWD); Dec. 1933, SR (KWD); Jul. 1982, AK (SKY); Nov. 1982, SR & AK (TA). 49. Polyrhachis (Myrmhopla) armata (Le Guillou, 1842) Polyrhachis armata: Forel 1909, 230, Dammerman 1922, 98, Dammerman 1929, 100. Polyrhachis abdominalis and P. armata are very common 53. Polyrhachis (Myrmhopla) flavoflagellata Karavaiev, 1927 (Pl. 14, A & B) Polyrhachis (Myrmhopla) flavoflagellata: Abe et al. 2012: 68. Jul. 1982, RK (SKY).

17 A review of the ant fauna of the Krakatau Islands, Indonesia 17 Subfamily PSEUDOMYRMECINAE Genus Tetraponera Dammerman (1948) recorded three species from the Krakataus. In 1982 Abe and Yamane collected two of them (T. attenuata was absent) in addition to T. allaborans that was not collected earlier (Abe et al., 2012). I collected the same two species during Key to species of Tetraponera from the Krakataus (workers) 1. Larger species, more than 6 mm in total length Smaller species, less than 5 mm in total length Ocelli present. Mesosoma, petiole and postpetiole red T. rufonigra - Ocelli absent. Body entirely black... T. attenuata 3. Mandible slender, with 3 teeth on masticatory margin and 1 2 denticles on basal margin. Petiole slender, with a distinct pedicel; in profile petiolar node with gentle anterior and posterior slopes... T. allaborans - Mandible more robust, with 4 teeth on masticatory margin and 0 1 denticle on basal margin. Petiole more robust, with a shorter pedicel; in profile petiolar node with steep anterior slope that is much steeper than posterior slope... T. nitida 54. Tetraponera allaborans (Walker, 1859) (Pl. 14, C & D) Tetraponera allaborans: Abe et al. 2012: 68. This is a common species spread over tropical and subtropical Asia to northeastern Australia (Ward, 2001), but on the Krakataus it was collected only once in 1982 by T. Abe from a Saccharum plant. Nov. 1982, AK (TA). 55. Tetraponera attenuata F. Smith Sima nigra thagatensis Forel: Forel 1909: 226, Dammerman 1922: 98. Tetraponera nigra thagatensis: Wheeler 1925: 243, Dammerman 1929: 100, 1948: 369. Tetraponera attenuata: Ward 2001: A large black species measuring around 7 mm in total body length, with a long pedicel of petiole. This is a very widespread species, ranging from northeast India and southern China to the whole Sundaland (Ward, 2001). On the Krakataus it was found only in 1908 by E. R. Jacobson. Dammerman (1948) did not notice it in the second and third survey periods. It may have become extinct because it is improbable that this conspicuous ant has been escaped from the eyes of the many entomologists who have visited the Krakataus after May 1908, RK & PN (ERJ). 56. Tetraponera nitida (F. Smith, 1840) (Pl. 14, E & F) Sima siggii Forel: Forel 1909: 226, Dammerman 1922: 98. Tetraponera siggii: Wheeler 1924: 243, Dammerman 1929: 100, 1948: 370. Tetraponera sp. (=siggii Forel?): Tentative List (cf. Yamane 2005: 30). Tetraponera nitida: Abe et al. 2012: 68. A small black species measuring less than 4 mm in total body length. May 1908, RK & SR (ERJ); Sept. 1920, RK (KWD); Oct. 1982, SR (TA); Dec. 2006/Jan. 2007, RK & PN (SKY) 57. Tetraponera rufonigra (Jerdon, 1851) (Pl. 14, G & H) Sima rufonigra Jerdon: Forel 1909: 226, Dammerman 1922: 98. Tetraponera rufonigra: Wheeler 1924: 243, Dammerman 1929: 100, Wheeler 1937: 22, Dammerman 1948: 369, Tentative List (cf. Yamane 2005: 30), Ward 2001: , Abe et al. 2012: 68. This large species with a red mesosoma and waist occurs in disturbed areas like house gardens, city parks, university campuses and shrubs in South and Southeast Asia. On the Krakataus it was common on Rakata and Sertung until mid- 1930s. However, in 1982 it was found only on Anak Krakatau in large numbers. In I did not find it on any of the four islets. The species has most probably become extinct on this island group. In 1982 this species was common in growing Casuarina forests, Saccharum grasslands and other types of shrub established near the coast of Anak Krakatau. Dammerman (1948) suggested that this species nested in the hollow stem of trees. May 1908, RK (ERJ); Dec. 1919, RK & SR (KWD); Dec. 1933, RK & SR (KWD); Apr. 1934, RK (KWD); Jul. 1982, AK (SKY); Nov. 1982, AK (TA). Subfamily CERAPACHYINAE 58. Cerapachys sp. 64 of SKY (Pl. 14, I & J) Cerapachys sp.: Tentative List (cf. Yamane: 2005) Cerapachys sp. 64 of SKY: Abe et al. 2012: 69. This is a relatively small species with a brown to reddish brown body, with the following characteristics: head width ca mm; frontal carinae confluent at the level of posterior margin of antennal insertion, posteriorly forming an elongate loop; eye invisible; propodeal declivity rather distinctly margined laterally and dorsally; petiole nearly as long as broad; postpetiole distinctly broader than long; pygidium convex dorsally; body with weak sculpture, rather smooth and shining; punctures distinct but generally sparse especially on the dorsum of petiole and postpetiole; pygidium basally smooth and apically densely punctate. This species in some respects resembles C. bryanti Wheeler described from Borneo (Wheeler 1919), but in the latter eyes are present, both the petiolar and postpetiolar nodes are anteriorly distinctly margined, and postpetiole is longer than broad. This species was collected on Sertung in 1982 for the first

18 18 time, and again found in 2005 but on Panjang. One worker of the same species was collected on Pulau Sebuku at an altitude of 400 m in August 2005 by Syaukani. A colony (RK05-SKT-160) was found in soil under a log in the forest; only workers were collected. Jul. 1982, SR (SKY); Aug. 2005, PN (SKY). Subfamily AMBLYOPONINAE 59. Prionopelta kraepelini Forel, 1905 (Pl. 15, A & B) Prionopelta kraepelini: Abe et al. 2012: 69. The worker specimens collected well agree with those from Java, the type locality of the species. This species was found on the Krakataus for the first time in 1982 from Anak Krakatau. In 2007 workers were collected in the forest on Sertung (one worker collected in a Timonius forest located in Plot 2 for vegetation study). Nov. 1982, AK (TA); Jan. 2007, SR (SKY). Subfamily PONERINAE Tribe Ponerini 60. Anochetus graeffei Mayr, 1870 (Pl. 15, C & D) Anochetus punctiventris Mayr: Wheeler 1937: 21, Dammerman 1948: 368. Anochetus sp. (=punctiventris Mayr?): Tentative List (cf. Yamane 2005: 30). Anochetus taylori For.: Wheeler 1937: 22, Dammerman 1948: 369. Anochetus graeffei: Abe et al. 2012: 69. Both Anochetus punctiventris and A. taylori are junior synonyms of A. graeffei (see Bolton, 1995). However, A. graeffei is a widespread species (type locality: Samoa) with a considerable variation in body size, sculpture and coloration, and may include some sibling species. Some nests were found from rotting wood, a dead twig and an abandoned termite nest (probably of Nasutitermes matangensis) in Nov. 1932, RK (KWD); Dec. 1937, SR (KWD); Jul. 1982, PN (SKY); Oct./Nov. 1982, RK & PN (TA); Aug. 2005, RK, PN & AK (SKY); Dec. 2006/Jan. 2007, PN (SKY). 61. Cryptopone sp. 11 of SKY (Pl. 15, E & F) Head is in full-face view slightly longer than broad. Eye is absent. Mandible has 5 teeth; the second (counted from apex) and basal teeth are much smaller than the apical, third and fourth teeth. Antennal club is clearly 4-segmented. Propodeum seen from above strongly tapers basally with the lateral margins almost straight; the basal portion just behind the metanotal groove is acutely pointed. Only one worker was collected in the Plot 3 forest on Rakata. Aug. 2005, RK (SKY). Genus Hypoponera Until recently only one species, H. confinis javana, had been recorded from the Krakataus. The most recent survey in revealed that at least seven species had arrived there. Key to species of Hypoponera from the Krakataus (workers) 1. Body large, more than 3 mm long. Eye large comprising more than 10 ommatidia... H. sp. F - Body smaller, less than 3 mm. Eye smaller, comprising less than 10 ommatidia Head and mesosoma densely punctate and almost entirely dull Head and mesosoma with weak and superficial sculpture, in profile extensively shiny Head distinctly longer than broad. Mandible extensively smooth and shiny... H. sp. C - Head almost as long as broad. Basal half of mandible punctate.... H. sp. A 4. With head in full-face view, antennal scape not passing the posterior margin of head With head in full-face view, antennal scape passing the posterior margin of head Larger species measuring more than 2.5 mm in total length. Body yellowish brown to brown. Eye distinct with 2 3 ommatidia... H. confinis javana - Smaller species measuring around 1.5 mm in total length. Body yellow. Eye almost missing... H. sp. D 6. Larger species measuring more than 2.5 mm in total length. Head as long as broad... H. sp. B - Smaller species measuring less than 2 mm in total length. Head longer than broad... H. sp. E 62. Hypoponera confinis javana Forel (Pl. 15, G & H) Ponera confinis var. javana: Wheeler 1924: 242, Dammerman 1919: 100, Wheeler 1937: 21, Dammerman 1948: 368. Hypoponera confinis (Roger)?: Tentative List (cf. Yamane 2005: 30). Hypoponera confinis javana: Abe et al. 2012: 69. A yellowish brown to brown species with yellow legs. This species has been constantly collected since 1919, and was the most common on all the four islets in On Rakata it was found from the coast to the summit. In this species was collected from Casuarina forests and other types of coastal forest, and forest interior. Many nests were found from rotting wood (partly in soil), soil under logs, and abandoned nests of the termite Nasutitermes matangensis. Foragers were collected from leaf litter and surface soil. Dec. 1919, RK (KWD); Apr. 1920, RK (KWD); Oct. 1921, SR (KWD); Aug. 1930, SR (KWD); Jan./Apr. 1933, RK & SR (KWD); Jul. 1982, RK, SR & PN (SKY); Oct./Nov. 1982, RK,

19 A review of the ant fauna of the Krakatau Islands, Indonesia 19 SR, PN & AK (TA); Aug. 2005, RK, SR, PN & AK (SKY & Syaukani); Dec. 2006/Jan. 2007, RK, SR & PN (SKY). 63. Hypoponera sp. A (Pl. 15, K & L) A colony was collected from rotting wood near the beach. Aug. 2005, SR (SKY). 64. Hypoponera sp. B (Pl. 15, I & J) Foragers were collected from leaf litter. Aug. 2005, RK (SKY). 65. Hypoponera sp. C (Pl. 15, M & N) Only one worker was collected from rotting wood in Plot 3 on Panjang. Aug. 2005, PN (SKY) 66. Hypoponera sp. D (Pl. 16, A & B) Workers were found in coastal forests and forest interior. A colony was collected from soil under a log. Aug. 2005, RK, SR & PN (SKY) 67. Hypoponera sp. E (Pl. 16, C & D) A few foragers were collected in Plot 2 and at the summit of Rakata. Aug. 2005, RK (SKY) 68. Hypoponera sp. F (Pl. 16, E & F) This species was found only in the forest interior. Colonies were collected from rotting wood and soil of a fallen tree trunk, and foragers from leaf litter and surface soil. Aug. 2005, RK & PN (SKY). 69. Leptogenys cf. peuqueti (André, 1887) (Pl. 16, G & H) Leptogenys sp.: Tentative List (cf. Yamane: 2005) Leptogenys cf. peuqueti: Abe et al. 2012: 69. Leptogenys was first found on Panjang in July 1982 by me (Abe et al., 2012), and in January 2007 it was collected again on the same island. A colony (RK07-SKY-022) was found from rotting wood in a forest. A forager was collected on a freshly fallen tree. Jul. 1982, PN (SKY); Jan. 2007, PN (SKY). 70. Myopias breviloba (Wheeler, 1919) (Pl. 16, I & J) Trapeziopelta breviloba: Wheeler 1937, 21; Dammerman 1948: 368, Abe et al. 2012: 69. Trapeziopelta breviloba?: Tentative List (cf. Yamane 2005: 30). Two winged queens were collected on Rakata in Two dealated queens from a colony collected by T. Abe in 1982 on Rakata roughly agree with the original description of M. breviloba (queen) in sculpture and coloration. Workers from the same colony are similar to the queen, with the following characteristics: head longer than broad, maximum diameter of eye nearly as long as width of antennal scape at midlength, body extensively smooth (at most superficially punctate) with lower portion of metapleuron and posterior portion of side of propodeum striate, dorsum of body with sparse standing hairs. For the moment I consider the specimens collected in 1982 to belong to the same species recorded by Dammerman (1948). Apr. 1933, RK (KWD); Oct. 1982, RK (TA). 71. Myopias sp. 11 of SKY (Pl. 16, K & L) Myopias sp. 11 of SKY: Abe et al. 2012: 69. Only three workers were available. This is similar to the preceding species, but has a slightly smaller body (3.5 mm vs mm in total length). The head is slightly longer than broad, the eyes are vestigial, and body hairs are denser and shorter than in the preceding species. Jul. 1982, RK (SKY); Oct. 1982, RK (TA); Aug. 2005, RK (SKY). 72. Odontomachus simillimus F. Smith (Pl. 16, M & N) Odontomachus haematoda Linnaeus: Wheeler 1924: 243, Dammerman 1929: 100, Wheeler 1937: 22, Dammerman 1948: 369. Odontomachus haematoda (=monticola): Tentative List (cf. Yamane 2005: 30). Odontomachus simillimus: Abe et al. 2012: 69. This is a very common species found in disturbed areas, including sparse secondary forests, roadsides, residential areas etc. throughout Southeast Asia. It has been constantly collected on the Krakataus from 1919 to 2007, but its colonisation of Anak Krakatau was first confirmed in On the Krakataus this species inhabits the forest interior. Nests were found in rotting wood, under logs and from leaf litter/surface soil. Dec. 1919, RK (KWD); Sept. 1920, RK (KWD); Jan. 1933, SR (KWD); Apr. 1933, RK (KWD); Dec. 1933, SR (KWD); Jul. 1982, RK, SR & PN (SKY); Oct./Nov. 1982, RK & SR (TA); Aug. 2005, RK, SR, PN & AK (SKY & Syaukani); Jan. 2007, SR (SKY). 73. Odontoponera denticulata (F. Smith) (Pl. 17, A & B) Odontoponera transversa F. Smith: Wheeler 1924: 242, Dammerman 1929: 100, Wheeler 1937: 21, Tentative List (cf. Yamane 2005: 30). Odontoponera denticulata: Abe et al. 2012: 69. Recently O. denticulata was separated from O. transversa based on consistent morphological differences in the worker and queen (Yamane, 2009). The former prefers more disturbed and open sites, spreading into a wide range in tropical Asia, while the latter prefers good forests and is confined to Sundaland. All the Odontoponera specimens sampled in 1982 and are O. denticulata. Although I did not examine the specimens collected by K.W. Dammerman, these are probably O. denticulata.

20 20 In I collected this species in sparse beach forests on Rakata and Sertung. Iwamoto (1986) found this species (referred to as O. transversa) from the stomach of the skink Mabuya multifasciata Kuhl on Rakata. Dec. 1919, RK (KWD); Sept. 1920, RK (KWD); Oct. 1921, RK (KWD); Nov. 1932, RK (KWD); Apr. 1933, RK (KWD); Jul. 1982, RK & SR (SKY); Oct./Nov. 1982, RK, SR & AK (TA); Aug. 2005, RK & SR (SKY). 74. Pachycondyla (Brachyponera) cf. sp. 28 of SKY Euponera luteipes Mayr: Forel 1909: 221, Dammerman 1922: 98, Wheeler 1924: 242, Dammerman 1929: 100, Wheeler 1937: 21, Dammerman 1948: 368. Brachyponera sp. (=luteipes Mayr?): Tentative List (cf. Yamane 2005: 30). Pachycondyla (Brachyponera) cf. sp. 28 of SKY: Abe et al. 2012: 69. This belongs to the subgenus Brachyponera, which is a very difficult group in taxonomy. The specimens collected in 1982 and are closely related to P. chinensis (Emery) rather than to P. luteipes (Mayr). However, unlike P. chinensis, the mandible of these specimens lacks an elongate groove near its base. Specimens collected in 1982 well agree with those collected in I tentatively treat all the specimens recorded from the Krakataus as belonging to one and the same species. Although K.W. Dammerman collected this species from Sertung in 1933, all the other specimens came from Rakata. Intensive survey by me in 2005 did not record this species from Sertung. Foragers and colonies were collected from leaf litter and surface soil in the forest interior. May 1908, RK (ERJ); Dec. 1919, RK (KWD); Apr. 1920, RK & SR (KWD); Jan./Apr./Dec. 1933, RK (KWD); Jan./Dec. 1933, SR (KWD); Jul. 1982, RK (SKY); Oct. 1982, RK (TA); Aug. 2005, RK (SKY). Genus Ponera This genus was collected from the Krakataus in November, 1982 by T. Abe for the first time. In 2005 two species were collected by me. 75. Ponera sp. A (Pl. 17, E & F) Ponera sp.: Tentaive List (cf. Yamane, 2005: 30). Ponera sp. A: Abe et al. 2012: 69. A small species measuring slightly more than 1 mm in total length. Body is dark reddish brown, with the dorsa of the head and gaster darker. Clypeus, mandible, antenna and legs are yellowish. Major portion of the body is finely punctate, but the posterior faces of the propodeum and petiole extensively smooth, and the lateral faces of the mesosoma are only weakly sculptured and shining; the punctation on the head is very fine and dense. Eye is very small, comprising a single ommatidium. With the head in full-face view the antennal scape does not reach the dorsal margin of the head. Petiole has an evenly arched anterior margin and almost straight posterior margin in dorsal view. Three workers were collected in Plot 3 and at the summit of Rakata in Oct. 1982, RK (TA); Aug. 2005, RK (SKY). 76. Ponera sp. B (Pl. 17, G & H) Slightly smaller than P. sp. A, measuring around 1 mm in total length. Head is distinctly longer than broad. With the head in full-face view the antennal scape does not reach the posterior margin of the head. Eye is very small, comprising a single ommatidium. Head is very finely and closely punctate; in other parts of the body the punctation is sparser and superficial; the mesosoma and the dorsum of the petiole almost smooth. Body is yellowish brown, with the antennal flagellum and legs paler. A worker was collected in a Casuarina forest on Anak Krakatau. A winged queen, probably of this species, was collected in another site of the island. Aug. 2005, AK (SKY). Tribe Platythyreini 77. Platythyrea parallela (F. Smith) (Pl. 17, I & J) The Tentative List includes Probolomyrmex (?) sp. collected by T. Abe in November 1982 from Rakata. I could not locate the specimen(s). There is the possibility that his Probolomyrmex (?) sp. is actually Platythyrea parallela. Three workers were collected near the coast and in the forest interior. Aug. 2005, RK (SKY); Dec. 2006, RK (SKY). Subfamily MYRMICINAE Ogata et al. in their unpublished report to the Japan Society for Promotion of Science listed the genus Meranoplus from the Krakataus (the collection site is not mentioned). However, I could not locate the specimens of this genus in the Ogata Collection at Kyushu University, and have accordingly excluded this genus from the present list. Tribe Dacetini Until the 1930s only one species of Dacetini, Strumigenys godeffroyi Mayr, had been recorded from this island group. The same species was collected in Ogata et al. (2001) recorded Pyramica and Strumigenys collected in 2000, but the species were not identified. In I collected two Pyramica and two Strumigenys species. They were identified using keys provided by Bolton (2000). Although the synonymy of Pyramica under Strumigenys is now widely accepted (Bolton, 2013), here I retain the traditional system.

21 A review of the ant fauna of the Krakatau Islands, Indonesia Pyramica dohertyi (Emery) (Pl. 17, K & L) This is a widespread and common species. On the Krakataus only three workers were collected in forests on Rakata and Panjang. Aug. 2005, RK & PN (SKY). 79. Pyramica karawajewi (Brown) (Pl. 17, M & N) Only one worker and two dealated queens were collected from leaf litter and surface soil in the forest. Aug. 2005, RK (SKY). 80. Strumigenys emmae (Emery) (Pl. 18, A & B) A small species with a broad head provided with modified hairs and short curved mandibles. This is a famous tramp species found all over the warmer regions of the world (Bolton, 2000). Workers were found from soil and under a log in the coastal Casuarina forest and forest interior. Aug. 2005, SR & AK (SKY); Dec. 2006/ Jan. 2007, SR (SKY). 81. Strumigenys godeffroyi Mayr, 1866 (Pl. 18, C & D) Strumigenys godeffroyi (?): Tentative List (cf. Yamane 2005: 30). Strumigenys godeffroyi: Wheeler 1937: 23, Dammerman 1948: 373, Wara et al. 2008: 4, Abe et al. 2012: 69. This is easily distinguished from the previous species by its larger body, more elongate head with simple hairs, and almost entirely smooth and shining metapleuron and side of propodeum. This also might be a tramp species, found from a wide range of Old World tropics and Oceania. It occurs on all the four islets of the Krakataus. In many colonies were collected from under logs (partly in soil) and rotting wood. A colony was located in an abandoned termite nest. Foragers were also collected from leaf litter. Apr. 1933, RK (KWD); Jul. 1982, RK (SKY); Oct. 1982, RK (TA); Aug. 2005, RK, SR, PN & AK (SKY, RU & Syaukani); Dec. 2006, SR (SKY). Tribe Stenammini 82. Lordomyrma sp. 3 of SKY (Pl. 18, E & F)? Pristomyrmex sp.: Tentative List (cf. Yamane 2005: 30) Lordomyrma sp. 3 of SKY: Abe et al. 2012: 69. This is a relatively small species of Lordomyrma, measuring 2.5 mm in total length. Whole body reddish brown. A colony (RK05-SKY-189) was found from rotting wood at Plot 3 on Rakata. Jul. 1982, RK (SKY); Aug. 2005, RK (SKY). 83. Vollenhovia sp. 70 of SKY (Pl. 18, G & H) This is a small, dark reddish brown species, measuring less than 2 mm in total length. Entire dorsa of the head, mesosoma and waist are densely micropunctate or differently sculptured, and matt. A colony (RK05-SKY-138) was found from rotting wood near the coast on Sertung. Aug. 2005, SR (SKY). Tribe Solenopsidini Genus Monomorium Until the 1930s two species of Monomorium had been recorded from the Krakataus (Dammerman, 1948). Abe and Yamane collected three species in 1982 (Abe et al., 2012). I collected five species in 2005, and Wara et al. (2008) also recorded five species sampled by net-sweeping in Key to species of Monomorium from the Krakataus (workers) 1. Mesopleuron and lateral face of propodeum entirely or extensively punctate and matt Mesopleuron and lateral face of propodeum largely smooth and shiny, at most with a few punctures Entire dorsum of head densely punctate... M. pharaonis - Dorsum of head smooth and shiny except in anterior 1/3, where there are fine striae... M. destructor 3. Eye very small, only as long as antennal segment 9. Body almost entirely yellow (partly brownish). Propodeal declivity with lateral carinae... M. cf. sechellense - Eye much larger, much longer than antennal segment 9, even longer than segment 11. Propodeal declivity without carinae Head yellow to pale brown. Mesosoma yellow M. sp. 1 of SKY - Head brown to dark brown. Mesosoma yellow or brown Body distinctly bicolorous; head and gaster dark brown; mesosoma yellowish brown. Petiolar pedicel very distinct.... M. floricola - Body more unicolorous dark brown; mesosoma slightly paler. Petiolar pedicel relatively short... M. cf. monomorium 84. Monomorium destructor (Jerdon, 1851) (Pl. 18, I & J) Monomorium pharaonis: Tentative List (cf. Yamane 2005: 30). Monomorium destructor: Wara et al. 2008: 4, Abe et al. 2012: 69. This is a polymorphic species, with a deep metanotal groove and a long pedicel of the petiole. This is a famous tramp ant, known from tropical and subtropical areas of the world. It was collected on the Krakataus for the first time in 1982 from Sertung and Anak Krakatau. During it was common on Rakata and Anak Krakatau. A colony (RK05-SKY-144) was found from rotting wood on Anak Krakatau. Workers were seen foraging on the lower vegetation, including Saccharum spontaneum L. grasses. Jul. 1982, AK (SKY); Nov. 1982, SR & AK (TA); Aug. 2005, RK & AK (RU & SKY); Dec. 2006, AK (SKY).

22 Monomorium floricola (Jerdon, 1851) (Pl. 18, K & L) Monomorium floricola: Tentative List (cf. Yamane 2005: 30); Wara et al. 2008: 4, Abe et al. 2012: 69. This is also a famous tramp ant found throughout tropical and subtropical areas of the world. On the Krakataus it was first collected in 1982, and very common during I collected workers from a colony nesting in rotting wood very close to the coast (Sertung). Workers and several dealated queens were observed moving to a new nest site on the beach (Rakata). Foragers were net-swept from the lower vegetation (Wara et al., 2008), and observed being attracted to powdered cheese baits. Oct./Nov. 1982, RK & PN (TA); Aug. 2005, SR, PN & AK (SKY & RU); Dec. 2006/Jan. 2007, RK, SR & PN (SKY). 86. Monomorium cf. monomorium Bolton, 1987 (Pl. 18, M & N)?Monomorium minutum liliuokalanii javanum Forel: Forel 1909: 225, Dammmerman 1922: 98, Wheeler 1924: 246, Dammerman 1929: 100, Dammerman 1948: 371.?Monomorium minutum: Tentative List (cf. Yamane 2005: 30). Monomorium cf. monomorium Bolton: Abe et al. 2012: 69. The type locality of M. minutum Mayr (i.e., of M. monomorium, the replacement name for M. minutum) is Italy, and that of M. liliuokalanii is Hawaii. I did not examine the type material, but here I tentatively use the name M. cf. monomorium for the Krakatau population. M. monomorium is a famous tramp species recorded from over the world. May 1908, RK (ERJ); Jul. 1982, SR (SKY); Oct./Nov. 1982, RK & AK (TA); Aug. 2005, RK, SR & AK (SKY); Dec. 2006, RK & AK (SKY). 87. Monomorium pharaonis (Linnaeus, 1758) Monomorium pharaonis: Wheeler 1924: 246, Dammerman 1929: 100, Wara et al. 2008: 4. This is also a famous tramp species, of which the place of origin is unknown. However, it was not collected in 1982, and not common during on the Krakataus, being found only from Sertung in small numbers (Wara et al., 2008). Sept. 1920, RK (KWD); Oct. 1921, SR (KWD); Jan. & Apr. 1933, RK & SR (KWD); Aug. 2005, SR (RU). 88. Monomorium cf. sechellense Emery, 1894 Monomorium sechellense: Wara et al. 2008: 4. Only a few workers were collected from leaf litter and surface soil on Rakata. Some others were sampled from the lower vegetation with net-sweeping on Anak Krakatau. Aug. 2005, RK & AK (SKY & RU). 89. Monomorium sp. 1 of SKY (Pl. 19, A & B) Monomorium sp. 5: Wara et al. 2008: 4. This small yellow species is common throughout Southeast Asia. It was collected from the lower vegetation by net-sweeping, and from leaf litter/ surface soil in the forest. Aug. 2005, RK (RU & SKY). Genera Oligomyrmex and Solenopsis These small ants were never collected until recently. The famous tramp Solenopsis geminata (Fabricius, 1804) has never been collected on the Krakataus. Tentative List (cf. Yamane, 2005) gave a species of Pheidologeton, which, however, proved to be Monomorium destructor. Although recently Oligomyrmex was synonymized with Carebara (Fernández, 2004), Oligomyrmex is retained in this paper. 90. Oligomyrmex sp. 33 of SKY (Pl. 19, C F) Minor worker small, less than 1 mm in total length. Head rectangular; antennal scape slightly extending beyond midlength of head; eye very small consisting of one or slightly more ommatidia. Propodeal spines absent. Entire body smooth and shining and yellowish. Collected from a Casuarina forest near the coast. Aug. 2005, AK (SKY). 91. Solenopsis sp. 1 of SKY (Pl. 19, G & H) A small species, the worker measuring only 1 mm. Body colour is paler than the next species. A colony (RK05-SKY-171) was collected from rotting wood in the forest, containing many dealated queens. Aug. 2005, RK (SKY). 92. Solenopsis sp. 15 of SKY Solenopsis sp. 15 of SKY: Abe et al. 2012: 70. Body slightly smaller than 1.5 mm in total length, yellowish brown with darker gaster. Workers were collected from soil in forests. Two colonies were found on Anak Krakatau, one from soil (RK05-SKY-129) and the other from a dead twig on the ground (RK05-SKY-125), both containing many males. Oct./Nov. 1982, RK, SR & AK (TA); Aug. 2005, AK (SKY); Dec. 2006, PN (SKY). Tribe Tetramoriini Two genera, Tetramorium and Rhoptromyrmex, have been known from the Krakataus. Dammerman (1948) reported four species of Tetramorium. Abe and Yamane collected the same four species in 1982 (Abe et al., 2012). Taylor (1992) recorded two species of Rhoptromyrmex collected from Anak Krakatau in During the survey of I collected five Tetramorium species, two of which are new to Krakatau, and a Rhoptromyrmex species. 93. Rhoptromyrmex rawlinsoni Taylor, 1992 (Pl. 19, I & J) Rhoptromyrmex rawlinsoni Taylor, 1992:

23 A review of the ant fauna of the Krakatau Islands, Indonesia 23 This species was described based on a single alate queen collected with a water trap by a member of the 1985 expedition led by Prof. I.W.B. Thornton, Australia. Taylor (1992) suspected this species to be a workerless parasite. Although the anteriorly produced clypeus is said to be one of the main characteristics of this species, this condition is also seen in the worker of R. sp. 3 of SKY from Borneo and Java. The worker specimens collected in 2005 on Anak Krakatau matches well with the specimens from Borneo and Java. Although I do not have the queen caste of sp. 3 of SKY, I tentatively regard the Krakatau specimens as the worker of R. rawlinsoni. If my treatment is correct, then this species is not a workerless parasite. A colony was collected from a dead standing tree (RK05- SKY-143). Aug. 1985, AK (I.W.B. Thornton team); Aug. 2005, AK (SKY). 94. Rhoptromyrmex wroughtonii Forel, 1902 Rhoptromyrmex wroughtonii: Taylor 1992: 127. No detailed data are available. Taylor (1992) considered this species to be a possible host of the preceding species. Aug. 1985, AK (I.W.B. Thornton team). Key to species of Tetramorium from the Krakataus 1. Dorsum of head and mesosoma with bifid and trifid hairs mixed with simple hairs... T. lanuginosum - Dorsum of body lacking branched hairs Entire body dark brown... T. pacificum - Body yellowish brown to brown Dorsum of mesosoma with sparse hairs of uniform length that are apically truncated (usually less than 15 hairs) T. simillimum - Dorsum of mesosoma with denser hairs of variable length that are apically tapering (more than 20 hairs) Petiole with a long pedicel that is as long as node; anterodorsal corner of petiolar node in profile round. Anterior margin of clypeus entire... T. tonganum - Petiole with a shorter pedicel; anterodorsal corner of petiolar node in profile angled, with a distinct anterior slope. Anterior margin of clypeus medially indented Mandible almost smooth. Some of standing hairs arising from frontal carina longer than maximum eye length T. cf. insolens - Mandible distinctly striate over the surface. Hairs arising from frontal carina shorter than maximum eye length T. bicarinatum 95. Tetramorium bicarinatum (Nylander, 1846) (Pl. 19, K & L) Tetramorium guineense Fabr.: Wheeler 1937: 23, Dammerman 1948: 372. Tetramorium bicarinatum: Tentative List (cf. Yamane 2005: 30), Wara et al. 2008: 4, Abe et al. 2012: 70. This is a famous tramp species found throughout tropical and subtropical areas of the world. Until the 1930s this species has been found only on Rakata and Sertung (Dammerman 1948), but in 1982 it was common on all the islands except on Rakata. Also in it was absent on Rakata. Foragers were seen attracted to powdered-cheese baits and extrafloral nectaries of Hibiscus trees on Anak Krakatau. Apr. & Sept. 1920, RK (KWD); Jan. 1933, RK & SR (KWD); Jul. 1982, SR & AK (SKY); Nov. 1982, SR, PN & AK (TA); Aug. 2005, SR, PN & AK (SKY & RU); Dec. 2006, SR, PN & AK (SKY). 96. Tetramorium cf. insolens (F. Smith, 1861) (Pl. 19, M & N) Tetramorium cf. insolens: Abe et al. 2012: 70. This is a yellowish species related to T. bicarinatum, but the mandible is extensively smooth. Tetramorium cf. insolens has been collected only from Sertung and Panjang. Jul. 1982, SR (SKY); Nov. 1982, SR & PN (SKY); Aug. 2005, SR (SKY) 97. Tetramorium lanuginosum Mayr, 1870 (Pl. 20, A & B) Triglyphothrix lanuginosa Mayr: Wheeler 1924: 251, 1937: 23, Dammerman 1948: 372. Triglyphothrix?lanuginosa: Tentative List (cf. Yamane 2005: 30). Tetramorium lanuginosum: Wara et al. 2008: 4, Abe et al. 2012: 70. This species is a common tramp found all over the world, but on the Krakataus it was not collected until 1933 (Dammerman, 1948). In it was one of the most common Tetramorium species, but absent on Rakata. Tetramorium lanuginosum was seen in both beach forests and forest interior. Nests were found from under stones, rotting wood and dead standing trees. Workers were attracted to powdered-cheese baits. Foragers were sampled from the lower vegetation (Wara et al., 2008) and also seen on tree trunks. Apr. 1933, RK (KWD); Jul. 1982, AK & SR; Oct. 1982, RK & SR (TA); Jul. 2005, SR, PN & AK (SKY, RU & Syaukani). 98. Tetramorium pacificum Mayr, 1870 (Pl. 20, E & F) Tetramorium (?) spec.: Jacobson 1909: 251. Tetramorium pacificum: Forel 1909: 225, Dammerman 1922: 98, Wheeler 1924: 251, Dammerman 1929: 100, 1948: 373, Tentative List (cf. Yamane 2005: 30), Wara et al. 2008: 4, Schlick-Steiner et al., 2006: 182, Abe et al. 2012: 70. This is a very common species ranging from Tonga through Indonesia, Philippines, Malaysia and Thailand to southern China (Schlick-Steiner et al., 2006). It is also common on the Krakataus. Its close relative, T. scabrum Mayr, is confined to Sundaland, and was found on Pulau Sebesi, one of the stepping

24 24 stones between the Krakataus and South Sumatra (Schlick- Steiner et al., 2006). In Tetramorium pacificum was collected in both beach forests and forest interior. Several nests were found from dead twigs of living or dead trees near the beach of Rakata. Other nests were found from dead twigs and rotting wood on Sertung and Panjang. Foragers were net-swept from the lower vegetation (Wara et al., 2008). Dammerman (1948, p. 151) wrote another very common species was a Tetramorium (pacificum?) which also makes papery nests on stalks and twigs when explaining the ant fauna on Rakata associated with grasslands of Saccharum in 1908 citing Jacobson s report. This may be a misidentification because there is no Tetramorium species in Asia constructing carton nests. May 1908, RK (ERJ); Sept. 1920, RK (KWD); Jul. 1982, SR (SKY); Oct./Nov. 1982, SR & PN (TA); Aug. 2005, SR & PN (SKY, RU); Nov. 2006/Jan. 2007, RK, SR & PN (SKY). 99. Tetramorium simillimum (F. Smith, 1851) (Pl. 20, C & D) Tetramorium simillimum: Abe et al. 2012: 70. This is also a famous tramp species but was not found before 1982 on the Krakataus. A colony (RK06-SKY-015) was found from a dead twig trapped on a tree. Other workers were collected from rotting wood in a forest. Nov. 1982, AK (TA); Dec. 2006, PN (SKY) Tetramorium tonganum Mayr, 1870 Tetramorium tonganum: Wheeler 1937: 23, Dammerman 1948: 373. Tetramorium?tonganum: Wara et al. 2008: 4. This is also a widespread tramp species but is rather rare, and on the Krakataus only known from Rakata. The Tentative List recorded this species from Rakata in October/November, 1982 (cf. Yamane 2005, p. 30) but the specimen(s) has not been located. Wara et al. (2008) net-swept foragers, probably of this species, on Rakata. Apr. 1933, RK (KWD); Aug. 2005, RK (RU). Tribe Pheidolini Only the genus Pheidole has been recorded from the Krakataus. Dammerman (1948) listed 4 species, and T. Abe collected 8 species in 1982 (Tentative List). I collected 8 species during , and Dr. Rosichon added one species by netsweeping. Key to species from the Krakataus based on minor workers 1. Head and mesosoma entirely or extensively punctate, reticulate or differently sculptured [Smaller species, measuring around 1.5 mm in total length.] Head and mesosoma entirely or largely smooth and shining [Body size variable from 1.5 mm to 2.5 mm.] Longitudinal carinae dominant on dorsum of head; venter of head extensively smooth. With head in full-face view antennal scape much extending far beyond posterior margin of head... P. sp. A - Dorsum of head very densely punctate, longitudinal carinae if any not dominant. With head in full-face view antennal scape at most only slightly extending beyond posterior margin of head Head and mesosoma blackish brown. Metanotal groove with several strong longitudinal carinae... P. verlatensis - Head and mesosoma yellowish brown to brown. Longitudinal carinae on metanotal groove fewer or weaker Area just ventral to eye rather distinctly sculptured and matt. Gastral tergite 1 entirely smooth and shiny... P. sp. B - Area just ventral to eye only superficially sculptured and shiny. Basal half of gastral tergite 1 covered with dense irregular sculpture and matt... P. miseranda 5. Petiole very high, much higher than postpetiole; the height greater than the length of petiolar pedicel... P. sauberi - Petiole as high as or only slightly higher than postpetiole Smaller species measuring only mm in total length. With mesosoma in profile mesonotum without a dorsal prominence behind pronotum. Maximum eye length larger than the length of antennal segment Larger species, usually more than 2.5 mm in total length. With mesosoma in profile mesonotum with a prominence behind pronotum. Maximum eye length smaller than the length of antennal segment Larger species, measuring around 2.0 mm in total length. Node of petiole dorsoventrally flattened, seen from above as long as or even longer than broad... P. megacephala - Smaller species, measuring slightly larger than 1.0 mm in total length. Node of postpetiole very short, seen from above much broader than long Posterolateral corner of head distinctly sculptured. Body yellowish brown... P. hortensis - Posterolateral corner of head smooth and shining. Body brown to dark brown, with antenna, legs and waist paler P. dammermani 9. Dorsum of head superficially sculptured with weaker luster. Pronotal side weakly sculptured... P. plagiaria - Dorsum of head and pronotal side smooth and very shining Dorsum of propodeum clearly punctate and dull... P. fervens - Dorsum of propodeum with superficial transverse striae, rather shining... P. cf. oceanica 101. Pheidole cf. dammermani Wheeler, 1924 (Pl. 20, G J) Pheidole cf. dammermani: Abe et al. 2012: 70. A minor and major from Panjang were identified by Dr. K. Eguchi as Pheidole umbonata Mayr, a species principally known from New Guinea and Polynesia. However, the longitudinal carinae of the dorsum of the soldier head are more developed

25 A review of the ant fauna of the Krakatau Islands, Indonesia 25 in the present material than in the Polynesian specimens (see Fig. 36 in Wilson and Taylor 1967). Pheidole dammermani, originally described from P. Sebesi of the Sunda Straits, may be closely related to P. umbonata. My material mostly agrees with the descriptions of the types by Wheeler (1924), but the minor workers are much darker in coloration than the single minor he used. It is possible that the minor was teneral so that body was not yet fully pigmented. This species was common on the Krakataus except on Rakata, but I got only one minor from P. Sebesi, the type locality of P. dammermani. This species was seen from sparse coastal forests to the forest interior. Foragers were collected from the lower vegetation and forest floor including leaf litter, and also attracted to powdered-cheese baits. Nests were found from rotting wood, dead twigs, and soil. A winged queen was collected from KR05- SKY-162 on 18 August Jul. 1982, SR (SKY); Nov. 1982, SR & PN (TA); Aug. 2005, SR, PN & AK (SKY); Dec. 2006/Jan. 2007, SR, PN & AK (SKY) Pheidole fervens F. Smith, 1858 Pheidole fervens: Wara et al. 2008: 4, Abe et al. 2012: 70. Minor worker measures slightly larger than 2.0 mm, and the major worker 2.5 to 3.0 mm in the specimens from P. Sebesi. This species widely ranges through tropical and subtropical Asia, and is common on P. Sebesi located between the Krakataus and Sumatra. On the Krakataus it was collected only three times on Rakata. Jul. 1982, RK (SKY); Oct. 1982, RK (TA); Aug. 2005, RK (RU) Pheidole hortensis Forel, 1913 Pheidole hortensis: Wheeler 1937: 22, Dammerman 1948: 370. This minute species is common throughout Sundaland (Eguchi, 2001), but was only once met with, in 1933, on the Krakataus. Apr. 1933, RK (KWD) Pheidole megacephala (Fabricius, 1793) Pheidole megacephala: Wheeler 1924: 243, Dammerman 1929: 100, Wheeler 1937: 22, Dammerman 1948: 370. This famous tramp species was collected only on Sertung during It probably became extinct before the 1980s. Dec. 1919, SR (KWD); Oct. 1921, SR (KWD); April & Dec. 1933, SR (KWD) Pheidole miseranda Wheeler, 1924 (Pl. 20, K N) Pheidole miseranda Wheeler, 1924: , Dammerman 1929: 100 (major worker), Wheeler 1937: 23 (minor worker), Dammerman 1948: 370, Bolton 1995: 325, Abe et al. 2012: 70. A small species, measuring slightly less than 1.5 mm in the minor worker and slightly more than 2.0 mm in the major worker. The minor and major specimens collected in well agree with the descriptions by Wheeler (1924, 1937) except that the postpetiole and first gasteral tergite (especially in the anterior half) of the minor are minutely sculptured and dull (according to Wheeler these portions are smooth and shining). Head of the minor is dorsally minutely and densely punctate. Hypostoma of the major has three median processes, but the condition of the central one varies even within single colonies (central one is always smaller than the lateral ones, but occasionally even vestigial) This is a typical forest inhabitant, nesting in rotting wood. Foragers were collected from leaf litter, and attracted to powdered cheese baits. Dec. 1919, RK (KWD); Apr. 1933, RK & SR (KWD); Dec. 1933, SR (KWD); Nov. 1982, SR, PN & AK (TA); Aug. 2005, SR & PN (SKY); Dec. 2006, RK, SR & PN (SKY) Pheidole cf. oceanica Mayr, 1866 (Pl. 21, A D) Pheidole cf. oceanica: Wara et al. 2008: 4, Abe et al. 2012: 70. A major and minor from Panjang were identified by Dr. K. Eguchi as P. sp. cf. oceanica. This species is similar to P. fervens in the size of the major and minor, and is separated in the minor caste from the latter by the sculpture on the propodeal dorsum (see the key). In the major, however, this species is quite different from P. fervens in having the following features: longitudinal carinae present between the frontal carinae (ca. 10 carinae in the latter), posterior portion of dorsum of head irregularly and coarsely reticulate (the area with longitudinal carinae that are more regular throughout the length in the latter), prominence on mesonotum produced as an angle in profile (low and evenly rounded in the latter; see Eguchi, 2001, Fig. 16C), and lateral face of propodeum striate, with a few punctures (extensively evenly punctate in P. fervens). This is a common forest inhabitant, observed from sparse beach forests to the forest interior. Nests were found from rotting wood, dead twigs and abandoned termite (Nasutitermes) nests. Foragers were collected from the lower vegetation and leaf litter, and also attracted to powdered-cheese baits on the forest floor. Colony RK06-SKY-11 (28 Dec. 2006) collected from Panjang contained males and winged queens. Jul. 1982, RK (SKY); Oct./Nov. 1982, RK, SR, PN & AK (TA); Aug. 2005, RK, SR, PN & AK (SKY, RU & Syaukani); Dec. 2006/Jan. 2007, PN (SKY) Pheidole plagiaria F. Smith, 1860 (Pl. 21, E H) Pheidole plagiaria: Eguchi 2001: 88 91, Wara et al. 2008: 4, Abe et al. 2012: 70. This is the largest species among the Krakatau Pheidole, ca. 2.5 mm in the minor and mm in the major. Antenna and legs bear numerous long standing hairs. Hairs on the dorsa

26 26 of the head and mesosoma are very long. This species is common throughout Southeast Asia, but is not abundant on the Krakataus. Two colonies were found on Rakata (rotting twig) and on Panjang (rotting wood). Jul. 1982, RK, PN & AK (SKY); Nov. 1982, PN (TA); Aug. 2005, RK (SKY); Dec. 2006, PN (SKY) Pheidole sauberi Forel, 1905 (Pl. 21, I L) Pheidole sauberi: Wara et al. 2008: 4, Abe et al. 2012: 70. A major and minor from Panjang were identified by Dr. K. Eguchi as P. sauberi. This small species has an exceptionally high petiolar node among the Krakatau Pheidole. It is known from the Philippines and Sundaland. This species inhabited forests and nested in rotting wood. A winged queens and males were collected on Panjang on 18 August 2005 (RK05-SKY-165). Oct./Nov. 1982, RK & PN (TA); Aug. 2005, RK, SR & PN (SKY & RU) Pheidole nodgii verlatensis Wheeler, 1937 (Pl. 21, M P) Pheidole nodgii verlatensis Wheeler 1937: 22, Dammerman 1948: 370, Abe et al. 2012: 70. The major workers collected by me well agree with the original description by Wheeler, particularly in the condition of the posterior emargination of the head, the pronotal shape, and the length of the propodeal spines. The ground colour is not black as mentioned by Wheeler, but dark reddish brown (Dammerman, 1948, described it as blackish brown). This species was sampled from leaf litter in the forest. Nests were commonly observed in rotting wood, dead twigs and rotting stumps. Jan. 1933, SR (KWD); Nov. 1982, RK, SR (TA); Aug. 2005, RK, SR & PN (SKY); Dec. 2006/Jan. 2007, RK, SR & PN (SKY) Pheidole sp. A Pheidole sp. A: Abe et al. 2012: 70. Similar to P. miseranda in the minor, but the venter of the head extensively smooth. Head has parallel longitudinal carinae densely, with the interspaces densely punctate. Antennal scape is long, extending beyond the posterior margin of the head by a length of the antennal segment 10. Dorsum of the pronotum has several longitudinal carinae. Dorsum of the postpetiole is smooth and shining. Only two workers were collected near the coast of Ralata. Oct. 1982, RK (TA); Dec. 2006, RK (SKY) Pheidole sp. B Pheidole sp. B: Abe et al. 2012: 70. In the major worker collected in 1982, the hypostoma has a pair of median processes. Two minor workers collected in 1982 and 2006 are very similar to the minors of P. nodgii and P. tjibodana. Lateral face of the head is almost entirely punctate and dull. Dorsum of the head and the entire mesosoma are closely punctate. Head, mesosoma and waist are yellowish brown; the antenna and legs are yellow. Oct. 1982, RK (TA); Dec. 2006, RK (SKY). Tribe Crematogastrini Dammerman (1948) recorded three species (5 forms) of Crematogaster. Abe and Yamane collected four species in 1982 (Abe et al., 2012); specimens of all of them were located this time. Six species were collected by me during the latest survey from 2005 to Dr. Shingo Hosoishi of Kyushu University kindly identified some of the specimens. The subgeneric system was drastically changed by Blaimer (2012), leaving only two subgenera, Crematogaster and Orthocrema. All Krakatau species other than C. baduvi belong to the subgenus Crematogaster. Key to species of Crematogaster from the Krakataus (workers) 1. Antennal club 2-segmented. Petiole distinctly longer than broad, parallel-sided. Propodeal spine very long, longer than the dorsum of propodeum, strongly diverging C. baduvi - Antennal club 3- or 4-segmented, or the club indistinct. Petiolar shape variable. Propodeal spine usually shorter than the dorsum of propodeum, not strongly diverging Antennal club 4-segmented or the club indistinct. Propodeum produced posterolaterally so that its declivity deeply concave... C. sewardi - Antennal club 3-segmented. Propodeum normal Dorsum of head largely densely striate......c. dohrni/rogenhoferi - Dorsum of head largely smooth, shining Dorsum of mesosoma extensively smooth and shining; sculpture if any superficial Dorsum of mesosoma largely sculptured Dorsum of mesosoma without standing hairs. Propodeal spines very widely separated from each other; distance between their bases as long as pronotal width C. cf. treubi - Dorsum of mesosoma with sparse long standing hairs. Distance between the bases of propodeal spines much shorter than pronotal width... C. ferrarii 6. Antennal scape and hind tibia with abundant standing hairs. Pronotum usually separated from mesonotum by a transverse carina... C. sp. 39 of SKY - Antennal scape and hind tibia at most with a few standing hairs. Pronotum continuous with mesonotum, without a transverse carina between them...c. jacobsoni 112. Crematogaster (Crematogaster) ferrarii Emery, 1888 (Pl. 22, A & B) Crematogaster ferrarii: Wheeler 1924: 245, Dammerman 1929: 100, Wheeler 1937: 23, Dammerman 1937: 370, Tentative

27 A review of the ant fauna of the Krakatau Islands, Indonesia 27 List (cf. Yamane 2005: 30), Abe et al. 2012: 70. Body length varies from 1.5 to 3.0 mm. This species is characterized by the following features: antennal scape and hind tibia with long erect/suberect hairs, dorsa of mesosoma and waist almost entirely smooth and shining, and longitudinal furrow on postpetiole indistinct in its anterior half. This belongs to the subgenus Crematogaster in the traditional sense. In most specimens were collected in sparse forests near the coast. Foragers were found on the lower vegetation, or attending extrafloral nectaries of Macaranga trees on Anak Krakatau. Workers were also attracted to powdered-cheese baits. No nests were located. Dec. 1919, RK (KWD); Oct. 1921, SR (KWD); Apr. 1933, SR (KWD); Oct. 1933, RK (KWD); Jul. 1982, SR (SKY); Oct. 1982, RK (J. Yukawa); Oct. 1982, SR (TA); Aug. 2005, RK, SR & AK (SKY); Dec. 2006, SR & AK (SKY) Crematogaster (Crematogaster) jacobsoni Forel, 1911 (Pl. 22, C & D) Some specimens collected from Sertung were identified as C. jacobsoni by Dr. S. Hosoishi. This is a small species measuring mm in total length. Among the present material the size variation is small. Hairs on the antennal scape and hind tibia are short and decumbent (only a few on the scape are suberect). Clypeus has weak longitudinal striae. Mesosoma is strongly margined laterally. Propodeal spine is relatively short and thick. Petiole is much wider than long; the postpetiole is smooth dorsally, and has a distinct longitudinal furrow. This belongs to Crematogaster in the traditional sense. Foragers were found on the lower vegetation and tree trunks, and also from leaf litter. No nests were located. Aug. 2005, SR (SKY); Dec. 2006/Jan. 2007, RK & SR (SKY) Crematogaster (Crematogaster) dohrni artifex Mayr, 1879 Crematogaster artifex Mayr: Forel 1909: 225, Dammerman 1922: 98. Crematogaster dohrni artifex: Wheeler 1924: 246, Dammerman 1929: 100, 1948: 371. This belongs to Crematogaster in the traditional sense. May 1908, RK (ERJ) Crematogaster (Crematogaster) rogenhoferi Mayr, 1879 Crematogaster dohrni rogenhoferi: Wheeler 1937: 23, Dammerman 1948: 371. Crematogaster dohrni rogenhoferi ver. fabricans Forel: Wheeler 1924: 246, Dammerman 1929: 100, Dammerman 1948: 371. According to Bingham (1903) C. rogenhoferi is distinguished from C. dohrni by the longer propodeal spines, which are distinctly longer than the propodeum. C. rogenhoferi is, however, a highly polymorphic species with considerable variation in body sculpture, the length of the propodeal spine, the shape of the petiole, and coloration. It is quite possible that the three forms recorded by Dammerman (1948) belong to the same species. This wide-ranging species should be seriously revised taxonomically. This belongs to Crematogaster in the traditional sense. Recent materials of Crematogaster from the Krakataus do not contain specimens of this complex, which might have become extinct because the large arboreal nest of C. rogenhoferi is so conspicuous that it should not have escaped entomologists eyes if present. Dec. 1919, RK (KWD; fabricans); Sept. 1920, RK (KWD; fabricans); Apr. & Oct. 1933, RK (KWD; typical & fabricans) Crematogaster (Crematogaster) sp. 39 of SKY (Pl. 22, E & F) Crematogaster (Crematogaster) sp. 39 of SKY: Abe et al. 2012: 70. According to Dr. S. Hosoishi this species matches C. sp. Sh 20. Body length is mm, without considerable size variation. Pronotal dorsum has several longitudinal carinae, and separated from the closely punctate mesonotum by a transverse carina, which is rarely obsolete. This belongs to Crematogaster in the traditional sense. This species was seen in forests from the coastal area to the summit of Rakata. Foragers were collected from the lower vegetation and leaf litter. Jul. 1982, RK (SKY); Oct./Nov. 1982, RK & AK (TA); Aug & Dec. 2006, RK & PN (SKY) Crematogaster (Crematogaster) cf. sp. 77 of SKY (Pl. 22, G & H) This species, measuring 2.5 mm long in total body length, is easily separable from the other Crematogaster species from the Krakataus by the lack of standing hairs on the dorsum of the mesosoma. Body extensively smooth and shining. Mesosoma is very short, broader than long; the pro-mesonotal suture is very weak. Propodeal spines are very widely spaced from each other. Petiole is as broad as long, broader anteriorly than posteriorly. Postpetiole is as broard as the petiole, with a shallow median furrow. This belongs to the subgenus Oxygyne in the traditional sense. Only one worker was collected from the lower vegetation in a forest. Dec. 2006, RK (SKY) Crematogaster (Crematogaster) sewardi Forel, 1901 (Pl. 22, I & J) Crematogaster deformis F. Smith: Wheeler 1924: 246, Dammerman 1929: 100, Wheeler 1937: 23, Dammerman 1948: 371, Tentative List (cf. Yamane, 2005: 30). Crematogaster (Crematogaster) difformis F. Smith: Wara et al. 2008: 4.

28 28 Crematogaster sewardi: Hosoishi 2009: 28 29, Abe et al. 2012: 70. Specimens collected during the surveys were identified by Dr. S. Hosoishi as C. sewardi (see Hosoishi, 2009). The older records of C. deformis by Dammerman (1948) are considered to represent C. sewardi because the forest condition in the earlier phase of the recolonisation should have been poorer than now. Crematogaster sewardi inhabits more disturbed or seasonal forests compared with the rainforest counterpart C. difformis F. Smith. This belongs to the subgenus Physocrema in the traditional sense. This is wide-spread throughout Southeast Asia, and common in the Krakataus and currently seen on all the four islands. Many foragers were collected from the ground surface and lower vegetation. Nests were located in the decayed part of living trees. Winged queens were collected on 30 Dec (Sertung) and 1 Jan (Rakata). Sept. 1920, RK (KWD); Aug. 1930, SR (KWD); Oct. 1933, RK (KWD); Jul. 1982, RK, SR & PN (SKY); Nov. 1982, SR, PN & AK (TA); Aug. 2005, RK, SR, PN & AK (SKY & RU); Dec. 2006/Jan. 2007, RK, SR, PN & AK (SKY) 119. Crematogaster (Ortocrema) baduvi Forel, 1912 (Pl. 22, K & L) Crematogaster sp. 1: Tentative List (cf. Yamane 2005). Crematogaster (subgen. indet.) baduvi: Abe et al. 2012: 70. Some workers from Rakata were identified by Dr. S. Hosoishi as C. baduvi. This species is currently included in the subgenus Orthocrema (e.g., Bolton, 1995). Although the 2-segmented antennal club, narrow petiole, and unfurrowed postpetiole give this species an affinity to Orthocrema, Dr. Hosoishi suggested that its taxonomic position should be revised. This is a slender and uniformly dark brown species with the mandible and antennal club yellowish. This species is widely distributed in Sundaland. On the Krakataus it has been found only on Rakata in 1982 and Foragers were collected in forests from the coastal area to the summit of Rakata. They were observed being attracted to Hibiscus extrafloral nectaries. A colony (RK06-SKY-046) was located in the decayed part of a small tree. A winged queen was collected on 20 August 2005 by Dr. Syaukani probably from a colony. Jul. 1982, RK (SKY); Oct. 1982, RK & PN (TA); Aug. 2005, RK (SKY & Syaukani). Tribe Liomyrmecini 120. Liomyrmex gestroi (Emery, 1887) (Pl. 22, M & N) Liomyrmex sp.: Tentative List (cf. Yamane 2005: 30). Liomyrmex gestroi: Abe et al. 2012: 70. Rigato and Bolton (2001) recognised only one species in this genus. The Krakatau specimens collected by T. Abe agreed well with specimens identified by Dr. F. Rigato. This small blind species was only once collected on the Krakataus in 1982 from Rakata and Panjang. Oct./Nov. 1982, RK & PN (TA). Tribe Formicoxenini Genus Cardiocondyla Emery Dammerman (1948) did not list any species of this genus. T. Abe collected two species in November 1982 (cf. Yamane, 2005), but specimens of only one of them were located (Abe et al., 2012). In I collected 4 species that can be keyed out below. Seifert (2003) reviewed the Asian species (including tramp species) of this genus, still leaving many problems. Cardioconlyla nuda (Mayr) and C. emeryi Forel that appeared in papers dealing with Sundaland ant fauna in the past may be, in most cases, C. cf. kagutsuchi Terayama and C. tjibodana Karavaiev respectively. The true C. kagutsuchi has so far been known only from the Southern Ryukyus, Japan (Mamoru Terayama, pers. comm.). Key to species of Cardiocondyla from the Krakataus (workers) 1. Propodeal spine short and more or less triangular, at most as long as its basal width. Head and mesosoma yellowish to reddish brown Propodeal spine linear, much longer than its basal width. Head and mesosoma yellow to pale yellowish brown Smaller species measuring slightly more than 1 mm in total length. Head and mesosoma more yellowish. Propodeal spine apically acute... C. tjibodana - Larger species measuring more than 1.5 mm in total length. Head and mesosoma darker, reddish brown. Propodeal spine reduced, blunt at apex... C. sp. cf. kagutsuchi 3. Propodeal spine very long, as long as anterior slope of petiole including pedicel. Metanotal groove almost absent C. sp. 5 of SKY - Propodeal spine much shorter, only as long as pedicel of petiole. Metanotal groove distinct... C. wroughtonii 121. Cardiocondyla cf. kagutsuchi Terayama, 1999 (Pl. 23, A & B) Cardiocondyla kagutsuchi was described from Japan, and is probably different from the form occurring in Sundaland. Dr. M. Terayama and co-workers are revising the Japanese species of this group. The Sundaland species has often been treated as C. nuda (Mayr), which is actually confined to Polynesia, New Guinea and Australia (Seifert, 2003). Two workers were collected in PHPA cottage on Sertung. Aug. 2005, SR (SKY) Cardiocondyla tjibodana Karavaiev, 1935 (Pl. 23, C & D) Cardiocondyla tjibodana: Wara et al. 2008: 4, Abe et al. 2012: 74. This species has often been identified as C. emeryi Forel, which is principally an African species (Seifert, 2003).

29 A review of the ant fauna of the Krakatau Islands, Indonesia 29 Only a few workers were collected by me on Sertung in Dr. Rosichon Ubaidillah net-swept this species from lower vegetation (Wara et al., 2008). This species seems not to be common on the Krakataus. Oct./Nov. 1982, RK & AK (TA); Aug. 2005, SR (SKY) & AK (RU) Cardiocondyla wroughtonii (Forel, 1890) (Pl. 23, E & F) This tramp species was collected from lower vegetation on Anak Krakatau, and in any sense not common. Dec. 2006, AK (SKY) Cardiocondyla sp. 5 of SKY (Pl. 23, G & H) This species has exceptionally long propodeal spines. I have specimens of this species from Borneo, Java, Singapore and the Malay Peninsula. Workers were collected in the Plot 2 forest on Rakata. Aug. 2005, RK (SKY). Tribe Myrmecinini 125. Myrmecina sp. A (Pl. 23, I & J) A small species measuring only 2.0 mm. Ogata et al. (2001) also recorded the genus Myrmecina, but did not mention the species name. A single worker was collected in the forest from leaf litter. Aug. 2005, RK (SKY) Pristomyrmex brevispinosus Emery, 1887 (Pl. 23, K & L) Pristomyrmex?brevispinosus: Tentative List (cf. Yamane 2005: 30). Pristomyrmex brevispinosus: Wheeler 1937: 23, Dammerman 1948: 372, Abe et al. 2012: 74. In 2005, several workers were collected in forests from Plot 3 to the summit of Rakata, and a single worker from Plot 1 of Panjang. Jul. 1982, RK (SKY); Oct./Nov. 1982, RK & PN (TA); Aug. 2005, RK & PN (SKY & Syaukani). DISCUSSION The Krakatau Islands have been considered a natural experiment that can serve to test some ideas in the theory of island biogeography proposed by MacArthur and Wilson (1963, 1967). Many field workers have been inspired by their theory. However, it might be noted that some ideas in their theory are seen in the somewhat lengthy discussion by Dammerman (1948). Thornton (1992) identified some of Dammmerman s statements that directly pertain to the island equilibrium theory. The central point of the theory is the presence/absence of an equilibrial species number for a given island corresponding to its area and distance from the source area. Thornton (1996) reviewed the colonisation curves of different animal and plant groups to determine whether an equilibrium had been reached in any group of organisms on the Krakataus. Although no sign of flattening was observed in the colonisation curves of higher plants or of some animal groups, he appreciated the heuristic value of MacArthur and Wilson s theory of island biogeography. In contrast Bush and Whittaker (1993) and Whittaker (2004) emphasised the limitations of the model and suggested that there may be different outcomes depending on the life history characteristics and position in the ecological hierarchy of the taxa considered, and on the disturbance regime of the system. Actual and cumulative species numbers The actual species numbers of ants for the five survey periods are plotted for the whole Krakataus (Fig. 2), and Rakata and Anak Krakatau separately (Fig. 3). Surveys on Sertung and Panjang have been incomplete compared with those on Rakata and Anak Krakatau. In the colonisation curve for the whole Krakataus no sign can be seen of approaching an equilibrium species number even in The slopes between the survey periods are almost equal throughout (Fig. 2). For Rakata, which is the most frequently surveyed island, the curve has a slightly different shape, the slope between the second and fourth survey periods being rather gentle compared with those between the first and second, and between the fourth and fifth (Fig. 3). The actual species number increased more rapidly in the latest interval. This is in contrast with the case for the social bees, social wasps and vespoid solitary wasps where equilibria seem to have been reached by 1982 (Yamane, 1983), but the curves even dropped between 1982 and (Goukon, 2008; Ikudome, 2008). The pattern for the ants is more similar to that seen in the higher plants, but the slope for later periods is much steeper in the ants than in the latter (cf. Whittaker et al. 1992, Fig. 4). MacArthur and Wilson (1967) saw similar things in the data presented by Dammerman (1948) and Docters van Leeuwen (1936). For resident birds the curve had already stopped rising by around 1932, with a species number (ca. 30) expected by the area-species curve given in MacArthur and Wilson (1963) for Actual and cumulative numbers Years from 1883 Fig. 2. Actual species (circles) and genus (squares) numbers, and cumulative species(triangles) number of ants for the whole Krakataus.

30 30 Actual species numbers the land and fresh-water birds of the Sunda group, Philippines and New Guinea, while the numbers of species in different plant groups were all increasing steadily. They suggested two possible ways to explain this pattern of plant colonisation: 1) the pool of plant species on Java and Sumatra is so enormous that the depletion effect is not visible, or 2) the extinction curve actually declined with species buildup. Both could also apply to the case of ants. The second point was criticised by Bush and Whittaker (1993) because MacArthur and Wilson s supplementary model (their Fig. 23) is not supported by empirical data. In my opinion the rates of immigration and extinction are actually very difficult to estimate since both pseudopersistences and pseudoturnovers are a common occurrence. Furthermore, we do not know what happened between the survey periods; intervals were often so long (e.g., that between the period 3 and 4 being almost 50 years). I would like to emphasize here that the ants are more passive in dispersal, and more dependent on chance than are wasps and bees, suggesting a slower and longer process needed to reach any equilibrium. Plants are generally also passive colonisers compared with birds (see also Gorman, 1979, p. 12). On Anak Krakatau again the actual species number of ants was steadily increasing (Fig. 4). Since Anak Krakatau is located at the center of this island group, it has a higher probability of Actual species number Years from 1883 Fig. 3. Actual species numbers of ants for Rakata (circles) and Anak Krakatau (squares) Years after 1883 Fig. 4. Actual species numbers of Formicinae (circles), Myrmicinae (squares) and Ponerinae (triangles). receiving immigrants from all directions more effectively than the other islands (see below). If there is no drastic vegetation change Anak Krakatau will achieve its temporary equilibrium in the near future because of its very small area that can be populated by organisms. It will also maintain actual species numbers that are slightly higher than the expected equilibrium species number, due to immigaration rates that are considered high enough to compensate for extinction rates on the island. The cumulative number in a given area counts all the species that have been recorded there at least once in the past, and most local lists of plants and animals present this kind of species number. In the most recent survey ( ) on the Krakataus the cumulative species number of ants was 125. It is difficult to evaluate this as high or low because we do not have an accurate idea of the numbers of ant species in Java and Sumatra. Ito et al. (2001) reported 216 ant species from the Bogor Botanical Garden located in the downtown of Bogor city, West Java, based on their intensive surveys made in 1982 and From Borneo, the third largest island in the world with extraordinarily rich biodiversity, Pfeiffer et al. (2011) listed 717 species and 52 additional subspecies of ant that have taxonomically valid names (naturally there should be many more unidentified and unnamed species). We can expect that the cumulative number of ant species will steadily increase on the Krakataus if the vegetation in West Java (especially Ujung Kulon, P. Panaitan and P. Peucang) and southern Sumatra, both important source areas, is not fatally damaged. Change in species composition Species found only during early sucssesional phases: Abe et al. (2012) analysed the change in ant species composition until 1982 as follows: Five species, Paraparatrechina emarginata, Camponotus (Tanaemyrmex) cleon, Polyrhachis (Myrmhopla) armata, Tetraponera attenuata, and Crematogaster (Crematogaster) dohrni, were collected only once or twice during the two early survey periods (1908 and ). It is not certain that these species became extinct before 1930s. Except for the first two, they are inhabitants of forest edges, sparse forests and bushes, and generally very common and easily witnessed if present. For example, P. armata is a large species, nesting in tree trunks or thickets of foliage and its presence is easily detected. Crematogaster dohrni constructs globular carton nests on trees or in bushes. Tetraponera attenuata is a relatively large species running on the ground or tree trunks in the daytime. They might have been lost on the Krakataus accidentally or through the reduction of suitable habitat. It could be suggested that the food source was not enough to support these species that form huge colonies (P. armata was again found in in small numbers). However, Anoplolepis gracilipes and Oecophylla smaragdina, which both also construct large nests, have persisted throughout the five

31 A review of the ant fauna of the Krakatau Islands, Indonesia 31 survey periods until now. Around half the species (10) collected in 1908 belonged to Camponotus and Polyrhachis, genera mainly composed of forest inhabitants in the Asian tropics. Eight of them were Polyrhachis. Polyrhachis dominated the young vegetation on Rakata not only in species number but also in abundance (Jacobson, 1909; Dammerman, 1948, p. 367). The ratio of Polyrhachis species to the total number of ant species fluctuated through the entire sequence: 8 (38%) in the first survey period, 7 (21%) in the second, 4 (10%) in the third, 10 (14%) in the fourth, and 6 (6%) in the fifth. Only in the fourth survey period was the actual number of species higher than in the first survey period, and the ratio of Polyrhachis species to the total number of ant species has never been as high as in the first survey. This seems strange since the actual number of Polyrhachis species is generally expected to increase with the development of forests. However, the cumulative number of Polyrachis species for the Krakataus is 12 (10% of the whole fauna), comparable to the proportions for the Bogor Botanical Garden (25 spp., 12%) (Ito et al., 2001) and Lambir Hills National Park, Borneo (54 spp., 11%) (Yamane, unpublished). It is remarkable that 80% of the Krakatau formicine genera had already arrived in the first two periods, only Acropyga arriving later by the fourth survey period. This is in contrast with the Myrmicinae, in which 67% of genera were found as late as the last two survey periods (Table 2). Some species have been more or less constantly found from 1908 or to 1982, persisting on Rakata and/ or Sertung for a long time. This category includes Anoplolepis gracilipes, Oecophylla smaragdina, Camponotus (Myrmamblys) bedoti, Camponotus (Tanaemyrmex) sp. 48 of SKY, Polyrhachis (Myrma) illaudata, Polyrhachis (Myrma) proxima, Polyrhachis (Myrmhopla) abdominalis, Tetraponera nitida, Hypoponera confinis javana, Odontomachus simillimus, Odontoponera denticulata, Pachycondyla (Brachyponera) sp. 28 of SKY, Tetramorium bicarinatum, Tetramorium pacificum, Pheidole miseranda, and Crematogaster (Physocrema) sewardi (Abe et al., 2012). Eleven of these were already collected in the first survey and found also in the last. This means that the survival of species is not a purely random process, but that particular species tend to be more persistent in a given environment than others. It is also important to note that most of these are more or less associated with forests or forest edges but do not necessarily need good forests. It is not surprising that some of them have expanded their ranges to include all four islands in later periods. Wilson (1969) proposed the concept of assortative species equilibrium that occurs after interactive species equilibrium in which the competition between species reduces the number of species present in densely populated conditions. Under the assortative phase some species may persist longer either because they are better adapted to peculiar local conditions, or else because they are able to coexist longer with a particular set of species. The present data suggest that this process can work even from the beginning, not necessarily after the interactive phase. Species that have recently arrived: The actual number of ant genera has been increasing, but the slope was naturally much less steep than that for species (Fig. 2). However, of the 39 genera recorded in were newcomers, and of the 43 genera recorded in seven were newcomers (Table 2). Some of them are genera commonly with tramps or species adapted to disturbed areas (Iridomyrmex, Ochetellus, and Cardiocondyla). This means some such species arrived in the Krakataus as late as 100 years or more after the extinction of biota (see also Fig. 5 for tramp species). Most others were forest inhabitants, belonging to Ponerinae and Myrmicinae. Figure 4 shows colonisation curves with different patterns (Formicinae, Myrmicinae and Ponerinae). In the Myrmicinae, the increase in species number is more or less constant with similar slopes between the five survey periods (the slope for the last is slightly steeper). The curve for the Formicinae has been fluctuating, with a high species number at the first survey period; the slope between the third and fourth periods is similar to that for the Myrmicinae but the slope between the fourth and fifth periods was even negative. In contrast the increase in species number for the Ponerinae between the fourth and fifth survey periods was very large owing to the sudden increase in Hypoponera (1 sp. to 7 spp.). Hypoponera is a large genus in the Asian tropics, and more species will likely arrive onto the Krakataus in the future. Turnover and vegetation succession: Abe et al. (2012) pointed out that three species inhabiting disturbed areas, namely Chronoxenus wroughtonii, Polyrhachis dives and Tetraponera rufonigra, were found mainly on Rakata and Sertung in the three survey periods from 1908 to 1934, but were found only on Anak Krakatau in 1982 (Figs. 6 & 7). Paratrechina longicornis shows a similar pattern. This shift in range can be explained by the reduction of disturbed habitat along with the growth of forests on Rakata, Sertung and Fig. 5. Occurrence of tramp species on the Krakataus throughout the five survey periods. I, 1908; II, ; III, ; IV, 1982; V,

32 32 Table 2. Occurrence of ant genera on the Krakatau Islands throughout the five survey periods. Genus Subfamily Total Bothriomyrmex D Anoplolepis F Paratrechina F Oecophylla F Camponotus F Polyrhachis F Tetraponera PS Pachycondyla PN Monomorium M Tetramorium M Crematogaster M Technomyrmex D Nylanderia F Paraparatrechina F Echinopla F Hypoponera PN Odontomachus PN Odontoponera PN Pheidole M Philidris D Tapinoma D 1* Pseudolasius F Anochetus PN Myopias PN Strumigenys M Dolichoderus D Iridomyrmex D Acropyga F Cerapachys C Prionopelta A Leptogenys PN Poner PN Lordomyrma M Solenopsis M Rhoptromyrmex M Liomyrmex M 1 4 Cardiocondyla M Pristomyrmex M Ochetellus D 1 1 Cryptopone PN 1 1 Platythyrea PN 1 1 Pyramica M 1 1 Vollenhovia M 1 1 Oligomyrmex M 1 1 Myrmecina M 1 Numerals in columns are the number of species collected. *: Iridomyrmex krakatauae in Dammerman (1948). A, Amblyoponinae; C, Cerapachyinae; D, Dolichoderinae; F, Formicinae; M, Myrmicinae; PN, Ponerinae; PS, Pseudomyrmicinae.

33 A review of the ant fauna of the Krakatau Islands, Indonesia 33 shrub layer. Any insect species with a small population size would have become extinct by this kind of disturbance. The two ant species became extinct most probably through repeated volcanic eruptions that brought about lava flows and thick layers of fallen ash. In the case of species still surviving on other islands, the recolonisation of Anak Krakatau may be relatively easy, but by 1982 P. dives and T. rufonigra had already become extinct on the other islands. Anak Krakatau may be an important refugium for species adapted to disturbed conditions, but it is too small and unstable to maintain all these species for a long time. Anyway most of the turnover events that have so far been observed on the Krakataus may represent displacements of species along with vegetation succession (cf. Thornton, 1996, p. 247). Fig. 6. Occurrence of Tetraponera rufonigra on the Krakataus throughout the periods. Fig. 7. Occurrence of Polyrhachis dives on the Krakataus throughout the periods. Panjang. Similar examples come from bird and reptile species (Dammerman, 1948; Thornton, 1996, pp ). By 1933 Rakata had been almost completely covered by trees with scattered open sites, while Anak Krakatau emerged in 1930 generating disturbed habitats. Polyrhachis dives and Tetraponera rufonigra were rather common during 1982 on Anak Krakatau (the former was abundant also in the 1990s; Rosichon Ubaidillah, pers. comm.). However, in these were not found on any island (Figs. 6 & 7). In 2005 Dr. Rosichon checked the coastal vegetation where a lot of nests of P. dives had been observed by him in the 1990s, but failed to locate even one worker ant. A supposed reason for their disappearance is that on Anak Krakatau the vegetation is confined to isolated small areas along the coast and has been repeatedly destroyed by the eruption. The volcanic activity that started in November of 1992 lasted several years and destroyed the coastal vegetation, especially the sapling and Fauna of Anak Krakatau: The volcanic activity of Anak Krakatau was first recorded in December 1927, and a small island, called Anak Krakatau I, appeared above the sea in January 1928 but disappeared afterward. After continuous volcanic activity in August 1930 an island, called Anak Krakatau IV, finally appeared that has persisted until now. Volcanic activity has continued on this island, providing spaces for new biota and also repeatedly destroying them, as well as vegetation on neighbouring islands. Anak Krakatau is important particularly in maintaining young vegetation along the coast that has harboured pioneer species driven from other islands with the growth of thick forests. In May 1929, some participants of the Fourth Pacific Science Congress landed on Anak Krakatau II and picked up only a large black cricket and a dealate queen of Prenolepis taylori that were completely desiccated and shriveled owing to the sun-baked sand. The soil sampled in 1932 contained a few species of fungus, bacterium and alga. Some plants were seen along the coast but disappeared shortly due to eruptions. In 1933 Dammerman again saw a few plants belonging to beach vegetation (Dammerman, 1948). Throughout that survey period researchers encountered only a small number of animals including insects, infrequently, and most were considered to be temporary visitors from the neighbouring islands. Dammerman (1948) mentioned three species of ant (Technomyrmex albipes, Prenolepis taylori and Camponotus variegatus) in his List of insects found on Anak Krakatau (p. 61). However, in his Taxonomic part the last species was not listed (pp for Camponotus). Anyway, during the third survey period ( ) there was no sign of ants having established their colonies on Anak Krakatau. In 1982 a total of 35 plant species were recorded from Anak Krakatau (Tagawa et al., 1986). According to Suzuki et al. (1995) that year vegetation cover was seen mainly in the north and east foreland of the island, and between these were scattered small patches of vegetation along the coast. Imperata cylindrica (L.) Raeusch. formed dense grasslands, surrounded by sparse

34 34 Casuarina equisetifolia L. and Saccharum spontaneum L. patches, but a vast area was barren (Pl. 1 B). As many as 35 ant species were collected in 1982 (Abe et al., 2012) (Fig. 3). This number is almost the same as that collected on Sertung (32) and Panjang (35) (Table 1). This is partly because Anak Krakatau was more intensively surveyed in relation to its very low vegetation cover. Although eight species (ca. 23%) were tramps, around seven were species more or less associated with trees or bushes. No species of Macaranga or Mallotus, many members of which have extrafloral nectaries (EFNs), was confirmed, though another EFN plant, Hibiscus tiliaceus, was abundant (Tagawa et al., 1986). The last species may have been used as an energy source by ants (Pl. 6, A C). It is noteworthy that forestfloor inhabitants like Prionopelta kraepelini and Hypoponera confinis were collected. These species are, in other places, generally collected from soil samples or by pitfall trapping (e.g., Ito et al., 2001) but not necessarily in the thick forest. Fuminori Ito (pers. comm., 2012) suggested that P. kraepelini nests in dead (or decayed) wood. Although no vegetation survey was made in on Anak Krakatau, it was noted the vegetation was still at an early stage due to the effect of frequent eruptions (Pl. 1, A & C). Vegetation cover was probably less than 10% of the island surface, but I also saw a richer flora with rather tall Casuarina trees (Pl. 1, D & E). The EFN tree Macaranga tanarius was abundant (Pl. 5, F). The actual number of ant species was 40, of which only slightly more than half (22) had also been collected in Thirteen species found in 1982 were not collected in , while 18 collected in the latter period were lacking in the former period. The apparent turnover rate was very high (41), and this figure may be meaningful. Dacetine genera Pyramica and Strumigenys, leaf-litter inhabitants, were met with for the first time on Anak Krakatau. It is interesting that the actual number (40 spp.) was again almost the same as that for Panjang (41), and only slightly lower than that for Sertung (47) (Table 1). This means that the number of ant species was not correlated with the development of vegetation. Again, the closeness of the four islands to each other may also facilitate frequent traffic of any kind of insect between them (Yamane, 1983). Anak Krakatau is located at the center of this island group, occupying the best position to receive animals and plants from all the directions. The high turnover rate on this island (41; 26 for the whole Krakataus) in only 24 years between the 4th and 5th periods is comparable to those observed in resident birds in the Channel Islands off California in 50 years (mean for nine islands: 36) (Diamond, 1969). Tramp species During the early successional phase Rakata, Sertung and Panjang provided suitable environment for pioneer plants and animals (Dammerman, 1948). Among these were some tramp ant species. However, some tramp species were confirmed there only during later survey periods (Fig. 5). In this paper tramp status was determined mainly based on McGlynn (1999) and Schultz and McGlynn (2000) (see also Wilson and Taylor, 1967). In total 16 tramp species are recognised among the ant fauna of the Krakataus. Some other species, such as Dolichoderus thoracicus, Tetraponera rufonigra, Polyrhachis dives, Hypoponera confinis, Strumigenys godeffroyi, and Crematogaster rogenhoferi could also be counted among tramp species, though they are not regarded as such by the authorities on tramp ants. These ants are probably native to tropical Asia, but have a very wide range of distribution, and are often found outside their natural range. In 1908 Edward Jacobson collected 21 ant species, of which only three were tramps. The proportion of tramp species in different survey periods has been relatively constant: 14% (3/21) in 1908, 18% (6/34) in , 18% (7/39) in , 16% (13/81) in , and 15% in (15/99). On the Thousand Islands Archipelago, located off Jakarta, West Java, Rizali et al. (2010) found that islands with boat docks or human settlements had significantly more tramp species than did islands lacking these factors. Using the observed species numbers, the ratio of the tramp species to the total species ranged among the 18 islands from 18% to 43% (mean=28.5%); the tramp species accounted for 21% as a whole (10 against the total 48 species). On the Krakataus tramp species accounted for 15% (15/99) in , less than the mean for the Thousand Islands (28.5%), but close to the value for the whole of the latter island group (20.8%), and also to those for some islands of this island group that are located farthest from Java and uninhabited by humans (e.g., 18% for Nyamplung, 21% for Dua Timur). The similar proportions may reflect the facts that human activities have been trivial on the Krakataus, while most islands in the the Thousand Islands Archipelago have been heavily damaged by human activities; but at the same time the Thousand Islands Archipelago has an older and more intact ant fauna on some islands retaining good forests. The famous tramp species Pheidole megacephala that was seen during the early stages of the survey became extinct after Although P. parva and Solenopsis geminata are possible candidates to replace P. megacephala, they have never been collected on the Krakataus. The status of Anoplolepis gracilipes as an invasive species on the Krakataus is not clear. This species occurred on all the Krakatau Islands, and dominated a lowland forest on Rakata in August However, during December 2006 and January 2007 its population density seemed very low in the forest on Rakata mentioned above, though it was again found on every island along the coast. Other famous tramp species, Monomorium pharaonis, M. destructor, M. floricola and Paratrechina longicornis, were not common or even rare (also see Wara et al., 2008). Anyway, this island group is not very favorable to aliens, which will finally be confined to frequently disturbed coastal belts in small numbers.

35 A review of the ant fauna of the Krakatau Islands, Indonesia 35 Food sources No detailed study has been made of food sources of ants on the Krakataus. Jacobson s statement that ants were one of the most abundant animals when he visited Rakata and Sertung in 1908 sounds surprising if most ants were predators. The vegetation was still very simple, the ground surface being predominantly covered with grass jungles composed of Saccharum spontaneum and Pennisetum macrostachyum (Brongn.) Trin. together with smaller herbs. However, in around 1896 visitors to Rakata and Sertung had already seen spiders, flies, bugs, beetles and butterflies. Jacobson also observed many spiders and centipedes. Although the fauna as a whole was poor, as many as 192 insect species were already confirmed in 1908 (Jacobson, 1909). Many of these insects could have been potential prey for ants. The number of insect species became more than three times as large (620) in 1921, and thereafter steadily increased. Of the 21 ant species recorded by Jacobson (1909), seven belonged to the genus Polyrhachis. Only the same number of Polyrhachis species was collected in which is surprising because the three old islands were almost completely covered with forests that should have provided ideal habitats to Polyrhachis species. Most Polyrhachis species found in 1908 generally prefer bushes and disturbed forests. The dietary habits of these species are not well understood. They are no doubt attracted to honeydew and plant nectar, but are rarely observed transporting prey. I strongly suspect that these ants have microbes fixing nitrogen so that any deficiency in protein food does not prevent them from inhabiting habitats with poor flora and fauna (cf. Russell et al., 2009). If this is true, pioneer herbivorous ants can colonise vegetation in early succession before the arrival of sufficient prey invertebrates that support a predator population. Since 1933 ants should have had enough protein food (Pl. 6, E). In addition to protein food, carbohaydrate food was also available even only 15 years after the catastrophic eruption. Trees with extrafloral nectaries (EFN plants) such as Macaranga tanarius and Hibiscus tiliaceus were found as early as 1896 (see below). In some coccids and nectar-bearing tree and herb flowers (e.g., Morinda citrifolia L., Rubiaceae) as well as EFN plants were seen along the beach, and were used by some ants such as Anoplolepis gracilipes and Camponotus (Tanaemyrmex) spp. (Pl. 5, C G; Pl. 6, A C). It should be noted that honey and nectar can be obtained more easily in open sites and sparse vegetation. This means that tramp ants also prevail in early successional phases dominated by grasslands and shrubs (see above). Symbiosis with plants The obligate plant-ant groups such as Crematogaster subgenus Decacrema (Myrmicinae), Cladomyrma (Formicinae) and Camponotus subgenus Myrmoplathys (Formicinae) are not distributed in Java (e.g., Agosti et al., 1999; Quek et al., 2007). Since some species of these groups are known in Sumatra, their immigaration to the Krakataus from Sumatra is likely to occur. However, up to now no kind of obligate plant ant has arrived. On the other hand, ant species loosely associated with particular plant species have already established themselves on the Krakataus. Docters van Leeuwen (1936) mentioned that the plant-ant Philidris myrmecodiae (referred to as Iridomyrmex myrmecodiae) had been found on the Krakataus in 1931 prior to the arrival of the ant plant Myrmecophila sinuosa (Polypodiaceae). Although Dammerman (1948) did not record Philidris ants before 1933, Docters van Leeuwen clearly stated that the ants had been seen in earlier periods. He also mentioned that Iridomyrmex myrmecodiae and Crematogaster baduvi are often associated with the epiphytic orchid Acriopsis liliifolia var. liliifolia (Koenig) (as Acriopsis javanica) in Java and that their relationships are not obligate (Docters van Leeuwen, 1929). Also in my experience most Philidris species tend to live in various kinds of ant plant or epiphyte but can live independently of them. However, with these ant plants present the survival of Philidris species has become more likely. The generalist ant plant Macaranga tanarius was commonly observed during on Rakata and Anak Krakatau (Pl. 5, F & G). Two ant species, Philidris myrmecodiae and Crematogaster ferrarii, frequently visited extrafloral nectaries of small trees of this species. This plant was first collected in 1896 on Panjang (Lang), later in 1905 on Rakata; it was very common on three islands and found mainly in Casuarina forests (Docters van Leeuwen, 1936; Tagawa et al., 1986). Another species with extrafloral nectaries was Hibiscus tiliaceus (Pl. 6, A C). In this plant was common along the coastline of every island. More ant species were observed being attracted to this plant than to Macaranga tanarius (Table 3). This plant was first found in 1896 on Panjang, and has thereafter been commonly seen on every island (Docters van Leeuwen, 1936; Tagawa, et al., 1986). Tukirin et al. (1993) recorded drift seeds of this species on the beach of Anak Krakatau, strongly suggesting that this plant is dispersed by sea currents. The common occurrence of generalist ant plants should have facilitated the establishment of some ant species during early succession on each island. Nesting sites Some ants use very specific sites for nesting, while others are generalists in this regard. In I tried to find as many ant colonies as possible to reveal the principal nesting site for each species. Around 160 nests were located for 49 species, which were sorted into five groups based on nesting behaviour,

36 36 Table 3. Ant species attracted to Hibiscus and Macaranga extrafloral nectaries ( ) Plant name Ant name Subfamily Location Remarks Hibiscus Philidris myrmecodiae Dolichoderinae Rakata beach Technomyrmex horni Dolichoderinae Anak Krakatau beach Anoplolepis gracilipes Formicinae Anak Krakatau Tramp spcies Camponotus (Tanaemyrmex) sp. 48 of SKY Formicinae Anak Krakatau beach Camponotus (Tanaemyrmex) sp. 153 of SKY Formicinae Sertung beach forest Shelter constructed Camponotus (Myrmamblys) bedoti Formicinae Sertung Camponotus (Colobopsis) sp. 38 of SKY Formicinae Anak Krakatau beach Oecophylla smaragdina Formicinae Anak Krakatau beach Paratrechina longicornis Formicinae Anak Krakatau Tramp species Polyrhachis (Cyrtomyrma) cf. lepida Formicinae Rakata Dealated queen Crematogaster (subgen. indet.) baduvi Myrmicinae Rakata Tetramorium bicarinatum Myrmicinae Anak Krakatau Tramp species Macaranga Philidris myrmecodiae Dolichoderinae Anak Krakatau Shelter constructed Crematogaster ferrarii Myrmicinae Anak Krakatau namely, species nesting in dead wood (often decayed), living trees (in decayed part or under bark), dead twigs (on trees or ground) and soil (including ground surface like leaf litter), and on tree leaves (or in a cluster of leaves). Many species nest in both dead wood and dead twigs. Nests were often located in soil under logs lying on the ground. In this case nests were often stretched into both wood and soil. Their nesting type was determined by which of the sites they tended to nest in. All seven species found from abandoned termite nests (mainly of Nasutitermes matangensis) that were globular and very strong (Pl. 5, A & B) were also collected from rotting wood. An abandoned nest of this termite often harboured more than two ant species. Among 49 species for which the nesting type was determined ca. 60% were dead-wood nesters (Fig. 8). Soil or leaf litter specialists were much fewer (14%). Species nesting on tree foliage were still fewer (2%). However, if more species are included for analysis using nest-site data obtained in other parts of Sundaland, the pattern slightly changes, with a larger proportion of the species nesting in soil (or leaf litter) and on tree leaves (Fig. 8). Most remarkable on the Krakataus was the almost complete lack of the species constructing carton nests on plant leaves. In other parts of Sundaland we can see such species, which are taxonomically widely distributed. Among them are species of the Technomyrmex strenuus group (Bolton, 2007), Dolichoderus taprobanae and related species, species of the Myrmicaria arachnoides group (Bakhtiar and Yamane, 2006; Bakhtiar et al., 2009), species of the Polyrhachis subgenera Myrmothrinax and Myrmatopa (Robson and Kohout, 2005; Noon-anant et al., 2009), species of the Camponotus subgenus Karavaievia (Dumpert, et al., 1995), and a Monomorium species (Yamane, personal observation). It seems unlikely that the absence of any of these species is due to an obligate relationship with particular Number of nests (%) Dead wood Living tree Dead twig Soil/surface Leaves Nesting sites Fig. 8. Nesting sites of Krakatau ants. Black bars indicates those in the 49 species for which records on the Krakatus are available. Gray bars include additional species with nest-site information from other parts of Sundaland. plant species that were absent on the Krakataus; their dispersal methods might be more important factors. Dispersal methods Ant colonies generally produce winged new queens and males for reproduction when they grow mature. These mate with ants of the opposite sex derived from other colonies, thus avoiding inbreeding. After mating inseminated new queens may fly some distance, finding appropriate sites for nesting. During this process there is a chance they will be caught in strong winds or air currents and transported to remote places. For most Krakatau ants Dammerman (1948, p. 245) favoured this dispersal mechanism to dispersal by sea currents, taking the absence of ant species with apterous queens as an indirect evidence (for most animal groups he considered dispersal on driftwood the main route; p. 263). Most of the Krakatau ants may have been able to cross the sea by air regardless of their nesting sites. In particular

37 A review of the ant fauna of the Krakatau Islands, Indonesia 37 the species nesting in soil would have had the least chance of traveling on the sea with adequate masses of soil. Thornton et al. (1988) sampled air-borne arthropods on Anak Krakatau using white water traps. Twenty-two ants were captured, most of which were winged ants (queens and males were not distinguished). They mentioned that all appear to represent species resident on the island, although this does not preclude an over-sea landfall. In 1939 Dammerman found a completely desiccated winged ant on ash covering the ground of Anak Krakatau (Dammerman, 1948, p. 61). In 1982 I also collected a winged queen of Oecophylla smaragdina near the summit of Anak Krakatau far from any vegetation. This species nests on trees weaving leaves with larval silk; the nest is not physically strong and is unlikely to be able to endure drifting on the sea. The tramp Anoplolepis gracilipes may also cross the water by air (for colony reproduction of this species, see Abbott, 2006). Species nesting in decayed wood and living tree trunks can cross the sea either by air or rafting. I do not have any direct evidence for the immigration of ants by rafting. I found some nests of Nylanderia bourbonica and Monomorium floricola (Pl. 6, D) from washed-up logs by the waterside on Panjang and Sertung in , though I could not determine whether these logs had contained the nests before arriving there. According to my data on nesting sites the proportion of wood-nesting species was highest, while those of the ground-surface nesters and tree-leaf nesters were lowest (Fig. 8). In particular I have not yet found any species constructing carton nests on plant leaves; it is most unlikely that their nests cross the sea by rafting (see under Nesting sites ). All this indicates the relative importance of rafting as a dispersal method for the Krakatau ants. In the case of termites the rafting is much more plausible. Abe (1984) and Yamane et al. (1992) reported that the termite fauna of the Krakataus was characterized by the dominance of lower termites that construct nests in wood. He found no soilnesting species in He concluded that the dispersal by rafting is more likely to have occurred in termites. Gathorne- Hardy et al. (2000) also did not find any soil nester in He supported Abe s hypothesis, but predicted the eventual arrival of soil nesters by air. Syaukani (2008) collected first soil-nesting species, Ancistrotermes spp., from Panjang in , but did not specify their dispersal route. However, all the others (18) are species nesting in wood or on trees, indicating the difficulty for soil-nesters in crossing the sea. In termites dispersal by air seems quite difficult because both a new queen and king together should cross a long distance before mating to initiate a colony. Using driftwood by inhabitant colonies may be the easiest way to cross the sea. Here I would like to emphasise the role of Nasutitermes matangensis in providing ants with nesting sites. This termite species constructs physically strong nests on tree trunks and branches that can be transported on drifting trees across the sea. Actually N. matangensis was found even in 1908, and has been a dominant species throughout the five survey periods (Dammerman, 1948; Syaukani, 2008). Syaukani found it on all four islands in I dissected abandoned old nests and frequently found ant colonies in them (Pl., 5 B). I think even live colonies of this species can harbour ant nests in small cavities within their nests. Ants would have had chances to travel in the nest of this termite to the Krakataus and also between the four islands of Krakatau (see also under Nesting sites ). In some ant groups in Asia, e.g., army ants (Aenictinae and Dorylinae) and Leptogenys and Diacamma (Ponerinae), the queens (or ergatoids and gamergates) cannot fly (wings are absent), and colonies multiply by fission (dependent colony foundation, or DCF, of Peeters and Molet, 2010; see also Peeters and Ito, 2000, for terminology) with new queen(s) and workers walking on the ground (Abe et al., 2012). In this case the rafting is also unlikely because the chances of a group of ants successfully crossing a long distance of water are very small. However, we know many cases in which isolated oceanic islands actually have species of these ant groups. For example, one species of Dorylus, four species of Aenictus and more than ten species of Leptogenys are known from Sulawesi (e.g., Jaitrong and Yamane, 2011; Yamane, personal observation), which is said to have never been connected with other land masses since settling in its present location. This indicates that there have been chances for ancestral stocks of these species to cross the sea in a long-time scale (Abe et al., 2012). The discovery of a Leptogenys species on the Krakataus shows that DCF ants did cross the sea, and this gives a clue for estimating the minimal time needed for DCF ants to arrive on islands that are located tens of kilometers from adjacent lands (Abe et al., 2012). In this connection it is interesting that species of the Leptogenys peuqueti group are unique in having gamergates rather than ergatoid queens that are common in other groups of Leptogenys (Ito, 1997). This system, thought to be adaptive in unpredictable and disturbed habitats, might have facilitated L. cf. peuqueti colonisation of the Krakataus (F. Ito, pers. comm.). No species of Dorylus and Aenictus were found on the Krakataus, and similarly Yamane (1983) did not record any species of swarm-founding bee (Apis and Trigona) except for the giant honeybee Apis dorsata that is famous for frequent long-distance migrations. Their absence may be because fission (budding) is a complicated process that does not allow even winged species like vespid wasps and apine bees to conduct long-distance travel (for swarm-founding in Vespidae, see Jeanne, 1991). In the case of ants, unlike in wasps and bees, colony reproduction by fission is generally, but not always, associated with an apterous queen. Although Dammerman (1948) gave special emphasis to the apterous queen, most important when discussing the difficulty of crossing water is not the winglessness of the queen but the complicated process of fission. Aenictus and Dorylus are not rare on both Java and Sumatra, and one species of Dorylus occurs even on Pulau

38 38 Sebesi (Dammerman, 1948; Yamane unpublished), located between the Krakataus and Sumatra and considered to be a stepping stone for immigration from Sumatra (but see Yukawa et al., 2000, and Thornton et al., 2002 for the minor role of Sebesi as a stepping stone). It would be most fascinating to witness the landing of one of these army ants onto Krakatau in the future. Some cultivated plants, weeds and animals (rats, cockroaches etc.) are suspected to have arrived in the Krakataus through human activity (Thornton, 1996). Some of them disappeared sooner or later (Docters van Leeuwen, 1936; Thornton, 1996) through the competition with native species. No ant species is claimed to have been transported by fishermen or tourists, though for Dolichoderus thoracicus, Tapinoma melanocephalum, and some Monomorium and Tetramorium species this possibility is not completely precluded. The island group became independent as a nature reserve in Protection of the island s ecosytem has become stricter than in the past, but even now there exists almost no control over visitors, including tourists and researchers, for their luggage, research equipment or clothes. As is evident from the experience in the Galapagos Islands (Watkins et al., 2007), with the increase of visitors, even under a strict control, the number of alien species can rise rapidly. However, on the Krakataus, in most cases the naturally established species network may eliminate aliens as has been observed during earlier phases of recolonisation. ACKNOWLEDGMENTS I would like to thank Dr. John Fellowes (Kadoorie Farm, Hong Kong) for his invaluable comments on an earlier draft of the manuscript and correction of English, and for Dr. Edward O. Wilson (Harverd University) for fruitful discussion. Prof. Fuminori Ito (Kagawa University) gave me useful information about ponerine ants. The following biologists kindly helped me during the Krakatau expeditions: Prof. Emeritus Hideo Tagawa (Kagoshima University) (1982 expedition), Prof. Emeritus Junichi Yukawa (Kyushu University) (1982), Dr. Tukirin Partomihardjo (Herbarium Bogoriense, Indonesia) (1982, 2005), Dr. Rosichon Ubaidillah (2006), Dr. Syaukani (Siah Kuala University) (2005, 2006), Prof. Shuichi Ikudome (Kogoshima Women s Junior College) (2005, 2006), Dr. Katsuo Goukon (Tohoku Gakuin University) (2005), and all the other members of the Krakatau Expeditions in 1982 and The late Prof. Takuya Abe (Kyoto University) collected ants in 1982, and gave me valuable suggestions. Prof. Kazuo Ogata (Kyushu University) identified some ant species collected by Abe and Yamane in Dr. Katsuyuki Eguchi (Tokyo Metropolitan University) and Dr. Shingo Hosoishi (Kyushu University) identified some species of Pheidole and Crematogaster respectively. Prof. Keiichi Onoyama (Kyoto City) took care of the mounted ant specimens collected by Dr. T. Abe in 1982 for around 30 years in his collection. Dr. Steven Shattuck (CSIRO, Australia) and Dr. Shingo Hosoishi arranged for me the set of ant specimens from the Krakataus preserved in the Australian National Insect Colleciton (ANIC). Dr. Kyoichiro Ueda (the Kitakyushu Museum of Natural History and Human History, Japan) allowed me to use the wet material collected by Abe and preserved at his museum. Prof. Eizi Suzuki (Kagoshima University) identified some plant species. Discussion with Mr. Akhmad Rizali (Bogor) on the ant fauna of the Thousand Islands Archipelago was useful. This study was supported by the Grant-in-Aid for Overseas Scientific Research ( ) from the Ministry of Education, Science and Culture, Japanese Government, and the Toyota Foundation (1982) (Leader: Hideo Tagawa), and Grant-in-Aid Kiban B ( ) for (Leader: ). I am much indebted to Lembaga Ilum Pengetahuan Indonesia (LIPI) for research permit and friendly help during our surveys. The photographs of ant specimens were taken by Dr. Weeyawat Jaitrong (The Natural History Museum of the National Science Museum, Thailand). Last but not least I thank the editor of this journal and the anonimous reviewer for their valuable comments. REFERENCES Abbott, K.L Spatial dynamics of supercolonies of the invasive yellow crazy ant, Anoplolepis gracilipes, on Christmas Islands, Indian Ocean. Diversity and Distributions, 12: Abe T Colonization of the Krakatau Islands by termites (Insecta: Isoptera). Physiology and Ecology of Japan, 21: Abe, T., Yamane, Sk. and Onoyama, K Ants collected on the Krakatau Islands 100 years after the great eruptions. Biogeography, 14: Agosti, D., Moog, J. and Maschwitz, U Revision of the Oriental plant-ant genus Cladomyrma. American Museum Novitates, 3283: Bakhtiar, E.Y. and Yamane, Sk Nesting biology of a tropical myrmicine ant, Myrmicaria arachnoids (Formicidae), in West Java, Indonesia. Journal of Hymenoptera Research, 15: B a k h t i a r, E.Y., Ya m a n e, Sk. and Ma ryat i, M Morphological and Behavioral characters of the two species groups of the ant genus Myrmicaria (Insecta: Hymenoptera: Formicidae: Myrmicinae) from Southeast Asia. Species Diversity, 14: Bingham, C.T Hymenoptera, Vol. II. Ants and cuckoowasps. Blanford, W.T. (ed.) Fauna of British India Including Ceylon and Burma. Taylor and Francis, London. 506 pp., 1 pl. Blaimer, B.B A subgeneric revision of Crematogaster and discussion of regional species-groups (Hymenoptera:

39 A review of the ant fauna of the Krakatau Islands, Indonesia 39 Formicidae). Zootaxa, 3482: Bolton, B A New General Catalogue of the Ants of the World. Harvard University Press, Cambridge. Bolton, B The ant tribe Dacetini. Memoirs of the American Entomological Institute, 65 (1/2): 1028 pp. Bolton, B Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute, 71: 370 pp. Bolton, B Taxonomy of the dolichoderine ant genus Technomyrmex Mayr (Hymenoptera: Formicidae) based on the worker caste. Contributions of the American Entomological Institute, 35: Bolton, B AntCat. An online catalog of the ants of the World. Accessed 30 January Bush, M.B. and Whittaker, R.J Non-equilibration in island theory of Krakatau. Journal of Biogeography, 20: Dammerman, K.W The fauna of Krakatau, Verlaten Island and Sebesy. Treubia, 3: Dammerman, K.W Part III. Krakatau s new fauna. Krakatau, Fourth Pacific Congress: Krakatau, pp Damemrman, K. W The fauna of Krakatau Verhandel. Kon. Ned. Akad. Wet., Afdel. Nat. II, 44: Diamond, J.M Avifaunal equilibria and species turnover rates on the Channel Islands of California. National Academy of Sciences Proceedings, 64: Docters van Leeuwen, W.M Kurze Mitteilang uber Ameisen Epiphyten aus Java. Bre. D. deutsch. Bot. Geselsch., 46: 90. (Indirect citation from Docters van Leeuwen, 1936) Docters van Leeuwen, W.M Krakatau A. Botany. Annales du Jardin Botanique de Buitenzorg, 46/47: Donisthorpe, H On the identity of Smith s types of Formicidae (Hymenoptera) collected by Alfred Russel Wallace in the Malay Archipelago, with descriptions of two new species. Annals and Magazines of Natural History, (10) 59: Eguchi, K A revision of the Bornean species of the ant genus Pheidole (Insecta: Hymenoptera: Formicidae: Myrmicinae). Tropics Monograph Series, 2: Emery, C Hymenoptera, fam. Formicidae, subfam. Formicinae. In: Wytsman, P., Genera Insectorum, 302 pp., 4 pls. Dumpert, K., Maschwitz, U., Weisflog, A., Rosciszewski, K. and Azarae, I.Hj. 1995, Six new weaver ant species from Malaysia: Camponotus (Karavaievia) striatipes, C. (K.) melanus, C. (K.) nigripes, C. (K.) belumensis, C. (K.) gentingensis, and C. (K.) micragyne. Malaysian Journal of Science, 16A: Fernández, F The American species of the Myrmicine ant genus Carebara Westwood (Hymenoptera: Formicidae). Caldasia, 26: Forel, A Ameisen aus Java und Krakatau. Beobachtet und Gesammelt. Notes from Leyden Museum, 31: , pls. 7 & 8. Gathorne-Hardy, F.J., Jones, D.T. and Mawdsley, N.A The recolonization of the Krakatau Islands by termites (Isoptera), and their biogeographical origins. Biological Journal of the Linnean Society, 71: Gorman, M Island Ecology. 79 pp. Chapman and Hall, London. Goukon, K Survey on the wasp fauna of the Krakatu Islands and its colonization process (in Japanese). In: Yamane, Sk. (ed.) A Study on the Colonization Process of aculeate Hymenoptera on the Krakatau Islands, pp (Not a publication; report to Japan Society for Promotion of Science) Heterick, B.E. and Shattuck, S Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae). Zootaxa, 2845: Hosoishi, S A taxonomic revision of the Asian endemic subgenus Physocrema of the genus Crematogaster (Hymenoptera: Formicidae). Zootaxa, 2062: Ikudome, S Bees of the Krakataus and adjacent areas (In Japanese). In: Yamane, Sk. (ed.) A Study on the Colonization Process of aculeate Hymenoptera on the Krakatau Islands, pp (Not a publication; report to Japan Society for Promotion of Science) Ito, F Colony characteristics and morphological caste differentiation in the ponerine ant genus Leptogenys in oriental tropics. Ethology, Ecology and Evolution, 8: Ito, F., Yamane, Sk., Eguchi, K., Woro, A.N., Sih, K., Tusji, K., Ohkawara, K., Yamauchi, K., Nishida, T. and Nakamura, K Ant species diversity in the Bogor Botanic Garden, West Java, Indonesia, with descriptions of two new species of the genus Leptanilla (Hymenoptera, Formicidae). Tropics, 10: Iwamoto, T Mammals, reptiles and crabs on the Krakatau Islands: their roles in the ecosystem. Ecological Research, 1: Jacobson, E.R De nieuwe fauna van Krakatau. Jaarverslag van den Topographischen Dienst in Nederlandsch-Indie, 4 (1908): (Indirect citation from Dammerman, 1948.) Jaitrong, W. and Yamane, Sk Synopsis of Aenictus species groups and revision of the A. curax and A. laeviceps groups in the eastern Oriental, Indo-Australian, and Australasian regions (Hymenoptera: Formicidae: Aenictinae). Zootaxa, 3128: Jeanne, R. L The swarm-founding Polistinae. In: Ross, K.G. and Matthews, R.W. (eds.), The Social Biology of Wasps, pp Comstock Publishing Associates,

40 40 Ithaca and London. Kohout, R.J New synonyms and nomenclatural changes in the ant genus Polyrhachis Fr. Smith (Hymenoptera: Formicidae: Formicinae). Memoirs of the Queensland Museum, 42: Kohout, R.J Review of Polyrhachis (Cyrtomyrma) Forel (Hymenoptera: formicidae: Formicinae) of Australia, Borneo, New Guinea and the Solomon Islands with descriptions of new species. Memoirs of the Queensland Museum, 52: LaPolla, J. S Acropyga (Hymenoptera: Formicidae) of the World. Contributions of the American Entomological Institute, 33(3): LaPolla, J. S., Brady, S.G. and Shattuck, S.O Phylogeny and taxonomy of the Prenolepis genus-group of ants (Hymenoptera: Formicidae). Systematic Entomology, 35: MacArthur, R.H. and Wilson, E.O An equilibrium theory of insular zoogeography. Evolution, 17: MacArthur, R.H. and Wilson, E.O The theory of Island Biogeography. Princeton University Press, Princeton. 203 pp. McGlynn, T.P The worldwide transfer of ants: geographical distribution and ecological invasions. Journal of Biogeography, 26: Noon-anant, N., Kohout, R., Watanasit, S., Yamane, Sk. and Wiwatwitaya, D Additional records of Polyrhachis (Myrmatopa) varicolor Vi e h m e y e r (Formicidae: Formicinae) from southern Thailand, with notes on its nesting habits. Natural History Journal of Chulalongkorn University, 9: Ogata, K., Abe, J., Matsui, S. and Simbolon, H Ants of Indonesia with special reference to taxonomic diversity in local communities and phylogenetic relations of populations in Oecophylla smaragdina. In: Yukawa, J. (ed.) Studies of the diversity and geographical ecology of insects on islands in Indonesia. (Report to JSPS: , not a publication) (In Japanese) Peeters, C. and Ito, F Colony dispersal and the evolution of queen morphology in the social Hymenoptera. Annual Review of Entomology, 46: Peeters, C. and Molet, M Colony reproduction and life histories. In: Lach, L., Parr, C.L. and Abbott, K.L. (eds.), Ant Ecology, Oxford University Press, Oxford, pp Pfeiffer, M., Mezger, D., Hosoishi, S., Bakhtiar, E.Y. and Kohout, R The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology, 4: Quek, S.-P., Davies, S.J., Ashton, P.S., Itino, T. and Pierce, N The geography of diversification in mutualistic ants: a gene s-eye view into the Neogene history of Sundaland rain forest. Molecular Ecology, 16: Rigato, F. and Bolton, B The ant genus Liomyrmex: a review (Hymenoptera Formicidae). Bollettino della Società Entomologica Italiana, 133: Rizali, A., Lohman, D.J., Damayanti, B., Lilik, B.P., Hermanu, W., Bos, M.M., Yamane, Sk. and Schulze, C.H Ant communities on small tropical islands: effects of island size and isolation are obscured by habitat disturbance and tramp ant species. Journal of Biogeography, 37: Robson, S.K.A. and Kohout, R Evolution of nest-weaving behaviour in arboreal nesting ants of the genus Polyrhachis Fr. Smith (Hymenoptera: Formicidae). Australian Journal of Entomology, 44: Russell, J.A., Moreau, C.S., Goldman-Huertas, Fujiwara, M., Lohman, D.L. and Pierce, N.E Bacterial gut symbionts are tightly linked with evolution of herbivory ants. Proceedings of the National Academy of Science, USA, 106: Schlick-Steiner, B.C., Steiner, F.M. and Moder, K Tetramorium pacificum Mayr, 1870, T. scabrum Mayr, 1879 sp. rev., T. manobo (Calilung, 2000) (Hymenoptera: Formicidae) three good species. Myrmecologische Nachrichten, 8: Schultz, T. R. and McGlynn, T. P The interactions of ants with other organisms. In: Agosti, D., Majer, J. D., Alonso, L. E. and Schultz, T. R. (eds.), Ants: Standard methods for measuring and monitoring biodiversity, pp Smithsonian Institution Press, Washington and London. Seifert, B The ant genus Cardiocondyla (Insecta: Hymenoptera: Formicidae) a taxonomic revision of the C. elegans, C. bulgarica, C. batesii, C. nuda, C. shuckardi, C. stambuloffii, C. wroughtonii, C. emeryi, and C. minutior species groups. Annalen des Naturhistorischen Museums in Wien, 104B: Shattuck, Generic revision of the ant subfamily Dolichoderinae (Hymenoptera: Formicidae). Sociobiology, 21: Simkin, T. and Fiske, R.S Krakatau 1883: The Volcanic Eruption and Its Effect. Smithsonian Institution Press, Washington, D.C. 464 pp. Suzuki, E., Tukirin, P. and Edi, T A ten-year succession of Saccharum spontaneum and Casuarina equisetifolia vegetations on Anak Krakatau, Indonesia. Tropics, 4: Syaukani Termites of the Krakataus and adjacent islands ( ). In: Yamane, Sk. (ed.) A Study on the Colonization Process of aculeate Hymenoptera on the Krakatau Islands, pp (Not a publication; report to Japan Society for Promotion of Science) Tagawa, H., Suzuki, E., Tukirin, P. and Adismarto, S Vegetation and succession on the Krakatau Islands, Indonesia. Vegetatio, 60:

41 A review of the ant fauna of the Krakatau Islands, Indonesia 41 Tagawa, H., Suzuki, E. and Tukirin, P A list of plant species collected from the Krakatau Islands and adjacent Areas, Indonesia. Memoirs of the Kagoshima University Cemter for South Pacific, 7: Taylor, R. W Rhoptromyrmex rawlinsoni sp. nov., a new apparently workerless parasitic ant from Anak Krakatau, Indonesia (Hymenoptera: Formicidae: Myrmicinae). Memoirs of the Museum of Victoria, 53: Thornton, I.W.B K. W. Dammerman Fore runner of island equilibrium theory? Global Ecology and Biogeography Letters, 2: Thornton, I.W.B Krakatau. The Destruction and Reassembly of an Island Ecosystem. Harvard University Press, Cambridge, Massachusetts, and London, England. 346 pp. Thornton, I.W.B., New, T.R., McLaren, D.A., Sudarman, H.K. and Vaughan, P.J Air-borne arthropod fall-out on Anak Krakatau and a possible pre-vegetation pioneer community. Philosophical Transactions of the Royal Society of London B, 322: Thornton, I.W.B., Runciman, D., Cook, S., Lumsden, L.F., Tukirin, P., Schedvin, N.K., Yukawa, J. and Ward, S.A How important were stepping stones in the colonization of Krakataus. Biological Journal of the Linnean Society, 77: Tukirin, P., Edi, M. and Soedarsono, R Drift fruits and seeds on Anak Krakatau Beaches, Indonesia. Tropics, 2: Wa r a, A., Ro s i c h o n, U. and Ya m a n e, Sk Ant (Hymenoptera: Formicidae) of the Krakataus, and Sebesi and Sebuku Islands. Treubia, 36: 1 9. Ward, P. S Taxonomy, phylogeny and biogeography of the ant genus Tetraponera (Hymenoptera: Formicidea) in the Oriental and Australian region. Invertebrate Taxonomy, 15: Watkins, G., Cardenas, S. and Tapia, W Introduction. Galapagos Report : Wheeler, W. M The ants of Borneo. Bulletin of the Museum of Comparative Zoology at Harvard College, 63: Wheeler, W. M Ants of Krakatau and other islands in the Sunda Strait. Treubia, 5: Wheeler, W. M Additions to the ant-fauna of Krakatau and Verlaten Islands. Treubia, 16: Whittacker, R.J Dynamic hypotheses of richness on islands and continents. In: Lomolino, M.V. and Heaney, L.R. (eds.) Frontiers of Biogeography. New Directions in the Geography of Nature. Pp Sinauer Associates, Inc. Publishers, Sunderland, Massachusetts. Whittacker, R.J., Bush, M.B. and Richards, K Plant recolonization and vegetation succession on the Krakatau Islands. Ecological Mongraphs, 59: Whittacker, R.J., Bush, M.B., Tukirin, P., Asquith, N.M. and Richards, K Ecological aspects of plant colonization of the Krakatau Island. GeoJournal, 28: Wilson, E.O The species equilibrium. In: Woodwell, G.M. and Smith, H.H. (eds.), Diversity and Stability in Ecological Systems. Brookhaven Symposium in Biology, 22, pp Brookhaven National Laboratory, Upton, New York. Wilson, E.O. and Taylor, R.W The ants of Polynesia (Hymenoptera: Formicidae). Pacific Insects Monograph, 14: Winchester, S Krakatoa: The Day the World Exploded: August 27, HarperCollins Publishers, New York. 416 pp. Yamane, Sk The aculeate fauna of the Krakatau Islands (Insecta, Hymenoptera). Reports of the Faculty of Science, Kagoshima University (Earth Sciences and Biology), 16: Yamane, Sk Krakatau in 1982, and the commencement of myrmecological research. Nature and Insects, 40(1): (In Japanese.) Yamane, Sk Ants of the Krakataus and adjacent areas (Hymenoptera, Formicidae). In: Yamane, Sk. (ed.) A Study on the Colonization Process of aculeate Hymenoptera on the Krakatau Islands, pp (Not a publication; report to Japan Society for Promotion of Science) Yamane, Sk Odontoponera denticulata (F. Smith) (Formicidae: Ponerinae), a distinct species inhabiting disturbed areas. Ari [Journal of the Myrmecological Society of Japan], 32: 1 8. Yamane, Sk., Abe, T. and Yukawa, J Recolonization of the Krakataus by Hymenoptera and Isoptera (Insecta). GeoJournal, 28: Yukawa, J Recolonization of the Krakatau Islands by insects [1]. Insectarium, 26 (1): (In Japanese.) Yukawa, J., Tukirin, P., Yata, O. and Hirowatari, T An assessment of the role of Sebesi Island as a stepping-stone for the colonization of the Krakatau Islands by butterflies. Esakia, 40: 1 10

42 42 Explanations of plates Plate 1 A. New lava protruding to sea, with poor vegetation, Anak Krakatau, 20 Aug. 2005; B. Bare slope of Anak Krakatau, 10 July 1982; C. Young Casuarina forest on Anak Krakatau, 20 Aug. 2005; D. Casuarina forest on Anak Krakatau, 30 Dec. 2006; E. Rather developed coastal forest, Anak Krakatau, 31 Dec Plate 2 A. Anak Krakatau (left) and Rakata (right) seen from Sertung, 16 Aug. 2006; B. Anak Krakatau (left), Rakata (centre) and Panjang (right), 1 Jan. 2007; C. Coastal forest, Panjang, 28 Dec Plate 3 A. Large trees with buttress roots, Rakata, 31 Dec. 2006; B. Well-developed forest of Rakata, 19 Aug Plate 4 A. PHPA ship used in our survey and a small boat for landing, Rakata, 19 Aug. 2005; B. Fisherman s boat on the coast of Sertung, 27 Dec. 2006; C. Dr. Syaukani picking up termites from thrown-up drift wood, Sertung, 27 Dec. 2006; D. Seedling of coconut palm, Panjang, 18 Aug. 2005; E. Very young Casuarina forest along the coast of Sertung, 27 Dec Plate 5 A. Nasutitermes matangensis nest on a tree stem, Rakata, 19 Aug. 2005; B. Abandoned N. matangensis nest, Rakata, 19 Aug (part of envelope removed to show inside); C. Anoplolepis gracilipes attending scale insects, Rakata, 31 Dec. 2006; D. Anoplolepis gracilipes on flowers of unknown plant, Sertung, 30 Dec., 2006: E. Workers of Camponotus (Tanaemyrmex) sp. 153 of SKY on flowers of Morinda citrifolia, Sertung, 2 Jan. 2007; F. Generalist ant plant, Macaranga tanarius, Anak Krakatau, 30 Dec. 2006; G. Crematogaster (Crematogaster) ferrarii worker attracted to extrafloral nectary of Macaranga tanarius, Anak Krakatau, 30 Dec Plate 6 A. Underside of leaf of Hibiscus tiliaceus (extrafloral nectaries, EFNs, protected with pulp cover by Camponotus (Tanaemyrmex) sp. 153 of SKY); B. Workers of the same ant species attending EFNs of Hibiscus; C. EFNs on the underside of leaf of Hibiscus (A C, Sertung, 2 Jan. 2007); D. Monomorium floricola workers attracted to powdered-cheese bait on landed-up wood, Panjang, 28 Dec. 2006; E. Oecophylla smaragdina workers carrying a caterpillar on tree trunk, Rakata, 30 Dec Plate 7 DOLICHODERINAE. A, B. Chronoxenus wroughtonii javanus; C, D. Dolichoderus thoracicus-complex; E, F. Iridomyrmex anceps; G, H. Ochetellus sp. 1 of SKY; I, J. Philidris myrmecodiae; K, L. Tapinoma sp. 7 of SKY; M, N. Technomyrmex albipes. Plate 8 DOLICHODERINAE. A, B. Technomyrmex difficilis; C, D. T. horni. FORMICINAE. E, F. Acropyga acutiventris; G, H. Anoplolepis gracilipes; I, J. Nylanderia bourbonica; K, L. Nylanderia sp. 5 of SKY; M, N. Paraparatrechina cf. opaca. Plate 9 FORMICINAE. A, B. Paraparatrechina sp. 8 of SKY; C, D. Pseudolasius minutus; E, F. Oecophylla smaragdina; G, H. Camponotus (Colobopsis) leonardi-complex (major); I, J. C. (Colobopsis) sp. 9 of SKY (major); K, L. ditto (minor). Plate 10 FORMICINAE. A, B. Camponotus (Colobopsis) sp. 38 of SKY (major); C, D. C. (Colobopsis) sp. 128 of SKY (major); E, F. Camponotus (Myrmamblys) bedoti (major); G, H. ditto (minor) from P. Sebesi; I, J. C. (Myrmamblys) sp. 101 (major); K, L. Camponotus (Tanaemyrmex) arrogans (minor) from P. Sebesi. Plate 11 FORMICINAE. A, B. Camponotus (Tanaemyrmex) sp. 48 of SKY (major); C, D. ditto (minor); E, F. C. (Tanaemyrmex) sp. 72 of SKY (major); G, H. C. (Tanaemyrmex) sp. 153 of SKY (major); I, J. ditto (minor).

43 A review of the ant fauna of the Krakatau Islands, Indonesia 43 Plate 12 FORMICINAE. A, B. Camponotus (Tanaemyrmex) sp. 154 of SKY; C, D. ditto (monor); E, F. Echinopla lineata; G, H. Polyrhachis (Chariomyrma) arcuata; I, J. Polyrhachis (Cyrtomyrma) cf. lepida (queen). Plate 13 FORMICINAE. A, B. Polyrhachis (Myrma) illaudata; C, D. P. (Myrma) proxima; E, F. Polyrhachis (Myrmhopla) abdominalis; G, H. P. (Myrmhopla) bicolor; K, L. P. (Myrmhopla) caligata; I, J. P. (Myrmhopla) dives. Plate 14 FORMICINAE. A, B. Polyrhachis (Myrmhopla) flavoflagellata. PSEUDOMYRMICINAE. C, D. Tetraponera allaborans; E, F. T. nitida; G, H. T. rufonigra. CERAPACHYINAE. I, J. Cerapachys sp. 64 of SKY. Plate 15 AMBLYOPONINAE. A, B. Prionopelta kraepelini. PONERINAE. C, D. Anochetus graeffei; E, F. Cryptopone sp. 11 of SKY; G, H. Hypoponera confinis javana; I, J. H. sp. B; K, L. H. sp. A; M, N. H. sp. C. Plate 16 PONERINAE. A, B. Hypoponera sp. D; C, D. H. sp. E; E, F. H. sp. F; G, H. Leptogenys cf. peuqueti; I, J. Myopias breviloba; K, L. M. sp. 11 of SKY; M, N. Odontomachus simillimus. Plate 17 PONERINAE. A, B. Odontoponera denticulata; C, D. Pachycondyla (Brachyponera) cf. sp. 28 of SKY; E, F. Ponera sp. A; G, H. P. sp. B; I, J. Platythyrea parallela. MYRMICINAE. K, L. Pyramica dohertyi; M, N. P. karawajewi (queen). Plate 18 MYRMICINAE. A, B. Strumigenys emmae; C, D. S. godeffroyi; E, F. Lordomyrma sp. 3 of SKY; G, H. Vollenhovia sp. 70 of SKY; I, J. Monomorium destructor; K, L. M. floricola; M, N. M. cf. monomorium. Plate 19 MYRMICINAE. A, B. Monomorium sp. 1 of SKY; C, D. Oligomyrmex sp. 33 of SKY (major); E, F. ditto (minor); G, H. Solenopsis sp. 1 of SKY; I, J. Rhoptromyrmex rawlinsoni; K, L. Tetramorium bicarinatum; M, N. T. cf. insolens. Plate 20 MYRMICINAE. A, B. Tetramorium lanuginosum; C, D. T. simillimum; E, F. T. pacificum; G, H. Pheidole dammermani (major); I, J. ditto (minor); K, L. P. miseranda (major); M, N. ditto (minor). Plate 21 MYRMICINAE. A, B. Pheidole cf. oceanica (major); C, D. ditto (minor); E, F. P. plagiaria (major) from P. Sebesi; G, H. ditto (minor); I, J. P. sauberi (major); K, L. ditto (minor); M, N. P. nodgii verlatensis (major); O, P. ditto (minor). Plate 22 MYRMICINAE. A, B. Crematogster (Crematogaster) ferrarii; C, D. C. (C.) jacobsoni; E, F. C. (C.) sp. 39 of SKY; G, H. Crematogaster (C.) cf. sp. 77 of SKY; I, J. Crematogaster (C.) sewardi; K, L. Crematogaster (Orthocrema) baduvi; M, N. Liomyrmex gestroi. Plate 23 MYRMICINAE. A, B. Cardiocondyla cf. kagutsuchi; C, D. C. tibodana; E, F. C. wroughtonii; G, H. C. sp. 5 of SKY; I, J. Myrmecina sp. A; K, L. Pristomymrmex brevispinosus.

44 44 Plate 1

45 A review of the ant fauna of the Krakatau Islands, Indonesia 45 Plate 2

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47 A review of the ant fauna of the Krakatau Islands, Indonesia 47 Plate 4

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53 A review of the ant fauna of the Krakatau Islands, Indonesia 53 Plate 10

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55 A review of the ant fauna of the Krakatau Islands, Indonesia 55 Plate 12

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57 A review of the ant fauna of the Krakatau Islands, Indonesia 57 Plate 14

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59 A review of the ant fauna of the Krakatau Islands, Indonesia 59 Plate 16

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61 A review of the ant fauna of the Krakatau Islands, Indonesia 61 Plate 18

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66 66 Plate 23