Crematogaster (Physocrema) sewardi Forel

Hosoishi, Shingo & Ogata, Kazuo, 2009, A taxonomic revision of the Asian endemic subgenus Physocrema of the genus Crematogaster (Hymenoptera: Formicidae), Zootaxa 2062, pp. 15-36 : 28-29

Crematogaster (Physocrema) sewardi Forel

( Figs 9 , 17 , 29 )

Crematogaster deformis r. sewardi Forel, 1901: 64 . LECTOTYPE worker (top specimen of two on one pin) (by present designation) and one paralectotype worker and queen from MALAYSIA: Borneo (H. Seward) (MHNG) [examined]. Combination in C. ( Physocrema ) by Emery, 1922: 140. Raised to species by Hosoishi & Ogata 2008: 7.

Measurements and indices. HW 0.85–1.32; HL 0.77–1.22; CI 105–111; SL 0.70–0.96; SI 72–83; EL 0.16–0.24; PW 0.51–0.74; WL 0.96–1.40; PSL 0; PtL 0.28–0.42; PtW 0.21–0.36; PtH 0.15–0.22; PpL 0.19–0.28; PpW 0.23–0.34; PtHI 52–57; PtWI 74–86; PpWI 113–129; WI 94–116 (Three workers measured).

Description of worker. Workers with pronounced size polymorphism.

Scape not reaching posterior corner of head in large workers.

In lateral view, dorsal profile of promesonotum convex; propodeum distinctly raised relative to promesonotum. Anterior margin of pronotal collar slightly concave in dorsal view. Metanotal groove convex posteriorly in dorsal view in large workers, deep and situated posteriorly to the posterior ridge of pronotum in lateral view; thorax strongly constricted in middle in dorsal view. In dorsal view, some longitudinal rugulae connecting between mesonotum and propodeum; the boundary distinct. Propodeal spiracle situated away from the metapleural gland orifice, the distance between them much greater than the propodeal spiracle diameter. Propodeal spines absent.

Clypeus sculptured with longitudinal rugulae.

Standing pilosity sparse on dorsal face of head, abundant on promesonotum. Dorsal face of head with decumbent setae. Clypeus with short setae. Fourth abdominal tergite with appressed setae. Dorsal setae on fourth abdominal tergite directed posteriorly.

Body color black.

Distribution. Crematogaster (P.) sewardi is the most wide-ranging species of the subgenus Physocrema ( Fig. 29 ). This species ranges from Thailand to Malaysia (Peninsula and Borneo) and to Indonesia (Kalimantan, Sumatra, Krakatau Island, Java, Bali and Lombok).

Remarks. This species is very similar to C. (P.) ampullaris , but can be distinguished by the dorsal outline of the mesosoma and the depth of the metanotal groove.

The MHNG syntypes were lighter colored than normal, but otherwise match the characters of the specimens examined.

Among the Physocrema species, C. (P.) ampullaris , C. (P.) difformis , and C. (P.) sewardi are very similar to each other. Crematogaster (P.) sewardi is widely distributed in South East Asia, but almost all have been referred to as C. (P.) difformis in the past. It is also likely that C. (P.) sewardi has been misidentified as C. (P.) difformis in the literature ( Attygalle et al. 1989; Gay & Hensen, 1992; Ito et al. 2001; Jaitrong & Nabhitabhata, 2005; Jones et al. 2005). Based on the key above, C. (P.) difformis can be easily distinguished from ampullaris and sewardi , but as revealed above, the latter two species are very similar to each other and have been frequently confused. Crematogaster (P.) difformis and C. (P.) sewardi are geographically sympartric in the Malay Peninsula and Borneo, whereas C. (P.) ampullaris and C. (P.) sewardi are allopatric. Crematogaster (P.) ampullaris is found in Sulawesi, Timor and Philippines, and C. (P.) sewardi in Indochina, Malay Peninsula, Borneo, Sumatra, Krakatau Island, Java, Bali and Lombok. The slight morphological differences and allopatric distribution may imply that the two species are relatively new taxa.

Specimens examined. THAILAND: 6 workers, Sakaerat lowland forest (DEF), Nakornratchasima, 10. vii. 1999 (Sk. Yamane); 6 workers, Nam Tok Philio NP (300–500m alt.), Chanthaburi Prov., 22. xi. 2003 (Sk. Yamane); 4 workers, Khao Soi Dao, W. S., Chanthaburi Prov., 19. vii. 1997 (H. Okido); 4 workers, Khao Soi Dao, W. S., Chanthaburi Prov., 19. vii. 1997 (Sk. Yamane); 2 workers, Khao Chong (river side), Trang Prov., 24. viii. 1998 (Sk. Yamane) MALAYSIA: 11 workers, 7miles, Cameron Highland, 9. iii. 2005 (S. Hosoishi); 4 workers, 7miles, Cameron Highland, 12. iii. 2005 (S. Hosoishi); 3 workers, Poring, Kinabalu (HQ, 550m), Sabah, 17. iii. 1995 (Sk. Yamane); 2 workers, Kota Kinabalu, Sabah, 22. vii. 1996 (K. Eguchi). SINGAPORE: 3 workers, 4. xii. 1995 (Sk. Yamane); 2 workers, 23. vii. 1996 (Sk. Yamane); BRUNEI: 2 workers, Mixed Dipt. For., Dryobalanops beccarii, Site 7. 50m alt., Fog 11, Andalau, viii. 1991 (N. Mawdsley); INDONESIA: 3 workers, Kutai (Kal. Tim.), Kalimantan, 17. viii. 1986 (T. Yajima); 2 workers, Teluk Kabung nr Padang, Sumatra, 14. viii. 1985 (Sk. Yamane); 1 worker, Sako nr Tapan, Sumatra, 4–5. ix. 1985 (Sk. Yamane); 1 worker, Limau Manis nr Padang, Sumatra, 3. ix. 1985 (Sk. Yamane); 2 workers, P. Rakata Kecil, Krakatau Is., 31. vii. 1982 (Sk. Yamane); 2 workers, P. Peucang nr Ujung Kulon, 5. viii. 1982 (Sk. Yamane); 1 worker, P. Sertung, Krakatau Is., 30. vii. 1982 (Sk. Yamane); 1 worker, P. Sertung, Krakatau Is., 6. vii. 1982 (Sk. Yamane); 3 workers, Bogor, Java, 4–8. xi. 1985 (Sk. Yamane); 3 workers, 1 male, Pulau Rakata, Krakatau Is., Sunda Strait, 1. i. 2007 (RK07-SKY-04) (Sk. Yamane); 1 queen, Pulau Rakata, Krakatau Is., Sunda Strait, 1. i. 2007 (RK07-SKY-15) (Sk. Yamane); 1 worker, 1 queen, Pulau Sertung, Krakatau Is., Sunda Strait, 30. xii. 2006 (RK06-SKY-35) (Sk. Yamane); 2 workers, Pulau Sebesi, Lampung Prov., Sunda Strait, 12. viii. 2005 (Syaukani); 2 workers, P. Anak Krakatau, Krakatau Is., Sunda Strait, 17. viii. 2005 (Rk05-SKY-113) (Sk. Yamane); 2 workers, P. Anak Krakatau, Krakatau Is., Sunda Strait, 17. viii. 2005 (RK05-SKY-117) (Sk. Yamane); 3 workers, 1 male, Surisura, Pulau Siberut, Mentawai Is., 20. ii. 2007 (SU07-SKY-041) (Sk. Yamane); 2 workers, Carita, W. Java, 24. xii. 2006 (JV06-SKY-08) (Sk. Yamane); 2 workers, Bogor, Java, 9. xi. 1985 (Sk. Yamane); 1 worker, Campus of Gajah Mada Univ. (100m alt.), Yogyakarta, Java, 19. xii. 2002 (F. Yamane); 8 workers, Campus of Gajah Mada Univ. (100m alt.), Yogyakarta, Java, 29. xii. 2002 (F. Yamane); 6 workers, Dusun PK, Jelati Mendaya, Bali, 5–6. v. 1998 (Sk. Yamane); 20 workers, Senaru, Lombok, 30. ix. 2000 (H. Simbolon); 7 workers, Senaru, Lombok, 30. ix. 2000 (J. Abe); 4 workers, Senaru, Lombok, 30. ix. 2000 (K. Ogata); 2 workers, Kopi house nr Semaya, Lombok, 29. x. 1998 (K. Eguchi).

Figures

FIGURES 8 − 9. Setae on the fourth abdominal tergite: 8 — C. (P.) difformis; 9 — C. (P.) sewardi.

FIGURES 10 − 17. Physocrema species in lateral view. Scale bars are all 0.5 mm. 10 — C. (P.) ampullaris, [Sampulage (1000 m), nr Mangktana, S. Sulawesi]; 11 — C. (P.) aurita, [Maeklong Watershed Research Station, Kanchanaburi Prov.]; 12 — C. (P.) difformis, [Lambir N. P., Miri, Sarawak, Borneo]; 13 — C. (P.) inflata, [Ulu Gombak, Malay Peninsula]; 14 — C. (P.) mucronata, [Satar’s House, Ulu Gadut, nr Padang, Sumatra]; 15 — C. (P.) onusta, [Barito Ulu 150 m alt., Kalimantanm]; 16 — C. (P.) physothorax, [Universiti Kebangsaan Malaysia Forest, Malay Peninsula]; 17 — C. (P.) sewardi, [7 miles, Cameron Highland, Malay Peninsula].

FIGURES 27 – 32. Distribution of Physocrema species in Southeast Asia. 27 — C. (P.) onusta; 28 — C. (P.) physothorax; 29 — C. (P.) sewardi; 30 — C. (P.) tanakai; 31 — C. (P.) vacca; 32 — C. (P.) yamanei.