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

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Crematogaster (Physocrema) sewardi Forel


Crematogaster (Physocrema) sewardi Forel 

( Figs 9View FIGURES 8 − 9, 17View FIGURES 10 − 17, 29View FIGURES 27 – 32)

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. 29View FIGURES 27 – 32). 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).


Museum d'Histoire Naturelle














Crematogaster (Physocrema) sewardi Forel

Hosoishi, Shingo & Ogata, Kazuo 2009

Crematogaster deformis

Hosoishi 2008: 7
Emery 1922: 140
Forel 1901: 64