Crematogaster (Physocrema), Forel

Hosoishi, S. & Ogata, K., 2009, A taxonomic revision of the Asian endemic subgenus Physocrema of the genus Crematogaster (Hymenoptera: Formicidae)., Zootaxa 2062, pp. 15-36 : 17-19

The subgenus Physocrema Forel

Physocrema Forel, 1912: 220 [as subgenus of Crematogaster ]. Type-species: Crematogaster inflata , by subsequent designation of Wheeler 1913: 82.

Physocrema as genus: Soulie, 1964: 398.

Physocrema as junior synonym of Crematogaster : Brown, 1973: 183 [provisional]; Smith, D. R. 1979: 1376; Holldobler & Wilson, 1990: 13.

Physocrema as subgenus of Crematogaster : Forel, 1912: 220; Forel, 1917: 242; Emery, 1922: 139; Wheeler,W. M. 1922: 662; subsequent authors except those above; Bolton, 1995: 42.

Diagnosis of worker. Head subquadrate, slightly broader than long, with weakly concave posterior margin, angular posterior corners and subparallel sides. Occipital carinae developed. Mandible striate, with four teeth in small workers and five in larger workers, apical and subapical teeth large. Anterior margin of clypeus convex with slightly impressed median portion (Figs 1, 2); anterolateral margins of clypeus protruded anteriorly, resulting in an appearance of the anterolateral and anteromedian margins being at about the same level (Figs 1, 2); posterior margin of clypeus rounded between frontal lobes. Frontal carinae almost parallel. Antennae 11 segmented; antennal club 4-jointed. Compound eyes large but not distinctly projecting beyond lateral margins of head in full face view.

Pronotum and mesonotum usually without defined suture, rarely promesonotal suture present in large workers. Mesothoracic spiracle reduced to form small pit dorsoventrally. Variable extent of posterior mesosoma enlarged and swollen (Figs 3, 4). Metapleural gland opening circular; propodeal spiracle facing posterolaterally (Figs 3, 4).

Petiole flattened without node nor subpetiolar process; spiracle situated anteriorly midway between dorsal and ventral margins of petiole in lateral view, directed laterally; in dorsal view, elliptical with convex sides, longer than broad (Fig. 5). Postpetiole without distinctly longitudinal median sulcus, weakly bilobed behind in large workers (Fig. 5); spiracle situated distinctly anteriorly on the lateral surface.

Comments. Workers of the subgenus Physocrema can be distinguished from those of all other subgenera of Crematogaster by the features of (1) anteromedian margin of clypeus convex with slightly impressed median portion; (2) anterolateral margins of clypeus produced anteriorly; (3) 4-jointed antennal club (but, 3- jointed in mucronata ); (4) propodeum swollen; (5) metapleural gland orifice circular; (6) petiole elliptical; (7) petiole without node-like process posteriorly. The subgenus is unique among Asian Crematogaster ants in having features (4), (5), (6) and (7). The workers of the subgenus Physocrema share features (1), (2), (3) and (7) with the subgenus Paracrema . In Asian Crematogaster specimens examined, the workers of the subgenera Crematogaster , Decacrema , Mesocrema , Oxygyne , Paracrema , Physocrema and Xiphocrema share features (2) and (7).

Distribution. Southeast Asia: Vietnam (southern parts), Laos, Cambodia, Thailand, Myanmar (southeastern parts), Malaysia (Peninsula and Borneo), Singapore, Indonesia (Sumatra, Mentawai, Java, Bali, Lombok, Kalimantan, Sulawesi, Timor), Philippines (Fig. 21).

Synonymic list of the subgenus Physocrema Forel

ampullaris F. Smith, 1861 .

aurita Karavajew, 1935 .

bakeri Menozzi, 1925 .

difformis F. Smith, 1857 .

= edentata Mayr, 1867 .

inflata F. Smith, 1857 .

= moorei Donisthorpe, 1941 . syn. nov.

mucronata Emery, 1900 . stat. rev.

= fulmeki Forel, 1922 . syn. nov.

onusta Stitz, 1925 .

physothorax Emery, 1889 .

sewardi Forel, 1901 .

tanakai Hosoishi & Ogata , sp. nov.

vacca Forel, 1911 . stat. nov.

= stethogompha stethogompha Wheeler, W. M., 1919 . syn. nov.

= stethogompha detritinodis Wheeler, W. M., 1919 . syn. nov.

yamanei Hosoishi & Ogata , sp. nov.

Key to species based on the worker caste (except for C. bakeri , which is incertae sedis.)

1 Propodeal spines developed and with pointed apices................................................................................................... 2

- Propodeal spines undeveloped and forming obtuse lobes ............................................................................................ 4

2 Antennal club 3-jointed. Pronotum raised steeply toward mesonotum in lateral view................................ mucronata

- Antennal club 4-jointed. Pronotum raised moderately toward mesonotum in lateral view.........................................3

3 In lateral view, pronotum and mesonotum forming a single convexity, propodeum distinctly raised relative to promesonotum, metanotal groove deep......................................................................................................................... vacca

- In lateral view, pronotum and mesonotum forming a single convexity, propodeum slightly raised relative to promesonotum, metanotal groove less deep.................................................................................................. yamanei sp. nov.

4 Dorsal median portion of head swollen................................................................................................ tanakai sp. nov.

- Dorsal median portion of head not swollen..................................................................................................................5

5 Propodeal spiracle situated near the metapleural gland orifice, the distance between them about the same as the propodeal spiracle diameter (Fig. 4) ............................................................................................................................. 6

- Propodeal spiracle situated away from the metapleural gland orifice, the distance between them much greater than the propodeal spiracle diameter (Fig. 3) ....................................................................................................................... 9

6 Clypeus smooth and shining without longitudinal rugulae (Fig. 1)..................................................................... inflata

- Clypeus striated with rugulae (Fig. 2)..........................................................................................................................7

7 Dorsal face of head strongly striated with abundant longitudinal rugulae. Scape not reaching posterior corner of head in large workers. Workers with pronounced size polymorphism.......................................................................... aurita

- Dorsal face of head not strongly striated with longitudinal rugulae. Scape reaching posterior corner of head. Workers monomorphic in size..................................................................................................................................................... 8

8 The posterior portion of pronotum with transverse rugulae in dorsal view (Fig. 6).................................. physothorax

- The posterior portion of pronotum without distinct rugulae in dorsal view (Fig. 7).......................................... onusta

9 Dorsal setae on posterior portion of fourth abdominal tergite directed medially (Fig. 8)................................ difformis

- Dorsal setae on fourth abdominal tergite directed posteriorly (Fig. 9).......................................................................10

10 In lateral view, dorsal profile of promesonotum convex, propodeum distinctly raised relative to promesonotum, metanotal groove very deep................................................................................................................................ sewardi

- In lateral view, dorsal profile of promesonotum convex, propodeum slightly raised relative to promesonotum, metanotal groove not so deep in dorsal median portion................................................................................ ampullaris