Crematogaster tanakai

This species was collected together with Crematogaster difformis nesting within the epiphyte Platycerium sp., suggesting the possibility that it might be associated with C. (P.) difformis.

Identification
This species is unique among the Asian Crematogaster ants in having a swollen dorsal median portion of the head.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia.

Nomenclature

 *  tanakai. Crematogaster (Physocrema) tanakai Hosoishi & Ogata, 2009b: 29, figs. 18, 30 (w.m.) BORNEO.

Worker
HW 1.66; HL 1.52; CI 109; SL 0.98; SI 59; EL 0.26; PW 0.74; WL 1.42; PSL 0; PtL 0.4; PtW 0.34; PtH 0.24; PpL 0.24; PpW 0.34; PtHI 60; PtWI 85; PpWI 142; WI 100 (one worker measured).

Scape not reaching posterior corner of head. Dorsal median portion of the head swollen.

In lateral view, promesonotum convex; mesonotum differentiated from pronotum; propodeum slightly raised relative to promesonotum. Anterior margin of pronotal collar slightly concave in dorsal view. Promesonotal suture visible. Metanotal groove convex posteriorly in dorsal view, 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 reticulate rugulae. Reticulate rugulae on pronotum and propodeum.

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 suberect and appressed setae. Dorsal setae on posterior portion of fourth abdominal tergite directed medially.

Head red, mesosoma and gaster brown.

Type Material
HOLOTYPE worker from MALAYSIA: Lambir N. P., Miri, Sarawak, Borneo, 28. ix. 2005 (H. Tanaka) from the epiphyte Platycerium sp. (FRC). Paratypes. 1 male, same data as holotype (FRC).

References based on Global Ant Biodiversity Informatics

 * Hosoichi S., and K. Ogata. 2009. A taxonomic revision of the Asian endemic subgenus Physocrema of the genus Crematogaster (Hymenoptera: Formicidae). Zootaxa 2062: 15-36.
 * Hosoishi S. and K. Ogata. 2009. A check list of the ant genus Crematogaster in Asia (Hymenoptera: Formicidae). Bull. Inst. Trop. Agr. Kyushu Univ. 32: 43-83.
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58