Strumigenys gnathosphax

Known from wet-forest litter samples.

Identification
Bolton (2000) - A member of the Strumigenys wallacei-group. This stocky, broad-headed species is unique in the group as it has two intercalary denticles and a scrobe that is well developed behind the level of the eye. Its scape is quite short, SI 56-59 as opposed to SI 67-85 in Strumigenys diasphax and Strumigenys wallacei together. S. gnathosphax also separates easily from diasphax as that species has numerous standing hairs on both head and promesonotum, and from wallacei as the latter has the side of the alitrunk and disc of the postpetiole reticulate-punctate, and its mesonotum bulges and has an almost vertical posterior declivity.

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

Nomenclature

 *  gnathosphax. Strumigenys gnathosphax Bolton, 2000: 911, fig. 481 (w.) WEST MALAYSIA.

Worker
Holotype. TL 2.8, HL 0.80, HW 0.75, CI 94, ML 0.40, MI 50, SL 0.44, SI 59, PW 0.36, AL 0.78. Apical fork of mandible with 2 intercalary denticles. Scrobe in profile conspicuous behind level of eye. Declivity of propodeum armed with a narrow spine dorsally and a projecting weakly spongiform lobe ventrally, the two connected by a weak carina. Ventral spongiform curtain of petiole at deepest distinctly greater than half the depth of the peduncle. Dorsal surface of head without standing hairs, with dense strongly curved spatulate ground-pilosity that is weakly or not elevated. Appressed anteriorly curved hairs that fringe upper scrobe margin minute, much smaller than hairs on leading edge of scape. Dorsolateral margin of head without projecting hairs. Pronotal humeral hair short, stout and clavate. Dorsum of pronotum with spatulate ground-pilosity as on head. Mesonotum with similar hairs but posteriorly they are more elevated and one or more posterior pairs are longer, more erect and more obviously clavate apically. Waist segments and first gastral tergite with stout stiff remiform to clavate hairs, those on gaster suberect to erect. Pleurae and side of propodeum mostly to entirely smooth; disc of postpetiole not reticulate-punctate.

Paratypes. TL 2.7-2.8, HL 0.73-0.80, HW 0.68-0.75, CI 93-96, ML 0.36-0.40, MI 47-50, SL 0.40-0.44, SI 56-59, PW 0.34-0.37, AL 0.72-0.78 (6 measured).

Type Material
Holotype worker, Malaysia: Cameron Highlands, 22.iii.1984 (Rougemont). Paratypes. 2 workers with same data as holotype; 10 workers, Malaysia: Pahang, Fraser’s Hill, 1380 m., Kuantun ridge, 17.iii.1993, #8 (Lobl & Calame) (BMNH,, ).

References based on Global Ant Biodiversity Informatics

 * Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
 * 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