Strumigenys rhadina

Known from a small number of collections, the meager data available (mesic forest habitat litter-samples) suggests this is a ground/litter dwelling species that lives in wet forests.

Identification
Bolton (2000) - A member of the rhadina complex in the Strumigenys caniophanes-group. Only two species in the group have a lamella on the inner margin of the mandible, rhadina and Strumigenys sardella. The latter has standard indices in the same range as the former but is larger and has differently arranged pilosity. S. sardella lacks projecting hairs on the tibiae and basitarsi; it has only 2 freely laterally projecting hairs on the dorsolateral margin of the head, these are short (less than 0.20 X SL) and do not arise from tubercles. Apart from the hairs at the occipital margin the cephalic dorsum of sardella has only a single other pair of standing hairs, near the highest point of the vertex.

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

Nomenclature

 *  rhadina. Strumigenys rhadina Bolton, 2000: 764 (w.) BORNEO.

Worker
Holotype. TL 2.3, HL 0.63, HW 0.51, CI 81, ML 0.25, MI 40, SL 0.30, SI 59, PW 0.30, AL 0.66. Mandible with a stout preapical tooth, the inner margin proximal of the tooth with a prominent cuticular lamella that is broadest near the tooth and tapers basally; maximum width of lamella less than half length of preapical tooth. With head in full-face view the dorsolateral margin with numerous hairs that freely project laterally; 5-7 of these are relatively long (0.35-0.50 X SL) and arise from small but distinct tubercles, the remainder are shorter. Cephalic dorsum with erect hairs present from posterior margin of clypeus to occipital margin. Pronotal humeral hair long, weakly flagellate. Promesonotal dorsum with numerous erect hairs, those lining the dorsolateral margin arising from distinct tubercles. Waist segments and first gastral tergite with numerous standing hairs that are similar to those on the promesonotum. All standing hairs are stiffly filiform and simple, mostly acute apically. Middle and hind tibiae and basitarsi with projecting long hairs present. Dorsal surfaces of femora without erect hairs. Pleurae and side of propodeum unsculptured and smooth except for extreme periphery. Petiole node in dorsal view slightly broader than long. In profile the node with a steep anterior face that is longer than the dorsum, the latter short and rounding evenly into a shallowly sloping longer posterior surface.

Paratype. TL 2.3, HL 0.65, HW 0.51, CI 78, ML 0.25, MI 38, SL 0.30, SI 59, PW 0.30, AL 0.66.

Type Material
Holotype worker, Malaysia: Sarawak, Santubong, Kuching, v. 1994 (Lobl & Burckhardt).

Paratype. 1 worker with same data as holotype.

References based on Global Ant Biodiversity Informatics

 * 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
 * Woodcock P., D. P. Edwards, T. M. Fayle, R. J. Newton, C. Vun Khen, S. H. Bottrell, and K. C. Hamer. 2011. The conservation value of South East Asia's highly degraded forests: evidence from leaf-litter ants. Phil. Trans. R. Soc. B. 366: 3256-3264.
 * Woodcock P., D.P. Edwards, T.M. Fayle, R.J. Newton, C. Vun Khen, S.H. Bottrell, and K.C. Hamer. 2011. The conservation value of South East Asia's highly degraded forests: evidence from leaf-litter ants. Phil. Trans. R. Soc. B 366: 3256-3264.