Aenictus biroi

The type colony was "in a bare area, [from] a very populous nest excavated in hard clay soil."

Identification
This species is similar to Aenictus camposi in the angulate propodeal junction, dense punctuation on mesothorax and propodeum, and unarmed subpetiolar process. In A. biroi, However, the body is slightly larger than in A. composi, and the head is almost as long as broad (in the latter the head is clearly longer than broad), and the declivity of the propodeum is broader and widely rounded above (in the latter it is narrow and distinctly tapers above).

A member of the wroughtonii group.

Key to Aenictus species groups

Distribution based on Regional Taxon Lists
Oriental Region: Sri Lanka.

Nomenclature

 *  biroi. Aenictus biroi Forel, 1907a: 10 (w.) SRI LANKA. See also: Wilson, 1964a: 451; Jaitrong, et al. 2010: 37.

Worker
Wilson (1964) - (Syntype: HW 0.59 mm, HL 0.70 mm, SL 0.67 mm. Antenna 10-segmented. Mandible typical. Clypeus convex, entire, unarmed. Parafrontal ridge indistinct, only 0.15 mm long. Basal face of propodeum seen from side strongly convex. Propodeal junction right-angular. Subpetiolar process a low lobe located beneath anterior 1/2 of node. Pilosity relatively sparse and short; length of longest pronotal hairs only 0.10 mm.

Head shining. Mesopleuron and propodeum microreticulate and opaque; remainder of mesosoma shining. Pedicel shining.

Jaitrong et al. (2010) - Measurements. Worker lectotype and paralectotypes (n = 4): TL 3.1-3.2 mm; HL 0.60-0.65 mm; HW 0.50 mm; SL 0.63-0.65 mm; ML 1.08 mm; MTL 0.63-0.65 mm; PL 0.23-0.25 mm, CI 85; SI 114-118.

Head in full-face view slightly longer than broad, with its sides and posterior margin roundly convex: posterolateral corner round. Antennal scape long, almost as long as head length; antennal segment II nearly as long as III; IV-VI almost the same in length, and each slightly shorter than III; VII-IX each slightly longer and broader than VI; the last (X) almost as long as VIII and IX combined. Frontal carina well developed, thin and extending: posteriorly beyond the level of posterior margin of torulus: seen in profile its dorsal outline concave in the middle. Clypeus short, slightly protruding anteriad, with its anterior margin almost straight, bearing 6-8 denticles. Mandible with the apical tooth large and curved, followed by a series of 8-10 minute teeth on masticatory margin. Mesosoma relatively thick, seen from above broader ventrally and constricted at mesothorax: in profile pronotum convex dorsally and sloping gradually to metanotal groove; mesopleuron clearly demarcated from metapleuron by a ridge: upper portion of mesopleuron slightly impressed. Propodeum in profile lower than promesonotum, with nearly straight dorsal outline that slopes down posteriad: area below spiracle impressed, propodeal junction angulate; declivity of propodeum widely and shallowly concave encircled with a thin rim. Petiole slightly longer than high, elevated posteriorly; subpetiolar process present; its ventral outline strongly convex, without angle or tooth: postpetiolar node short, almost as long as broad.

Head and antennal scape smooth and shiny. Pronotum smooth and shiny, with its anteriormost portion punctate; mesothorax and propodeum with dense punctures; propodeal dorsum with short longitudinal rugae along the angle. Petiole extensively smooth and shiny, with its anteriormost part sparsely punctate: postpetiole almost smooth and shiny. Gaster, femora and tibiae smooth and shiny.

Body with relatively sparse standing hairs mixed with sparse short hairs over the surface; length of the longest pronotal hair 0.18-0.20 mm. Head, waist, gaster, antenna and legs yellow: mesosoma pale brown.

Type Material
Jaitrong et al. (2010) - Four syntype workers (one on a pin, three on another) from Pattipola (2,000 m), Ceylon [Sri Lanka] (, examined). The single specimen mounted on one pin is selected as the lectotype, the others as paralectotypes.