Stictoponera biroi

This rainforest species is known from New Guinea (both West Papua and Papua New Guinea) with a limited number of collections from extreme northern Australia. It forms small colonies in rotten logs.

Identification
Head subquadrate in frontal view, without occipital lobes; occipital lamella well developed, convex. Petiolar node with small, narrow anteriorly projecting ventral process in lateral view. Dorsum of abdominal segment 4 varying from longitudinally costulate to mostly smooth with scattered punctae, some punctae elongate with brief longitudinal crests, posterolateral margins with brief longitudinal strigulae.

G. biroi keys out close to Gnamptogenys grammodes and may be closely related to it based on similarities in the occipital lamella and the shape of the subpetiolar process. The postpetiolar dorsum of G. grammodes differs from that of G. biroi in having a posterior strip of longitudinal carinulae and smoother cuticle anterad with punctae and no foveolae as in G. biroi. G. grammodes has a mostly smooth fourth abdominal tergite and is a smaller ant (HL > 1.2 mm;WL > 1.60 mm) than G. biroi.

Distribution
This taxon was described from New Guinea. It is also known from Cape York Peninsula, Australia.

Biology
This is the only species of Gnamptogenys found in Australia, where the genus Rhytidoponera Mayr is the dominant ectatommine. Nests and individuals of G. biroi have been recorded from rotten wood in rainforest and secondary lowland forest.

Worker
Metrics (n = 5): HL 1.25-1.38, HW 1.05-1.19, ML 0.62-0.73, SL 1.10-1.20, ED 0.28-0.39, WL 1.78-1.98 mm. CI 0.82-0.88, SI 0.99-1.08, MI 0.57-0.66, OI 0.27-0.34.

Head subquadrate in frontal view, lateral margins relatively straight, posterior margin straight to slightly concave, posterolaterally rounded, anterior margin of clypeal lamella projecting anterad into blunt point with slightly sinuate sides; frons densely foveolate with fine strigae frequently present on cuticle between foveolae; clypeus longitudinally costulate; vertex foveolate along anterior margin, mostly smooth posterad and bound by sulcus. Scape varies from mostly smooth to longitudinally strigulose; eye relatively large; no occipital lobes; occipital lamella well developed, convex. Lateral mesosoma mostly densely foveolate; mesosomal dorsum densely foevolate; anepisterum cuneiform; metapleuron with some longitudinal costulae posteroventrally; propodeal declivity depressed, mostly smooth, sometimes with longitudinal low costulae or rugosity. Petiolar node with small, narrow anteriorly projecting ventral process in lateral view, dorsum foveolate; postpetiolar dorsum longitudinally foveolate to rugulose-foveolate, foveolae round anterad, becoming progressively more elongate posterad; sternum undulate with transverse strigulae, especially anterad, sternum laterally foveolate; dorsum of abdominal segment 4 varies from longitudinally costulate to mostly smooth with scattered punctae, some punctae elongate and with brief longitudinal crests, posterolateral margins with brief longitudinal strigulae. Fore coxa varies from mostly smooth to moderately transversely strigulose in lateral view, most strigulae concentrated apically; fore tarsus opposite strigil with single stout setae, followed apically by row of smaller setae. Dorsum of thorax and abdominal segments 1-4 with abundant erect to subdecumbent hairs. Head, mesosoma, petiole, and gaster brown; mandibles, antennae, legs ferruginous.

Queen
Metrics (n = 2): HL 1.28, 1.42; HW 1.14, 1.23; ML 0.66, 0.75; SL 1.14, 1.38; ED 0.39, 0.40; WL 2.02, 2.22 mm. CI 0.89, 0.87; SI 1.00, 1.12; MI 0.58, 0.61; OI 0.35, 0.33.

Pronotum densely foveolate, occasionally with median smooth area; mesoscutum longitudinally rugose-punctate; anepisternum with variable degree of longitudinal strigulae and smooth areas; katepisternum foevolate, posterad frequently with finely strigulose cuticle or mostly foveolate; scutellum densely foveolate to strigulose-punctate; propodeum densely foveolate.

Male
Metrics (n = 1): HL 0.90, HW 0.83, ML 0.49, SL 0.47, ED 0.35, WL 1.66 mm. CI 0.92, SI 0.57, MI 0.59, OI 0.42.

Frons with low irregular rugulae and large patches of undulate sculpturing, foveolae tend to be areolate posterolaterally in frontal view; frons with fine longitudinal carina extending posterad from posteromedian clypeal margin to eye level in frontal view; clypeus separated from frons by broad sulcus, three ridges cross sulcus joining frons with clypeus; clypeus mostly undulate with scattered strigulae, lamella converging to blunt angle along anterior margin. Pronotum with shallow, flat-bottomed and undulate foveolae, with smooth cuticle between foveolae; mesopleuron mostly smooth with scattered punctae; mesoscutum foveolate, scutellum rugulose-foveolate; propodeum areolate; petiolar node strigulose. Postpetiole mostly smooth with undulations, especially anterolaterally; fourth abdominal tergite smooth.