Pristomyrmex inermis

This species occurs in rainforest and has been collected in litter samples and on logs.

Identification
Wang (2003) – Worker. Propodeum lacking a pair of teeth or spines and this makes this species easily recognized. This is unique within Pristomyrmex. In addition, in the levigatus group, P. inermis has a characteristic shape of the petiole node in the workers and queens: wedge like in profile view with an apex. This character has originated independently at least twice in the genus because it is also seen in Pristomyrmex fossulatus and Pristomyrmex punctatus of the punctatus group.

A member of the Levigatus species group / Key to Pristomyrmex workers

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia, New Guinea.

Castes
Males have yet to be collected.

Nomenclature

 *  inermis. Pristomyrmex inermis Wang, M. 2003: 496, figs. 209-212 (w.q.) NEW GUINEA.

Worker
Holotype. TL 2.86, HL 0.72, HW 0.70, CI 97, SL 0.64, SI 91, EL 0.14, PW 0.50, AL 0.72.

TL 2.65-3.36, HL 0.70-0.84, HW 0.69-0.84, CI 96-103, SL 0.62-0.76, SI 83-92, EL 0.12-0.16, PW 0.46-0.58, AL 0.63-0.80, PPW 0.23-0.27, PPL 0.17-0.21, PPI 128- 142 (n = 18).

Mandibles smooth and shining but sometimes with a few superficial small punctures. Masticatory margin of mandible with four teeth arranged as the strongest apical + the second strongest preapical + the smallest third + a basal tooth; a distinct diastema lacking. A broad-based triangular short tooth present about midway on the basal margin of mandible. Frontal area concave. Clypeus flat, smooth, and shining, its anterior margin with three denticles: a weak median tooth and one on each side, but sometimes the median tooth indistinct or lacking so that only two teeth are present there. Ventral surface of clypeus lacking any distinct rugae or teeth. Palp formula 1,3. Frontal carinae just extending to the level of the posterior margins of the eye s. Antennal scrobes absent. Frontal lobes very weak. Eyes moderately sized. Occipital margin feebly convex in full face view. Dorsum of alitrunk in profile arched. Pronotum unarmed. Propodeum lacking a pair of teeth or spines but usually with a pair of blunt small tubercles. Metapleural lobes small, usually bluntly rounded, but sometimes toothlike. Petiole node in profile wedge shaped, usually with a blunt triangular apex; sometimes the apex somewhat bluntly rounded. Subpetiole with a narrow rim. Postpetiole in profile slightly higher than the petiole node, with a convex dorsum. In dorsal view, petiole node and postpetiole broader than long. Cephalic dorsum between the frontal carinae highly polished but usually with a few foveolate punctures bordering frontal carinae. A few foveolate punctures present on the genae and many on the ventral surface of the head. Dorsum of alitrunk, petiole, and postpetiole smooth and shining. Gaster unsculptured. Dorsal surfaces of head, alitrunk, petiole, and postpetiole with sparse erect to suberect hairs. A few hairs present on the first gastral tergite. A few pairs of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with some suberect hairs. Color varying from light yellow-brown to blackish-brown, gaster usually darker than alitrunk; sometimes alitrunk lighter than head and gaster so that the specimens show a bicolored form.

Queen
TL 3.23-3.52, HL 0.80-0.81, HW 0.76-0.85, CI 95-106, SL 0.66-0.74, SI 87-92, EL 0.18-0.20, PW 0.64-0.72, AL 0.86-0.94, PPW 0.26-0.30, PPL 0.18-0.24, PPI 125-144 (n = 3).

General shape except for normal caste differences, other characters similar to worker.

Type Material
Holotype Worker. . Indonesia: Irian Jaya, PT. Freeport Concession, Siewa Camp., 03.04°S 136.38°E, 200 ft, lowland secondary rainforest, #98-71 (stray foragers in leaf litter), 12.iv.1998 (R. R. Snelling). Paratypes. 17 workers and three queens (, LACM,, ). Papua New Guinea, New Guinea.