Acropyga hystrix

A nest was found in the soil under a log, but otherwise nothing is known of this species' natural history.

Identification
Lapolla (2004) - Worker: 11 segmented antennae; mandible with 6-7 teeth; pronotal and mesonotal dorsa with long erect hairs and a thinner layer of short erect hairs. Queen: As in worker with modifications expected for caste. Male: 12 segmented antennae; parameres broad, tapered to a sharp medial point, with many scattered erect hairs; mandible with 6 teeth. Compare with Acropyga acutiventris and Acropyga gelasis.

This species can be distinguished from Acropyga acutiventris by the lack of ridges on the surface of the mandible, and from Acropyga gelasis by not possessing a prominent "beak-like" median portion of the clypeus. Additionally, the erect mesosomal hairs of A. hystrix are longer than those of A. gelasis. Overall, this species, along with A. gelasis, is darker and with less pilosity than most other Acropyga species.

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

This species is known only from Sarawak on Borneo.

Nomenclature

 *  hystrix. Acropyga hystrix LaPolla, 2004a: 63, figs. 25, 41, 46 (w.q.) BORNEO.

LaPolla (2004) - The species' placement within the myops species-group is based on the fact that A. hystrix workers possess widely separated torulae, and by the fact that the reproductives are very dark (dark brown to black), as are the reproductives of Acropyga myops. The mandibles of this species are similar to A. myops.

Worker
Head: brownish-yellow; darker brownish-yellow toward apex; head slightly longer than broad; posterior margin entire, with distinct long erect hairs scattered throughout; 11 segmented, incrassate antennae; scape reach or surpasses posterior margin by approximately length of pedicel; scape with erect hairs scattered throughout length; clypeus broad and wide, convex medially, with scattered erect hairs throughout; mandible broad, with 6-7 teeth; 3rd tooth from apical usually smaller than others; if with 7 teeth, 7th tooth at meeting of inner mandibular margin and masticatory margin, often smaller than other teeth. Mesosoma: brownish-yellow; in lateral view, pronotum rises steeply toward mesonotum; mesonotum with sparse covering of appressed hairs, long erect hairs posteriorly; mesonotum rounded, slightly higher than level of propodeum, with distinct long, erect hairs on dorsum; metanotal area distinct; propodeal dorsum flat, with sparse short appressed to erect hairs; declivity steep. Gaster: petiole thick and erect, reaching height of propodeal spiracle; gaster brownish-yellow; gaster dorsum slightly darker than venter; covered in layer of short, appressed hairs, though shinier than most other species; scattered erect hairs throughout.

Measurements (n=6): 2.24-2.69; HW: 0.543-0.647; HL: 0.607-0.665; SL: 0.511-0.549; ML: 0.596-0.7; GL: 0.964-1.33; CI: 89.46-96.68; SI: 82.53-90.98.

Queen
As in worker with modifications expected for caste and the following differences: color much darker than observed in worker, becoming almost black.

Measurements (n=2): TL: 3.99-4.00; HW: 0.803-0.813; HL: 0.782-0.799; SL: 0.743; ML: 1.22-1.27; GL: 1.95-1.97; CI: 101.75-102.69; SI: 91.39-92.53.

Male
Head: brownish-yellow; darker toward apex around 3 prominent ocelli; covered in layer of appressed hairs; longer, erect hairs along posterior margin; head about as broad as long; posterolateral comers rounded, giving head an overall round appearance; 12 segmented, slightly incrassate antennae; scapes surpass posterior margin by about length of first 3 funicular segments; clypeus broad, convex medially; mandible broad with 6 teeth; inner mandibular margin parallel with anterior clypeal margin. Mesosoma: brownish-yellow; pronotum small and collar-like, overarched by mesonotum; mesosomal dorsum with appressed hairs and scattered erect hairs; propodeum wide, sloping with an indistinct declivity. Gaster: petiole thick and erect; gaster brownish-yellow, covered in layer of appressed hairs with scattered erect hairs throughout. Genitalia: in lateral view, parameres broad, tapered to short medial points at midheight, with many scattered erect hairs; cuspi taper toward apices with peg-like teeth; cuspi slightly bent toward digiti; digiti erect, thick and apically truncated, with short, peg-like teeth on apices where they meet with cuspi.

Measurements (n=1): TL: 2.68; HW: 0.504; HL: 0.514; SL: 0.415; ML: 0.978; GL: 1.19; CI: 98.05; SI: 82.34.

Type Material
Holotype worker, MALAYSIA: Sarawak, 4th Div., G. Mulu National Park, RGS Expedition, Long Pala, lowland rainforest under a log (B. Bolton) ; 14 paratype workers, paratype queens, paratype males (BMNH). The holotype is labeled JSL TYPE # 110.

Etymology
The specific epithet hystrix is Greek for porcupine in reference to the long, stout erect hairs on the mesosoma.