Acropyga pallida

Acropyga pallida is found in a range of habitats from dry sclerophyll and Callitris woodlands to rainforests. Nests are in soil, in litter, under stones and in rotten wood.

Identification
Lapolla (2004) - Worker: 9-11 segmented antennae; 5-7 mandibular teeth; inner mandibular margin and basal tooth margin are even with each other; no diastema between the 4th tooth and the basal tooth. Queen: as in worker with modifications expected for caste. Male: in lateral view, parameres become thinner tapering to pointed tips; digiti truncated, slightly longer than cuspi; digiti meet cuspi at apices. Compare with Acropyga ambigua.

This species can be difficult to distinguish from Acropyga ambigua, see discussion there for diagnostic characters. As defined here this species displays considerable variation in mandibular tooth number and mandibular shape, causing some difficulty in determining the boundary of this species. The two most important diagnostic characters are from the mandible: the inner margin and basal tooth margin are even with each other, and there is no diastema between the 4th tooth and the basal tooth (as in A. ambigua). When 6 or 7 teeth are present these additional teeth are found along the inner mandibular margin and smooth out the masticatory margin, making it less square in appearance in full frontal view.

Australia
This species can be separated from other Australian species by the presence of short erect hairs on the scapes and mesosomal dorsum and the small size (head width less than 0.6mm).

Keys

 * Key to Australian Acropyga Species
 * Key to Old World Acropyga Workers / Queens / Males

Distribution based on Regional Taxon Lists
Australasian Region: Australia. Indo-Australian Region: Borneo, Indonesia, Malaysia, New Guinea, Philippines, Solomon Islands.

From LaPolla (2004): This species ranges from Australia, north to the Philippines, and west to Borneo.

Morphology
LaPolla (2004) - While outside of Australia only 5-toothed specimens were examined, within Australia the full range of possible teeth known to occur in this species was observed (5-7 teeth). Whether this is an artifact of collecting (most specimens examined were from Australia), indicative of a latitudinal gradient, or means there is more than one species present remains unclear and the observation warrants further investigation. Since males are known only from Australia, collections in other portions of this species' range will be helpful in clarifying questions about conspecificity.

Nomenclature

 *  pallida. Bothriomyrmex pallidus Donisthorpe, 1938d: 598 (w.) NEW GUINEA. LaPolla, 2004a: 70 (q.m.). Combination in Acropyga: Shattuck, 1992c: 60.

Description
From LaPolla (2004) - Head: yellow; covered in layer of appressed hairs; distinctly longer than broad; posterior margin entire to slightly concave medially; 9-11 segmented, incrassate antennae; scape fails to reach posterior margin by about length of first two funicular segments; clypeus narrow, convex medially, with many erect hairs; mandible broad, tooth number variable with 5-7 approximately equally sized teeth; when 7 teeth present, additional (6th and 7th) teeth along inner mandibular margin usually smaller and found along inner mandibular margin; inner mandibular margin and clypeal margin nearly parallel. Mesosoma: yellow; in lateral view, pronotum with short anterior shelf, then rising toward mesonotum; erect hairs along posterior portion of pronotum; mesonotum variable from flat (at about level of propodeum) to rising above level of propodeum; mesonotum covered in layer of appressed hairs, with scattered erect hairs; metanotal area often distinct; propodeum flat, with layer of appressed hairs; declivity steep. Gaster: petiole thick and erect, reaching level of anterior portion of propodeal spriacle; gaster yellow; covered in dense layer of appressed hairs, with scattered erect hairs throughout.

Measurements (n=17): TL: 1.4-2.06; HW: 0.352-0.447; HL: 0.372-0.519; SL: 0.228-0.363; ML: 0.365-0.495; GL: 0.62-1.06; CI: 82.88-94.89; SI: 64.59-84.92.

Queen
From LaPolla (2004) - As in worker with modifications expected for caste.

Measurements (n=3): TL: 2.55-2.91; HW: 0.504-0.543; HL: 0.519-0.580; SL: 0.412-0.452; SL: 0.412-0.452; ML: 0.831-0.998; GL: 1.2-1.44; CI: 91.49-93.11; SI: 81.75-85.77.

Male
From LaPolla (2004) - Head: brownish-yellow, darker toward apex around 3 prominent ocelli; covered in layer of appressed hairs; head about as broad as long, becoming narrower toward apex; eyes large, breaking outline of head in full frontal view; 12 segmented, incrassate antennae; scape reaches posterior margin; clypeus narrow, convex medially; mandible broad with 4-5 teeth. Mesosoma: brownish-yellow; pronotum short and collar-like, overarched by mesonotum; mesonotum rounded anteriorly; dorsum flat with appressed hairs; propodeum short and low; declivity short and indistinct. Gaster: petiole thick and erect reaching height of propodeum; gaster brownish-yellow; covered in a layer of appressed hairs with scattered erect hairs throughout. Genitalia: in lateral view parameres taper to caudal points; digiti slightly longer than cuspi, with truncated apices; short peg-like teeth at apex of digiti; cuspi meet digiti at apices; cuspi with short peg-like teeth at apices.

(n=1): TL: 1.75; HW: 0.352; HL: 0.361; SL: 0.304; ML: 0.633; GL: 0.754; CI: 97.51; SI: 86.36.

Type Material
Bothriomyrmex pallidus Holotype worker, INDONESIA: Cyclops Mountains, Mt. Lina, elev. 3,500 ft. (L.E. Chessman) (BMNH). Paratype workers, same collecting information, 1 in, 1 in ).