Pristomyrmex umbripennis

This species occurs in rainforest and has been collected in and on rotten logs and under loose bark of a log.

Identification
Wang (2003) - Worker. Masticatory margin of mandible with four teeth (an apical + a preapical + two broad-based short teeth of similar size), lacking a distinct diastema; eyes generally with six to seven (rarely five) ommatidia in the longest row; propodeum with a pair of elongate triangular teeth.

It is closely related to Pristomyrmex pollux and Pristomyrmex picteti, but their workers and queens can be separated by the following characters: P. umbripennis- Eyes larger, generally consisting of 20 or more ommatidia and containing six to seven (rarely five) ommatidia in the longest row (worker). Propodeum with a pair of triangular toothlike armaments that are shorter than the distance between their bases (worker and queen). One-third to one-half of the antennal scape usually laterally compressed near the base (worker and queen). P. pollux and P. picteti - Eyes smaller, generally consisting of 10 or less ommatidia, and containing two to three (rarely four) ommatidia in the longest row (worker). Propodeum with a pair of fairly long or long spines that are longer (or much longer) than the distance between their bases (worker) or with a pair of short spines (queen). Antennal scape not laterally compressed near the base (worker and queen).

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

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

Nomenclature

 *  umbripennis. Myrmica umbripennis Smith, F. 1863: 21 (q.) INDONESIA (Misool I.). Combination in Pristomyrmex: Donisthorpe, 1932c: 471. Senior synonym of castaneicolor, castor, laevis, parumpunctatus: Wang, M. 2003: 525.
 * laevis. Solenopsis laevis Smith, F. 1865: 75 (w.) INDONESIA (Morotai I.). Combination in Pheidologeton: Emery, 1924d: 213; in Pristomyrmex: Donisthorpe, 1932c: 473. Junior synonym of umbripennis: Wang, M. 2003: 525.
 * parumpunctatus. Pristomyrmex parumpunctatus Emery, 1887b: 452 (w.q.) NEW GUINEA. Junior synonym of umbripennis: Wang, M. 2003: 525.
 * castor. Pristomyrmex castor Donisthorpe, 1944d: 81 (q.m.) NEW GUINEA. Junior synonym of umbripennis: Wang, M. 2003: 525.
 * castaneicolor. Pristomyrmex castaneicolor Donisthorpe, 1949g: 412 (w.) NEW GUINEA. Junior synonym of umbripennis: Wang, M. 2003: 525.

Worker
Wang (2003) - TL 5.48-7.06, HL 1.32-1.68, HW 1.30-1.74, CI 98-109, SL 1.20-1.52, SI 81-92, EL 0.12-0.18, PW 0.86-1.16, AL l.46-l.88, PPW 0.33- 0.47, PPL 0.32-0.44, PPI 103-113 (n = 52).

Mandibles with a few longitudinal rugae that often reach to the masticatory margin. Basal margin of mandible with a central, broadly curved prominence. Clypeus smooth and shining with a strong median longitudinal carina. Anterior clypeal margin usually with seven denticles: a median denticle and three others on each side; sometimes one to two lateral denticles are indistinct; sometimes, two lateral denticles are fused into a broad lobe. Ventral surface of clypeus with a coarse transverse ridge. Palp formula 1,3. Frontal carinae extending to the level of the posterior margins of eyes. Antennal scrobes absent. Frontal lobes present, partially covering the condylar bulbs of holding antennal scapes. One third to one half of the antennal scapes usually laterally compressed near the bases. Antennal scapes, when lying on the dorsal head, just beyond the occipital margin. Lamella encircling the base of the antennal scape with a broad and deep notch on the center of the dorsal surface. Eyes gene rally containing more than 20 (rarely 15) ommatidia, with six to seven (rarely five) in the longest row. Occipital margin straight or feebly concave in full-face view. Alitrunk, in profile, with a convex dorsum, in dorsal view without any sutures. Pronotum unarmed. Propodeum with a pair of slightly elongate triangular teeth. Metapleural lobes prominent and rounded. Petiole node in profile longer than high with a long anterior peduncle; its anterodorsal angle is on approximately the same level as the posterodorsal. Subpetiole with a narrow, semitranslucent lamella. Postpetiole in profile higher than long, rounded dorsally, in dorsal view slightly broadening from front to back. Dorsal surfaces of head and alitrunk and the sides of pronotum with scattered foveolate punctures, varying from shallow, small, and few to distinct, rather large and many; space between foveolae usually smooth. Petiole, postpetiole, and gaster smooth and shining. Dorsal surfaces of head and alitrunk with some erect or suberect short hairs. Usually two to three pairs of hairs present on the dorsal surfaces of petiole node and postpetiole, respectively. A row of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with numerous suberect short hairs. First gastral tergite lacking erect or suberect hairs. Color reddish-brown, but the masticatory margin of mandible black-brown.

Queen
Wang (2003) - TL 8.00-8.25, HL 1.80-2.02, HW 2.00-2.25, CI 99-118, SL 1.52-1.6.5, SI 73-79, EL 0.40-0.42, PW 1.50-1.60, AL 2.26-2.40, PPW 0.52-0.52, PPL 0.48-0.50, PPI 104-108 (n = 4).

General shape with normal caste differences from the conspecific worker; propodeal armaments toothlike; other characters similar to worker.

Male
Wang (2003) - A single male specimen (BMNH), collected in Papua (Kokoda, 1,200 ft) by L. E. Cheeman in August 1933, has the following measurements: TL ca. 6.04, HL 0.94, HW 0.98, CI 104, SL 0.3.5, SI 36, EL 0.47, P\;V 1.28, AL 1.98.

Head, including the eyes, distinctly broader than long. Clypeus narrow, transverse, convex in the middle, its anterior margin almost straight. Frontal carinae short. Eyes large and prominent. On the mesoscutum, notauli rather wide, forming a Y shape with several coarse rugae. Scutoscutellar sulcus wide, separated into small cells by longitudinal ridges. Propodeum armed with a pair of strong triangular teeth. Metapleural lobes rounded. Petiole node in profile low, distinctly longer than high, with a long anterior peduncle. Postpetiole in profile slightly longer than high and rounded dorsally. Dorsum of head behind the level of the posterior margins of eyes with some foveolate-reticulate sculpture, but the centrical disc of the dorsal head, under the median ocellus, smooth and shining. Each side of the dorsal head, between the eye and the frontal carina, with several transverse rugae; spaces between the rugae smooth and shining. Promesonotum with somewhat coarse foveolate-reticulate sculpture. Sides of petiole node with foveolate-reticulate sculpture. Postpetiole rather smooth, only with few superficial short rugae on each side. Gaster unsculptured, smooth, and shining. Body blackish-brown, but gaster and scapes reddish-brown.

Type Material
Myrmica umbripennis

Holotype queen in. Labelled “M” (= Misool I.).

Solenopsis laevis

Holotype worker in. Labelled “M.” (= Morotai I.). Three other specimens, labelled “Morty Isld” are also present in, but these appear to originate in a different series from the holotype. In addition, three more workers from this series are in.

Wang (2003) - Holotype queen, Indonesia: Mysol (A. R. Wallace) [examined].

Solenopsis laevis Holotype worker, Indonesia: Morty Island (A. R. Wallace) (OXUM) [examined].

Pristomyrmex parumpunctatus Lectotype worker, New Guinea: Andai (L. M. D'Albertis), here designated, [examined].

Pristomyrmex castor Lectotype queen, New Guinea: Papua, Kokoda, 1,200 ft, x.1933 (L. E. Cheesman) (BMNH), here designated, [examined].

Pristomyrmex castaneicolor Syntype workers, New Guinea: Maffin Bay, ix-1944 (E. S. Ross) (BMNH,, , , ) [examined].