Temnothorax brevispinosus

Only known from the type, this species was discovered in Michoacan, Mexico. The nest was found in amongst rocks in an open area within a pine-oak forest, in rocky soil.

Identification
Mackay (2000) "This is a small, brown species with a 12-segmented antenna. The propodeal spines are poorly developed, consisting of small, blunt bumps. The head is nearly completely smooth and shiny, as is much of the dorsum of the mesosoma (except propodeum, which has well defmed rugae intermixed with punctures) and the side of the pronotum. The petiolar node has a relatively sharp apex with coarse rugae covering the upper surface.

This new species is nearly identical to Temnothorax mexicanus. It differs in the sculpturing of the workers, females and males. The head of the worker is more coarsely sculptured than that of Temnothorax mexicanus, specifically the striae between the eye and insertion of the antenna are very coarse and well developed, consisting of parallel, semicircular lines with the insertion of the antennae at the center. The side of the pronotum is mostly smooth and glossy, whereas the side of the pronotum of Temnothorax mexicanus is covered with striae. The females are less sculptured than those of Temnothorax mexicanus, the dorsum of the head is nearly smooth and shining, but the semicircular striae are present between the eye and the insertions of the antennae, as in Temnothorax mexicanus. The degree of sculpturing of the workers and females is reversed from the situation in Temnothorax mexicanus: the workers of Temnothorax brevispinosus are more sculptured than those of Temnothorax mexicanus, the females of Temnothorax brevispinosus are less sculptured than those of Temnothorax mexicanus. The propodeal spines of Temnothorax brevispinosus are very poorly developed, much less than Temnothorax mexicanus. The clypeus of the male of Temnothorax brevispinosus is nearly completely covered with reticulated rugae, much more than simply a transverse ruga at the anterior of the clypeus, as appears in Temnothorax mexicanus and Temnothorax adustus. Thus, although these three species are closely related, there are these major structural differences between them. It could be confused with Temnothorax manni. It differs in that the scapes have at least suberect hairs (appressed in Temnothorax manni). Additionally, the propodeal armature consists of poorly developed angles, whereas the angles of Temnothorax manni are nearly developed into spines."

Distribution
MEXICO, Michoacan. Known only from type locality.

This taxon was described from Mexico.

Habitat
The type series was collected in rocky soil in amongst rocks, in pine-oak forest, along road in a somewhat open area.

Abundance
Known only from the type collection.

Worker
Mandibles with 5 teeth; anterior border of clypeus straight and crenulated, clypeus with well developed medial carina and several lateral carinae; vertex nearly straight; sides of head broadly convex; eyes extending past sides of head; antenna with 12 segments; scape nearly reaching occipital corners: mesosoma with dorsum nearly flat, sutures not marked on dorsum; propodeum with dorsal face and posterior face equal in length, propodeal spines consisting of simple angles; petiole with anterior petiolar face nearly straight, posterior face also nearly straight, meeting at the top of the petiolar node at an angle subpeduncular process consisting of a simple tooth; post-petiole not remarkable.

Erect hairs mostly blunt tipped, scattered over head. including c1ypeus. short (up to 0.05mm), scapes with abundant hairs, few nearly erect. most suberect to decumbent, mesosoma with several hairs, mostly on dorsum, short (up to 0.08mm), some nearly clavate. legs with several hairs, many erect, many hairs on petiole and postpetiole, similar to those on mesosoma, gaster with many hairs, some nearly sharp pointed; decumbent pubescence sparse. few hairs on head and gaster.

Sculpture mostly smooth. dorsum of head smooth and glossy, area posterior to insertion of antennae with concentric whorls of rugae, sides of head, especially near base of mandible. with rugae and a few scattered punctures, side and dorsum of pronotum smooth and shining, except for very fine costulae on lower lateral border, mesopleural region and side of propodeum with moderately well defined rugae, intermixed with punctures, top of mesosoma predominantly smooth and shining, dorsum of propodeum similar to side, posterior face with transverse striations, side of petiole with poorly defined rugae and punctures, top of petiole with coarse rugae, side of postpetiole mostly punctate, top smooth on anterior half, posterior half punctate, gaster completely smooth and shining.

Color medium brown.

Measurements: HL 0.65-0.67, HW 0.52-0.53, SL 0.5-0.52, EL 0.13-0.14, WL 0.68-0.70, PW 0.14-0.16, PL 0.13-0.14, PPW 0.20-0.22, PPL 0.16-0.18. Indices: CI 79-80, SI 78, PI 108-114, PPI 122-125.

Queen
Mandible with 5 or 6 teeth (some poorly defined); clypeus as in worker; eyes large, extending well beyond sides of head; ocelli well developed; scape reaching occipital corner; vertex slightly concave; propodeal spines consisting of simple angles; petiole and postpetiole as in worker, except that anterior half of postpetiole rising above surface as swollen area.

Erect hairs on head and mesosoma similar to those of worker, those on petiole, postpetiole and gaster longer (up to 0.18mm) and mostly with sharp points; decumbent pubescence as in worker; sculpture more coarse, specifically rugae on head extend to area between eye and frontal carina, pronotum with striae on sides, mesopleuron mostly smooth and shining, propodeum with coarse rugae with intrarugal spaces partially to mostly shining, petiole, postpetiole and gaster as in worker.

Color medium brown.

Measurements: HL 0.77, HW 0.67, SL 0.61, EL 0.22, WL 1.30, PW 0.22, PL 0.16, PPW 0.32, PPL 23, Indices: CI 87, SI 79, PI 138, PPI 139.

Male
Mandible with 3-5 teeth, most except apical poorly defined; median anterior border of clypeus convex, clypeus convex; eyes large, extending well past sides of head; ocelli large; scape short, approximately length offirst 3 funicular segments; vertex weakly concave; propodeal armature nearly absent, area where spines normally occur simply bulging from surface and connected across propodeum to other bulge by carina; petiole as in worker, but lower and less acute.

Erect hairs sparse, those on head very short (less than 0.04mm), those on mesosoma slightly longer (up to 0.07mm), those on petiole long (0.12mm), gastral hairs slightly shorter (0.10mm): decumbent pubescence very sparse, few hairs only on head.

Sculpture very different than that of worker and female, dorsum and ventral surface of head completely punctate, rugae present near mandibles and near frontal carinae, clypeus with coarse rugae, a major ruga extending transversely across middle ofc1ypeus, a smaller medial ruga extending from anterior margin of c1ypcus to this ruga, other rugae smaller, pronotum glossy with fine costulae on lower surface, scutum moderately shining, surface covered with costulae mesopleural area mostly shining, side of propodeum with costulae, top with fine rugae, posterior face coriaceous, petiole and postpeptiole with fine punctures and costulae, gaster smooth and shining.

Color medium brown.

Measurements: HL 0.46-0.47, HW 0.52-0.53, SL 0.14 0.15, EL 0.22-0.25, WL 1.00-1.01, PW 0.14-0.15, PL 0.11-0.13, PPW 0.20-0.21, PPL 0.11-0.12, Indices: CI 113, SI 30-32, PI 115-127, PPI 175-182.

Type Material
Holotype worker MCZC, 33 paratype workers CWEM, MCZC, MHNG, UNAM, USNM, 1 paratype female MCZC and 3 paratype males CWEM, MCZC, USNM.

Type Locality Information
Michoacan, Parque Nacional Cerro Garnica, 2700 meters, 25 May 1988, W. Mackay #10357. Nest in soil. The site is one mile E of park entrance, 3.2 miles road distance from Pino Gordo, using odometer.

Etymology
Morphological. Name based on the small propodeal spines in all three castes.

Additional References
MacKay, W. P. 2000. A review of the New World ants of the subgenus Myrafant, (Genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology. 36:265-444.