Temnothorax rugulosus

Known only from the holotype worker.

Identification
Mackay (2000) - This is a light brown species with fine rugae covering the entire dorsum of the head and the mesosoma, and the peduncle has a well-developed tooth. The antenna has 12 segments. The hairs on the scape are suberect. The subpeduncular process is well developed.

This species could be confused with Temnothorax carinatus or Temnothorax neomexicanus. It differs from both by having fine rugulae on the tops and sides of the mesosoma (the other two species are primarily punctate on these surfaces). The sculpture on the dorsum of the mesosoma of Temnothorax neomexicanus is somewhat rugose (with weak foveolate punctures), but Temnothorax rugulosus is yellow-brown, Temnothorax neomexicanus is black (or dark brown). The subpeduncular process of Temnothorax rugulosus is developed into an elongate tooth, whereas the process of Temnothorax neomexicanus is a tiny tooth. The hairs on the scape are raised from the surface, nearly suberect. Similar hairs in Temnothorax neomexicanus and Temnothorax carinatus are completely decumbent. This new species differs from Temnothorax rugithorax as the propodeal spines are more developed, and the rugulae on the dorsum of the pronotum extend posteriorly onto the dorsum of the mesonotum.

Distribution
Mexico. Michoacan.

Habitat
Oak-pine-Crataegus litter

Abundance
Only known from types.

Caste
Known only from the worker caste.

Nomenclature

 *  rugulosus. Leptothorax (Myrafant) rugulosus Mackay, W.P., 2000: 401, figs. 58, 60, 161, 162 (w.) MEXICO. Combination in Temnothorax: Bolton, 2003: 272.

Worker
Mandibles with 5 teeth, basal most tiny; anterior border of clypeus slightly concave, clypeus with several delicate carinae, including a medial carina; vertex slightly concave; mesosoma with out any of the sutures breaking surface; propodeal angles small and weakly developed; petiolar peduncle with well developed ventral tooth, petiolar node rounded in profile, blunt. Erect hairs scattered on all surfaces, up to 0.06mm in length, blunt tipped but not spatulate, finer hairs on scapes and legs nearly decumbent.

Sculpture characteristic, consisting of fine, longitudinal rugae on dorsum of the head, which diverge on vertex, becoming nearly parallel with nuchal collar, those near eye forming poorly defined concentric circles, concentric semicircles posterior to insertions of antennae, rugae on sides of pronotum and mesopleural area coarse, other rugae on mesosoma poorly defined and mixed with coarse punctures, most rugae on dorsum of mesosoma longitudinal and mixed with punctures, rugae on dorsal face of propodeum longitudinal, extending between teeth and meeting and forming a perpendicular angle with transverse striae on the descending face, dorsum of petiole with coarse rugae mixed with punctures, node of postpetiole mostly punctate, sides of petiole and postpetiole with rugae mixed with punctures, gaster smooth and shining. The gaster is essentially the only part ofthis ant not covered by dense, coarse sculpture, although the intrarugal spaces on head, the clypeus and a small area posterior to frontal area are also somewhat smooth and shining.

Color: light brown.

Worker measurement (mm): HL 0.68, HW 0.59, SL 0.58, EL 0.16, WL 0.79, PW 0.19, PL 0.23, PPW 0.28, PPL 0.18. Indices: CI 87, SI 85, PI 83, PPI 156.

Type Material
MEXICO: Michoacan, 10.5 KN Cheran, 28-vii-1988, 2255 meters, R. Anderson #88-9. Holotype worker.

Etymology
Morphological. "Diminutive of ruga, Latin for wrinkle, referring to the fine rugae on the head. "