Temnothorax bristoli

Only two workers of this species are known. One was collected in a pitfall trap in Chihuahan Desert scrub and the other at a ground bait in arid pine/juniper forest.

Identification
Prebus 2017 - A member of the sallei clade.

Mackay (2000) - This is a small, black species in which the dorsum of the head is completely shining, and the top of the mesosoma is mostly smooth and shining, but with poorly defined, very weak rugulae, the side of the pronotum is mostly smooth and shining (with weak striae), but the side of the mesosoma is densely punctate, the propodeal spines are very small and the petiolar node is blunt and rounded. The antenna has 12 segments.

This species is most similar to Temnothorax manni, differing in that the side of the mesosoma is densely punctate, not rugose as in Temnothorax manni. It is one of the few species found in the United States in which the dorsum of the head is smooth and polished. It is unlikely to be confused with any other species. It can be easily distinguished from the similar Temnothorax punctithorax by the nearly smooth pronotum (side is roughly sculptured in Temnothorax punctithorax).

Distribution
MEXICO, USA. Southwestern Texas and southern Coahuila.

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.

Habitat
Known from Chihuahuan Desert scrub and arid pine/juniper forest.

Abundance
Only two workers, from two collections, are known for this species.

Nomenclature

 *  bristoli. Leptothorax (Myrafant) bristoli Mackay, W.P., 2000: 326, figs. 28, 96 (w.) U.S.A. Combination in Temnothorax: Bolton, 2003: 271.

Worker
Mandible with 5 teeth; anterior border of clypeus convex, clypeus with poorly defined medial carina and 2 or 3 lateral carinae on each side, most of surface smooth and polished; sides of head nearly straight and parallel; vertex very slightly concave; mesosoma without sutures which break sculpture; propodeal angles very tiny and poorly developed; peduncle of petiole with very tiny ventral tooth, anterior petiolar face straight, posterior face convex and rounded, pettolar node blunt in profile. Erect hairs on most surfaces except legs and antennae, those on petiole and postpetiole especially coarse, with blunt tips decumbent pubescence on antennae and legs. Sculpture smooth and polished on dorsum of head, including most of clypeus, dorsum of mesosoma mostly smooth and shining, but with fine striolae, sides of pronotum with fine rugae, most of remainder of side of mesosoma with fine punctures, sides and tops of petiole and postpetiole with fine punctures, apex of node of petiole with poorly defined rugae, gaster smooth and polished.

Measurements (holotype shown in parentheses): HL (0.55)0.61, HW (0.41)-0.51, SL (0.43)-0.44, EL (0.13)-0.13, WL (0.55)-0.64, PW (0.11)-0.16, PL (0.16)-0.19, PPW (0.19)-0.25, PPL (0.14)-0.15. Indices: CI 75-84, SI 72-78, PI 69-84, PPI 136-167.

Queen
No Queens are known for this species.

Male
No Males are known for this species.

Type Material
TEXAS, Hudspeth Co., 25 KSW Van Horn, Indio Mountain Research Station, 7-vii-1991. W. Mackay #14518. Holotype worker

Etymology
Patronym. "Named in honor of Dr. John ("Jack") Bristol, professor emeritus of Biology and former Dean of the College of Sciences at the University of Texas at EI Paso"

References based on Global Ant Biodiversity Informatics

 * Fernandes, P.R. XXXX. Los hormigas del suelo en Mexico: Diversidad, distribucion e importancia (Hymenoptera: Formicidae).
 * Mackay W. P. 2000. A review of the New World ants of the subgenus Myrafant, (genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology 36: 265-444.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133