Temnothorax andersoni

The only biological information known for this species is that workers have been found in mixed hardwoods leaf-litter samples in Big Bend National Park, Texas.

Identification
Mackay (2000) - A member of the Temnothorax andersoni species complex. This is a small, concolorous yellow brown species with a 12-segmented antenna. The entire head and mesosoma are coarsely and densely punctate. The propodeal spines are well developed, but small. The petiolar node is blunt in profile. The gaster has punctures on the basal third of first gastral tergum.

This species is easily recognized by the punctures on the first gastral tergum. It can be separated from other species with a sculptured gaster, such as Temnothorax obliquicanthus, Temnothorax silvestrii and Temnothorax rugosus, by the small propodeal spines. Temnothorax rugosus and Temnothorax silvestrii have coarse rugae on the dorsum of the mesosoma, Temnothorax andersoni is densely punctate in this region, without any evidence of rugae. Temnothorax obliquicanthus has kidney shaped eyes, Temnothorax andersoni has round eyes. There is no chance of confusing this species with Temnothorax hispidus, as the outline of the mesosoma is continuous, without the depressed mesopropodeal suture found in Temnothorax hispidus. If the sculpture on the dorsum of the gaster is too fine to be noticed, Temnothorax andersoni would key with difficulty to Temnothorax terrigena. It could be separated from the latter species as the node of the petiole is obliquely truncate,whereas the node of the petiole of Temnothorax terrigena is broadly rounded. Additionally, close inspection of the gaster should reveal the fine sculpture.

This species could be confused with other pale species found in the Chihuahuan Desert, including Temnothorax bestelmeyeri, Temnothorax cokendolpheri, Temnothorax coleenae, and Temnothorax liebi.

Distribution
Known only from Big Bend National Park, Texas.

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

Habitat
The only collections of Temnothorax andersoni are from mixed hardwood forest leaf-litter.

Abundance
Only known from type material.

Nomenclature

 *  andersoni. Leptothorax (Myrafant) andersoni Mackay, W.P., 2000: 314, figs. 14, 83 (w.) U.S.A. Combination in Temnothorax: Bolton, 2003: 271.

Worker
Mandibles with 5 teeth, only apical 3 well defined; anterior border of clypeus convex, clypeus with well formed median carina plus several lateral carinae; sides of head broadly and weakly convex; vertex weakly concave; eyes small, 8 or 9 facets in greatest diameter; antennae with 12 segments; mesosoma without any sutures breaking surface; propodeal spines small, but well developed and acute; petiole with well developed subpeduncular tooth, acute and with flange which extends posteriorly at least half length of petiole, anterior petiolar face, concave posterior face convex, petiolar node blunt in profile.

Erect hairs on all surfaces, except legs and antennae, up to 0.8mm in length; decumbent pubescence sparse, present on legs and antennae.

Sculpture consisting of closely set, dense punctures on all surfaces of head (except middle of underside of head), mesosoma, petiole and postpetiole, and gaster with punctures over basal third of first gastral tergum.

Color: light yellowish brown.

Measurement: HL 0.55-0.64, HW 0.46-0.52, SL 0.430.47, EL 0.13-0.14, WL 0.64-0.68, PW 0.14-0.16, PL 0.18-0.19, PPW 0.22-0.23, PPL 0.16-0.17. Indices: CI 81-84, SI 73-78, PI 78-84, PPI 130-135.

Queen
No known Queens for this species.

Male
No known Males for this species.

Type Material
USA. Texas, Brewster Co., Big Bend National Park, Cattail Falls, 6-ix-1988, R. Anderson. Holotype worker and two paratype workers.

Etymology
Patronym. "Named in honor of the collector, Robert Anderson, who has provided me with abundant material collected from litter."

References based on Global Ant Biodiversity Informatics

 * Mackay W. P. 2000. A review of the New World ants of the subgenus Myrafant, (genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology 36: 265-444.