Temnothorax terrigena

Mackay (2000) "This species nests in and on the ground and under stones. It is reasonably common in Austin (Feener, 1981) and in the Chisos Mountains of southwestern TX in pinyons, desert canyons and high forests (Van Pelt, 1983)."

Identification
Mackay (2000) - A member of the Temnothorax andrei species complex. The workers of this species have a 12-segmented antenna, and are small (total length 1.5mm), yellow ants with black eyes. The maximum diameter of the eye is less than the distance from the anterior border of the eye to the anterior edge of the head near the insertion of the antennae. The propodeal spines are small and the node of the petiole is rounded. The subpeduncular process is small and weakly developed. The postpetiole is massive with the node being nearly twice as wide as the node of the petiole. The petiolar node is somewhat truncate in profile with the anterior and posterior faces being almost parallel. The entire dorsum of the head is densely and evenly punctate, the punctures lining up into poorly defined rows. The dorsum and side of the mesosoma, as well as the petiole and postpetiole, are densely and evenly punctate, similar to the sculpture of the head. The gaster is smooth and glossy.

This is an easily recognized species. Its light yellow color and very finely, but distinctly and completely punctate head separate it from most other species in the genus. The mesosoma is punctate in a similar manner, although the punctures are somewhat coarser. The heavily and densely punctate head would separate this species from most other species, including Temnothorax furunculus and Temnothorax andrei The relatively small eyes (maximum diameter about equal to distance between anterior margin of eye and base of mandible) would separate it from Temnothorax bestelmeyeri. This species can be distinguished from the similar Temnothorax andersoni by the smooth and glossy dorsum of the gaster.

Distribution
United States: Texas: Travis Co., Brewster Co., Cameron Co., Kinney Co.

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

Habitat
Known from high forests, oak woodland, coastal mesquite scrub, pinyon pine habitats and desert canyons.

Abundance
Common in some areas.

Biology
"This small species lives in and on the ground. At Austin I have occasionally seen a few workers running about on the dry gravelly hill-slopes exposed to the sun. At McNeil I took a few dozen workers and a dealated queen, which were inhabiting a small spherical chamber." (Wheeler 1903)

Nests in soil, under rocks and in cavities in objects on the ground.

Nomenclature

 *  terrigena. Leptothorax terrigena Wheeler, W.M. 1903c: 254, pl. 12, fig. 21 (w.q.) U.S.A. Combination in L. (Myrafant): Smith, D.R. 1979: 1395; in Temnothorax: Bolton, 2003: 272. See also: Mackay, 2000: 414.

Worker
Length 1.5-1.75 mm. Head rather narrow, with parallel sides. Mandibles 5-toothed. Clypeus moderately convex, without median impression and with broadly rounded, non-sinuate anterior border. Antennal 12-jointed, scape extending to j the distance between the eye and the posterior corner of the head; first funicular joint as long as the three succeeding joints together; joints 2-8 of funiculus decidedly broader than long, subequal; three terminal joints forming a distinct club, of which the two basal joints are subequal in length but not in thickness, arid together shorter than the terminal joint. Thorax slender, somewhat broader in front than behind, with rounded humeral angles and moderately elevated anterior pronotal border. Pleurae compressed; dorsum flattened and without mesoepinotal constrictions. Epinotal spines small, conical, distinctly longer and further apart than broad at their bases. Petiole short, hardly It times as long as broad, sides of node convex when seen from above and much broader than the peduncle; in profile the node is high and very thick with an evenly rounded summit, very steep and concave anterior, and very abrupt posterior declivity; ventral tooth rather large, blunt. Postpetiole twice as broad as the petiole, distinctly broader than long, transversely elliptical from above, with rounded anterior angles. Gaster of the usual shape.

Mandibles and clypeus subopaque, the former longitudinally striated and with a few coarse punctures, the latter longitudinally rugose. Head opaque throughout, evenly and densely punctate except along the sides of the frontal region, where there are a few delicate longitudinal rugae. Thorax, petiole and postpetiole opaque, densely punctate. Gaster smooth and shining.

Hairs white, moderately numerous, clavate on66 crown of head, thorax and abdomen; erect on head and thorax, more reclinate on the pedicel and gaster; minute, inconspicuous and appressed on the antennre and legs.

Whole body, even the anterior portion of the gaster, golden-yellow, except the antennal club which is blackened.

Queen
(dealated) Length 2.5 mm. Head opaque, densely punctate; cheeks and whole preocellar region irregularly longitudinally rugulose, the postocellar region and posterior angles more reticulate. Thorax opaque, densely punctate; mesonotum and scutellum with very faint, parallel, longitudinal rugae. Epinotal spines very short and stout, regularly conical, not as far apart as they are broad at the base. Petiole and postpetiole like those of the worker, but the latter segment fully twice as broad as long. Both segments of the pedicel densely punctate, opaque, except the dorsal surfaces of the nodes which are somewhat smooth and shining. Body brownish yellow, legs pale-yellow. Antennal club, wing-insertions, sides and posterior border of first gastric segment, a broad transverse band on the second gastric segment and the tip of the gaster, dark-brown. Pilosity like that of the worker.

Type Material
Mackay (2000) - USA. Austin and McNeil (Travis county), Tex., [seen].

References based on Global Ant Biodiversity Informatics

 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Hernandez, F. Varela and G. Castano-Meneses. 2010. Checklist, Biological Notes and Distribution of Ants (Hymenoptera: Formicidae) from Barranca de Metztitlán Biosphere Reserve, Hidalgo, Mexico. Sociobiology 56(2):397-434
 * Mackay W. P. 2000. A review of the New World ants of the subgenus Myrafant, (genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology 36: 265-444.
 * O'Keefe S. T., J. L. Cook, T. Dudek, D. F. Wunneburger, M. D. Guzman, R. N. Coulson, and S. B. Vinson. 2000. The Distribution of Texas Ants. The Southwestern Entomologist 22: 1-92.
 * Smith M. R. 1936. A list of the ants of Texas. Journal of the New York Entomological Society 44: 155-170.
 * Van Pelt, A. 1983. Ants of the Chisos Mountains, Texas (Hymenoptera: Formicidae) . Southwestern Naturalist 28:137-142.
 * Varela-Hernandez, F., M. Rocha-Ortega, W. P. MacKay, and R. W. Jones. 2016. Lista preliminar de las hormigas (Hymenoptera: Formicidae) del estado de Queretaro, Mexico. Pages 429-435 in . W. Jones., and V. Serrano-Cardenas, editors. Historia Natural de Queretaro. Universidad Autonoma de Queretaro, Mexico.
 * Vasquez-Bolanos M. 2011. Checklist of the ants (Hymenoptera: Formicidae) from Mexico. Dugesiana 18(1): 95-133.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Wheeler W. M. 1903. A revision of the North American ants of the genus Leptothorax Mayr. Proceedings of the Academy of Natural Sciences of Philadelphia. 55: 215-260.
 * Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.