Camponotus texanus

Camponotus texanus usually nests in dead limbs (on living trees) and in logs of oaks. Wheeler (1903) noted that his three nests were collected from oak logs. A fourth nest was found in a crevice between two huge rocks. They also occasionally nest under stones on rocky slopes. These ants are very active and difficult to capture and are restricted to Texas, United States. (Mackay, 2019)

Compare with Camponotus bellacolor, Camponotus laevissimus, Camponotus schaefferi.

The majors and minors of C. texanus generally have a black head and gaster, with reddish or at least light brown mesosoma and legs. The medial anterior clypeal border is concave in both the major worker and the female between two lateral angles. Erect hairs on the scape are lacking in the major and minor workers, in addition to the female. The anteclypeus of the minor worker generally lacks the concave area, or it is poorly developed.

The female is a similar color, except darker. The clypeal teeth on the anterior margin of the clypeus are well developed. The entire ant is primarily glossy and shiny.

Males are relatively large, bicolored specimens (black head and gaster, red mesosoma).

Comparisons
The protuberances or teeth on the anterior border of the clypeus of C. texanus will separate the major and female of this species from most others in the subgenus, except Camponotus schaefferi (AZ, NM) and Camponotus bellacolor (NE Mexico). Camponotus texanus can be separated from C. schaefferi as at least the head and gaster are darker in color, whereas C. schaefferi is completely yellowish red. These are the only three species of New World ants of the subgenus Camponotus that have the strongly concave medial anterior border of the clypeus with lateral angles. Camponotus texanus major workers could be confused with the bicolored C. bellacolor (NE Mexico). The distributions would separate them. Additionally, the dorsum of the gaster of C. texanus is only slightly sculptured and strongly shining, the dorsum of the gaster of C. bellacolor is covered with very fine transverse striae, and the surface is dull, with only the posterior border of each tergum slightly shining (see below for another hint).

The glossy and shiny surface and the form of the anterior clypeal border will separate C. texanus from all of the other species which are occasionally bicolored, such as Camponotus americanus (E US), C. bellacolor (NE Mexico), Camponotus chromaiodes (E US), Camponotus herculeanus (S Canada, US) and Camponotus johnsoni (Baja California).

The shiny black Camponotus laevissimus (southeastern Canada, western USA and northwestern to central Mexico) would be easily separated, as C. laevissimus does not have 2 angles along the anterior margin of the clypeus, and most surface are smooth and strongly shining.

Camponotus texanus is found in arid habitats with scattered oaks, grassy areas with oaks, live oak forests, juniper (Juniperus ashei) forests and hackberry forests.

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

Biology
Brood were found in nests in August.

It was the most frequent ant in arboreal pitfall traps at Brackenridge Field Lab of the University of Texas, Austin Texas in plots without the red imported fire ant, Solenopsis invicta (as S. wagneri, Kaspari, 2000).

It has been found in caves (Cokendolpher et al., 2009).

Nomenclature

 *  texanus. Camponotus texanus Wheeler, W.M. 1903b: 108, fig. 10 (s.w.q.m.) U.S.A. Combination in C. (Myrmentoma): Emery, 1920b: 257; in C. (Camponotus): Forel, 1914a: 266; Creighton, 1950a: 371.

Description
Major worker measurements (mm): HL 2.94 - 2.96, HW 2.86 - 2.90, SL 2.34 - 2.42, EL 0.65, CL 0.96 - 1.00, CW 0.96 - 1.00, WL 3.82 - 3.86, FFL 2.16 - 2.18, FFW 0.76. Indices: CI 97 - 98, SI 80 - 82, CLI 99 - 100, FFI 35.

Mandible with 5 teeth; anterior border of clypeus concave, strongly depressed in middle, with 2 well-developed angulate lateral processes; head narrowed anteriorly in area of cheeks, sides nearly straight, posterior margin concave; eyes failing to reach sides of head by about ½ minimum diameter; scape extending about 1 funicular segment past posterior lateral corner of head; propodeum rounded between faces, dorsopropodeum about twice length of posteropropodeum, posteropropodeum concave; spiracle elongate; petiole narrow in profile, anterior and posterior faces nearly parallel, node convex and rounded as seen from front.

Erect and suberect setae sparse, setae on clypeus nearly restricted to margins, especially along anterior margin; cheeks, sides of head, posterior lateral corners, scapes without erect and suberect setae (except apex, few tiny setae may be on shaft), few setae on frontal carinae, extending to posterior margin, several erect and suberect setae on ventral surface of head, few setae on dorsum of mesosoma, on petiole and on dorsal surface of gaster; appressed pubescence very sparse, few tiny setae on head and on dorsum of gaster.

Most surfaces smooth and shiny, head finely coriaceous, with few scattered punctures, mesosoma coriaceous, but glossy and shining, gaster finely coriaceous and shining.

Usually bicolored, with head and gaster black, mesosoma and legs red or reddish brown.

Minor worker measurements (mm): HL 1.92 - 2.14, HW 1.52 - 1.66, SL 2.18 - 2.35, EL 0.53 - 0.55, CL 0.60 - 0.65, CW 0.84 - 0.85, WL 3.06 - 3.16, FFL 1.86 - 1.94, FFW 0.61 - 0.65. Indices: CI 78 - 79, SI 110 - 114, CLI 131 - 140, FFI 33 - 34.

Similar to major worker, except lateral protuberances on anterior border of clypeus are poorly developed, sides of head slightly convex, posterior margin of head slightly concave to convex, eyes reach sides of head, scape extends about ½ length past posterior lateral corners of head. Pilosity, sculpture and color as in major worker.

Female measurements (mm): HL 2.76 - 2.96, HW 2.52 - 2.72, SL 2.42 - 2.46, EL 0.71 - 0.75, CL 0.91 - 0.94, CW 1.05 - 1.06, WL 4.32 - 4.56, FFL 2.28 - 2.34, FFW 0.70 - 0.73. Indices: CI 91 - 92, SI 82 - 89, CLI 113 - 115, FFI 31.

Similar to major worker, protuberances on anterior border of clypeus well developed, area between them depressed; sides of head nearly straight, posterior margin nearly straight; eyes nearly reach sides of head; scapes extend 2 funicular segments past posterior lateral corner of head; propodeum rounded in profile, dorsopropodeum shorter than weakly concave posteropropodeum, spiracle elongate; petiole narrow in profile, node weakly concave, or straight as seen from front.

Erect and suberect setae of female similar to those of major worker, appressed setae sparse, sculpture as in major worker, color similar to major worker, except mesosoma usually dark brown.

References based on Global Ant Biodiversity Informatics

 * Cokendolpher J. C., and O. F. Francke. 1990. The ants (Hymenoptera, Formicidae) of western Texas. Part II. Subfamilies Ecitoninae, Ponerinae, Pseudomyrmecinae, Dolichoderinae, and Formicinae. Special Publications, the Museum. Texas Tech University 30:1-76.
 * Cokendolpher J.C., Reddell J.R., Taylor S.J, Krejca J.K., Suarez A.V. and Pekins C.E. 2009. Further ants (Hymenoptera: Formicidae) from caves of Texas [Hormigas (Hymenoptera: Formicdae) adicionales de cuevas de Texas]. Texas Memorial Museum Speleological Monographs, 7. Studies on the cave and endogean fauna of North America, V. Pp. 151-168
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Longino, J.T. 2010. Personal Communication. Longino Collection Database
 * Morrison, L.W. 2002. Long-Term Impacts of an Arthropod-Community Invasion by the Imported Fire Ant, Solenopsis invicta. Ecology 83(8):2337-2345
 * 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.
 * Reddell J. R., and J. C. Cokendolpher. 2001. Ants (Hymenoptera: Formicidae) from caves of Belize, Mexico, and California and Texas (U.S.A.) Texas. Texas Memorial Museum Speleological Monographs 5: 129-154.
 * 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.
 * Wheeler W. M. 1903. A decad of Texan Formicidae. Psyche (Cambridge). 10: 93-111.
 * Wheeler W. M. 1910. The North American ants of the genus Camponotus Mayr. Annals of the New York Academy of Sciences 20: 295-354.
 * Wheeler W. M. 1917. The mountain ants of western North America. Proceedings of the American Academy of Arts and Sciences 52: 457-569.
 * Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.