Temnothorax texanus

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Temnothorax texanus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Temnothorax
Species: T. texanus
Binomial name
Temnothorax texanus
(Wheeler, W.M., 1903)

Temnothorax-texanus-MCZ001L.jpg

Temnothorax-texanus-MCZ001D.jpg

Specimen Label

Synonyms

Nests in the ground with a preference for open or semi-open sites having sandy or clay soils (e.g., reported as being found in sand dunes, oak-rosemary xeric hummocks, turkey oak scrub) . The nest consists of a few chambers, 3 - 4 inches long, that are just a few inches below the surface. The nest entrance may be located at the base of a clump of grass. Workers will forage under litter or on exposed surfaces where they collect small insects and presumably any other food items they encounter. Monogynous. (Based on Wheeler 1905, Talbot 1934, Wesson and Wesson 1940, Smith 1952, Van Pelt 1958, Carter 1962, MacKay 2000)

Identification

In the Southeast this species and the larger Temnothorax pergandei are the only dark, shining Temnothorax found foraging on the ground in open areas. Some southeastern queens are blackish, others a striking brick red.

Mackay (2000) - A member of the Temnothorax tricarinatus species complex. This is a small (total length 2.25mm), dark brown species with a 12-segmented antenna, in which the postpetiole is more than 1.5 X the width of the petiole. The entire ant is roughly sculptured, with rugae on the head, top and side of the mesosoma, on the petiole and on the postpetiole. The gaster is smooth and glossy. The subpeduncular process is poorly defined and consists of a tiny tooth. The node of the petiole is truncate, the propodeum has well-developed spines.

Keys including this Species

Distribution

Central Florida west to Texas, north to New Jersey.

Distribution based on Regional Taxon Lists

Nearctic Region: United States (type locality).
Neotropical Region: Mexico.

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Habitat

Open sites with sandy or clay soils.

Abundance

Common.

Biology

Temnothorax-texanus.jpg

Regional Notes

Texas

All three sexual phases of this species were taken May 23, 1902, in nests consisting of a few small galleries, 3-4 inches long, excavated in the sand in rather damp spots under post-oaks and cedars. (Wheeler 1903)

Ohio

Several colonies of this species were found nesting in sandy soil under pine needles on the edge of dry, open sandstone bluffs in Jackson County. The workers ran about very rapidly in the sun over the pine needles. Winged phases were taken from a nest in early July. (Wesson and Wesson 1940)

Castes

Queen color can vary. Wheeler (1903) described the queen as "color of head, thorax and pedicel reddish-brown, darker on the dorsal surface. Gaster black." Deyrup and Cover (2004) reported "some southeastern queens are blackish, others a striking brick red."

Worker

Queen

Male

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • texanus. Leptothorax texanus Wheeler, W.M. 1903c: 245, pl. 12, fig. 16 (w.q.m.) U.S.A. Wheeler, G.C. & Wheeler, J. 1960b: 24 (l.). Combination in L. (Myrafant): Smith, M.R. 1950a: 30; in Temnothorax: Bolton, 2003: 272. Senior synonym of davisi: Deyrup & Cover, 2004a: 56. See also: Smith, M.R. 1952b: 102; Mackay, 2000: 415.
  • davisi. Leptothorax texanus subsp. davisi Wheeler, W.M. 1905f: 385 (w.q.) U.S.A. Combination in L. (Myrafant): Smith, D.R. 1979: 1395; in Temnothorax: Bolton, 2003: 271. Raised to species: Mackay, 2000: 340. Junior synonym of texanus: Deyrup & Cover, 2004a: 56. See also: Smith, M.R. 1952b: 104.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Length 2.25-2.75 mm. Head longer than broad. Eyes rather large. Mandibles 5-toothed. Clypeus moderately convex, its anterior border somewhat rounded. Antennae 12-jointed; scape reaching nearly to the posterior angle of the head; funiculus terminating in a very distinct 3-jointed club, the last joint of which is somewhat longer than the two preceding joints; first funicular joint nearly as long as joints 2-5; second funicular joint about as long as broad, the remaining joints broader than long. Thorax rather short, its humeral angles rounded, dorsum evenly and slightly rounded, without mesoepinotal constriction. Epinotal spines moderate, distinctly shorter than the declivous surface of the epinotum, scarcely as long as their distance apart at the base, rapidly tapering, acute, directed upward, outward and backward. their tips slightly deflected. Petiole from above fully 1 1/2 times as long as broad; its sides somewhat convex, so that its outline is subelliptical; in profile the anterior slope is abrupt and distinctly concave, the summit of the node flattened, and the posterior slope suddenly declivous; ventral tooth small, acute, directed downward. Postpetiole very large, fully twice as broad as the petiole; broader than long, its anterior and posterior angles rounded, so that it appears transversely elliptical from above; in profile it is very convex, especially in front. Gaster elliptical, depressed, without distinct anterior angles.

Mandibles coarsely striated. Clypeus traversed by several clean-cut longitudinal rugae, subsiding on the posterior portion which is smooth and shining. Head subopaque, coarsely reticulate-rugose; the rugae distinctly longitudinal only on the front and vertex; interrugal spaces secondarily reticulate. Neck evenly reticulate; thoracic dorsum very coarsely and irregularly reticulate-rugose; the, spaces between the rugae smooth and shining, because the secondary reticulation is indistinct or lacking. Pleurae somewhat more delicately and evenly rugose. Petiole and postpetiole coarsely reticulate-rugose, interrugal spaces filled with shallow foveolae or secondary reticulation. Gaster smooth and shining.

Hairs white, rather numerous and prominent; on the trunk clavate; shorter and more erect on the head and thorax"longer and slightly reclinate on the pedicel and gaster; on the legs and antennae distinct, non-clavate, more or less appressed.

Black or very dark-brown, especially on the head, thorax and petiole. Mandibles, excepting the teeth, funiculus, tips of epinotal spines, tarsi and articulations of legs, excepting the last tarsal joint, yellow; antennal scape brown.

Queen

Length 3.75-4 mm. Head more decidedly and extensively longitudinally rugose than in the worker. Neck delicately, pronotum more coarsely reticulate-rugose; mesonotum and paraptera traversed by numerous longitudinal rugae which are more or less interrupted and have a tendency to anastomose. Scutellum with such rugae only in front and on the sides, posteriorly it is nearly smooth and shining. Pleural and epinotum with rather coarse, distinctly longitudinal rugae. Epinotal spines small, acute, straight. Petiole with pointed node and more abruptly declivous posterior slope than in the worker, its dorsal surface scarcely flattened. Postpetiole very convex in front above. Sculpturing of petiole and postpetiole as in the worker.

Color of head, thorax and pedicel reddish-brown, darker on the dorsal surface. Gaster black. Pilosity of body and legs and color of the latter much as in the worker. Wings whitish-hyaline; veins and stigma yellow.

Male

Length 2-2.5 mm. Head exclusive of the mandibles broader than long, cheeks short, posterior angles convex and rounded. Mandibles overlapping each other. Antennae 13-jointed; scape as long as the first four joints of the funiculus, club very distinct, 4-jointed, the first, second and third subequal, fully 1 1/2 times as long as broad, apical joint as long as the second and third together; first funicular joint somewhat swollen, fully 1 1/2 times as long as broad; joints 2-8 longer than broad. Epinotum with two very small, indistinct protuberances in the place of the spines. Petiole slender, in profile concave below; anterior dorsal slope nearly straight, gradual, posterior slope shorter, abruptly declivous, rather concave. Postpetiole campanulate, about as long as broad; 1 1/2 times as broad as the petiole. Legs long and slender.

Mandibles striated. Clypeus coarsely and irregularly reticulate-rugose, shining. Head subopaque, evenly and rather delicately reticulate-rugose. Neck finely reticulate; mesonotum shining, with a faint reproduction of the irregular rugosity of the worker; remainder of thorax and the pedicel delicately reticulate-punctate. Gaster smooth and shining.

Hairs white, non-clavate, long and moderately abundant on the mandibles, pedicel and gaster; sparser elsewhere.

Black; mandibles and genitalia yellow; antennal funiculus grayish brown; wings like those of female; legs like those of the worker in color.

Type Material

Mackay (2000) - USA. Milano, Millan County, TX. American Museum of Natural History, Museum of Comparative Zoology [seen].

Etymology

Toponym. Types collected in Texas.

References

  • Carter, W. G. 1962. Ant distribution in North Carolina. Journal of the Elisha Mitchell Scientific Society. 78:150-204.
  • Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 272, Combination in Temnothorax)
  • Deyrup, M.; Cover, S. 2004b. A new species of the ant genus Leptothorax from Florida, with a key to the Leptothorax of the southeast (Hymenoptera: Formicidae). Fla. Entomol. 87(1): 51-59 (page 56, senior synonym of davisi)
  • MacKay, W. P. 2000. A review of the New World ants of the subgenus Myrafant, (genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology 36: 265-444 (page 415, see also)
  • Smith, M. R. 1952c. North American Leptothorax of the tricarinatus-texanus complex (Hymenoptera: Formicidae). J. N. Y. Entomol. Soc. 60: 96-106 (page 102, see also)
  • Talbot, M. 1934. Distribution of ant species in the Chicago region with reference to ecological factors and physiological toleration. Ecology. 15:416-439.
  • Van Pelt, A. F. 1958. The ecology of the ants of the Welaka Reserve, Florida (Hymenoptera: Formicidae). Part II. Annotated list. American Midland Naturalist. 59:1-57.
  • Wesson, L. G. and R. G. Wesson. 1940. A collection an ants from southcentral Ohio. American Midland Naturalist. 24:89-103
  • Wheeler, G. C.; Wheeler, J. 1960b. Supplementary studies on the larvae of the Myrmicinae (Hymenoptera: Formicidae). Proc. Entomol. Soc. Wash. 62: 1-32 (page 24, larva described)
  • Wheeler, W. M. 1903d. A revision of the North American ants of the genus Leptothorax Mayr. Proc. Acad. Nat. Sci. Phila. 55: 215-260 (page 245, pl. 12, fig. 16 worker, queen, male described)
  • Wheeler, W. M. 1905. An annotated list of the ants of New Jersey. Bulletin of the American Museum of Natural History. 21:371-403.