Temnothorax carinatus

.infobox img {border:1px solid #AAAAAA;}

Based on Mackay (2000): "This species nests beneath stones, with worker number per colony ranging between 29-182 workers (Cole, 1958b). Nests are monogynous. Temnothorax carinatus occurs in habitats ranging from desert grasslands, to juniper forests with cholla to desert riparian sites up to pine forests. Sexuals have been found in nests from June to August."

Identification
Mackay (2000) "Diagnosis: This is a yellow brown species with a 12-segmented antenna. The dorsum of the head is usually finely striolate. but is still moderately shining. The top and side of the mesosoma are mostly punctate, although there may be fme rugulae along the lower border of the pronotum. The propodeal armature consists of small angles. The petiolar node is blunt and both the petiole and postpetiole are punctate. without any sign of rugulae or costulae. The subpetiolar process is well developed. The postpetiole is at least 1.5 X as wide as the greatest width of the petiole. The gaster is completely smooth and shining.

This species superficially resembles Temnothorax andrei, but can be easily distinguished by a number of characters (Cole. 1958a). The postpetiole is 1.5-1.65 X the width of the petiole, whereas in Temnothorax andrei it is about 1.2 times the width of the petiole. In addition the node of the petiole in profile has anterior and posterior faces which are almost parallel. whereas the faces of the node of Temnothorax andrei converge towards the apex. This species is a member of the tricarinatus species complex and could be confused with Temnothorax tricarinatus or Temnothorax neomexicanus, but differs most obviously in being lighter in color. The sides of the petiole and postpetiole are punctate (rugose or rugulose in Temnothorax tricarinatus and Temnothorax neomexicanus). It is much lighter in color than either of these 2 species and the propodeal spines are poorly developed, as compared to the latter 2 species. It can be separated from Temnothorax rugulosus as the hairs on the scape are nearly all closely placed on the surface, those of [[Temnothorax rugulosus[[ are partially raised, nearly suberect. The dorsum of the mesosoma is mostly punctate, whereas the sculpture of the top of the mesosoma of Temnothorax rugulosus has fine rugulae. It is similar to Temnothorax neomexicanus, but differs in being yellow or orange (Temnothorax neomexicanus is dark or black), the propodeal spines are usually poorly developed, consisting of tiny angles (small, but well developed spines in Temnothorax neomexicanus) and the subpeduncular process consists of an elongate lobe (tiny tooth in Temnothorax neomexicanus). Temnothorax carinatus has fine striolae on the dorsum of the head, and has a well-developed subpeduncular tooth, and seems to occur in more mesic sites. Temnothorax neomexicanus has at least part of the dorsum of the head finely punctate, the subpeduncular process is poorly developed, and is generally found in more arid sites."

Distribution
This taxon was described from the United States.

USA: Wyoming, Nevada, New Mexico, southeastern Arizona, western Texas. MEXICO: Chihuahua.

Habitat
This species has been found in habitats that range from desert grasslands, to juniper forests with cholla, to desert riparian sites and up through elevations reaching into pine forests.

Abundance
Temnothorax carinatus is known to be common in the Chisos Mountains (Van Pelt 1983).

Worker
Holotype worker. Head length, 0.68 mm.; head width behind eyes, 0.65 mm.; scape length, 0.51 mm.; thoracic length, 0.82 mm.; pronotal width, 0.39 mm.; petiolar length, 0.27 mm.; postpetiolar length, 0.15 mm.; petiolar node length, 0.08 mm.; petiolar node width, 0.14 mm.; postpetiolar node length, 0.13 mm.; postpetiolar node width, 0.29 mm.; length of gaster, 0.90 mm.; total body length, 2.82 mm.

Head longer than broad, sides subparallel, occipital border faintly concave mesally, occipital corners broadly rounded; frontal lobes extending anteriolaterally, the outer margin evenly and very broadly convex; median lobe of clypeus only moderately convex; frontal triangle distinct, faintly impressed, longer than wide; antennae 12-segmented, scape rather robust, basal segment of funiculus about as long as the succeeding three segments taken together, scapes in repose extending nearly to posterior border of head. Thorax, in profile, posteriorly as far as base of epinotum, very broadly convex, the outline unbroken by impressions; pronotal dorsum meeting anterior declivity at a pronounced sharp angle; mesoepinotal suture absent; base of epinotum descending evenly and gradually from mesonotum, declivity of epinotum steep; epinotal armature consisting of a pair of short, rather blunt teeth, broad at base. Viewed from above, with pronotum broad, narrowing posteriorly, the humeri poorly developed; the sides rather sharply narrowed and impressed at beginning of epinotum; sides of meso-epinotal area subparallel. Viewed in profile, petiolar node strongly developed, the anterior declivity long, faintly concave, rather steep, and meeting apex of node in a much rounded angle; posterior declivity short, straight, steep, meeting apex of node in a rounded angle; apex of node broadly convex anteriorly, less so posteriorly, higher in front than behind; anterior peduncle short, venter bearing a well-developed, broad, blunt, downwardly-directed spine; node of postpetiole robust, apex broadly and evenly rounded, anterior surface convex, rather steep, posterior declivity gradual and very faintly convex. Viewed from above, petiolar node broader than long, sharply subrectangular; postpetiolar node massive, much broader than long, slightly more than twice as broad as petiolar node, anterior corners broadly convex, a little wider in front than behind, subrectangular. Femora and tibiae incrassated.

Gaster broadly elliptical; truncate at base, the corners acute.

Head rather smooth and shining, the surface smoothness interrupted by sparse, small, shallow, faint punctures and by numerous fine striae which are longitudinal mesally but which form semicircular whorls on and anterior to the occipital corners; striae somewhat more pronounced on genae. Entire thorax (except for pronotal collar), petiole, and postpetiole subopaque, finely and very densely punctulate; pronotal collar shining, finely and transversely striolate; extending across anterior pronotal declivity to the pronotal collar are several transverse rugulae, the upper ones tending to form a definite pronotal carinula; sides of prothorax longitudinally striate; legs and antennae smooth and shining. Gaster smooth and highly shining.

Hairs quite sparse, mostly rather short, stout, blunt, silvery, and largely erect; on dorsum of head sparse, short, scattered; on venter of head short, fine, pointed, subappressed; longer and more delicate on clypeus. Hairs on thorax longer, stouter, blunt, clavate and subclavate, sparse, scattered, erect, absent from lateral surfaces and from epinotal base and declivity; one hair on each epinotal "spine"; absent from venter of petiole and postpetiole and from anterior declivity of petiolar node; longer on petiolar and postpetiolar nodes. Hairs very short, slender, sparse, suberect and appressed on legs. Hairs on gastric dorsum shorter, more numerous, and somewhat more slender and less blunt than on thorax; on venter sparse, short, delicate, appressed and subappressed.

Dorsum of head bears sparse, scattered, short, suberect and subappressed hairs which might be considered to represent a pubescence.

Color a uniform, rich, light tan; distal half of gastric dorsum infuscated.

Queen
Paratype nest queen. Head length, 0.73 mm.; head width behind eyes, 0.6.5 mm.; head width in front of eyes, 0.56 mm.; scape length, 0.61 mm.; thoracic length, 1.19 mm.; petiolar length, 0.32; postpetiolar length, 0.20 mm.; length of petiolar node, 0.07 mm.; width of petiolar node, 0.17 mm.; greatest thoracic width, 0.73 mm.; length of postpetiolar node, 0.17 mm.; width of postpetiolar node, 0.37 mm.; length of gaster, 2.06 mm.; total body length, 4.50 mm.

Differing from the holotype largely in the following characteristics, except for the normal sexual traits: Cephalic striae stronger and more dense, except for a central strip between frontal triangle and median ocellus which is relatively free of sculpture as are also the posterior corners and the occipital margin. Thorax mostly without punctures, the sides longitudinally rugulose; scutum smooth and shining with only a very few scattered, longitudinal striae; lateral portions of scutellum densely and longitudinally striate; epinotal base and declivity transversely and densely striatopunctate; sides of epinotum longitudinally striatopunctate; posterior declivities of petiolar and post petiolar nodes transversely rugulose; anterior declivity of petiolar node transversely stiatopunctate; apex and anterior declivity of postpetiolar node smooth and shining, the sides obliquely striate; viewed from above, postpetiolar node shaped like a posteriorly-directed truncated cone, the anterior margin very broadly convex. In profile, petiolar node more attenuated apically than in holotype, the apical dorsum nearly flat; anterior declivity of petiole transversely striolate. Epinotum with a pair of definite spines which are rather short, broad, and blunt. Hairs shorter and somewhat more abundant than those of holotype, clavate and non-clavate on thoracic dorsum; eyes with sparse, scattered, very short, erect hairs. The color is notably darker than that of holotype, the entire body except the mandibles and appendages being a uniform medium brown; mandibles and appendages a light tan. Pubescence present but very sparse, appressed, and limited to head and gaster.

Male
No Males known for this species.

Type Material
The holotype, a series of paratypic workers from each colony, and the queen are in the writer's collection. Series of paratypic workers will be deposited in the U.S. National Museum, the Museum of Comparative Zoology (Harvard), and the American Museum of Natural History, and in the collections of W. S. Creighton and R. L. Gregg.

Type Locality Information
Three nests (TX-43, TX-55, and TX-56) were found beneath stones at an elevation of 5,400 ft. in Limpia Canyon, Davis Mts., Texas, on June 11, 1956.

Etymology
Morphological.

Additional References
Bestelmeyer, B. T. 2005. Does desertification diminish biodiversity? Enhancement of ant diversity by shrub invasion in South-western USA. Diversity and Distributions. 11:45-55.


 * [[Media:Cole 1957d.pdf|Cole, A. C., Jr. 1957d. Another new Leptothorax from Texas (Hymenoptera: Formicidae). J. Tenn. Acad. Sci. 32: 213-215 PDF]]

Cole, A. C., Jr. 1958. North American Leptothorax of the nitens-carinatus complex (Hymenoptera: Formicidae). Annals of the Entomological Society of America. 51:535-538.

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

Van Pelt, A. F. 1983. Ants of the Chisos Mountains, Texas (Hymenoptera: Formicidae). Southwestern Naturalist. 28:137-142.

Wheeler, G. C. and J. Wheeler. 1988. A checklist of the ants of Wyoming (Hymenoptera: Formicidae). Insecta Mundi. 2:231-239.