Temnothorax nevadensis

Mackay (2000) "This species nests in soil (Wheeler, 1903a; Wheeler and Wheeler, 1973a, 1986) in moist areas (Cole, 1934), usually under stones (Wheeler, 1903a; Cole, 1942; Wheeler and Wheeler, 1986), or in rotten wood. It may be involved in plesiobiosis, as Wheeler (l903a) reported it nesting at the entrance of a Trachymyrmex turrifex nest and at the edge of a flourishing colony of Pheidole tepicana (= P. instabilis). Insecticide treatments for the spruce budworm in eastern Oregon had little impact on this species (Murphy and Croft. 1990)."



Identification
Modified from Mackay (2000) ''This species is fairly common throughout the western United States. The clypeus has a moderately well defined medial carina and 2 well-defined lateral carina, which curve and cross the anterior part of the medial lobe of the clypeus. It has a completely and strongly striated head with punctures between the striae, and with rarely a slender median strip without sculpture. The sides of the pronotum are distinctly and coarsely rugose, with the background weakly punctate, but shining. The dorsum of the mesonotum is striate to finely rugose, but mixed with background punctures and not as shiny as the background of the sides of the pronotum. The petiole and postpetiole are primarily punctate, but fine rugulae can be seen on the dorsum of the petiole. There is usually a single ruga on the side of the petiole. Some larger specimens have several poorly defined rugae on the side of the petiole (making it look "wrinkled"), and occasionally on the anterior face. These larger specimens usually have longer propodeal spines, sometimes as long as the distance between the bases. These specimens were referred to as L. nevadensis subsp. melanderi in the past.

Leptothorax nevadensis and L. neomexicanus'' have similar lateral clypeal carinae, which usually curve and connect on the anterior part of the medial lobe of the clypeus. They are thus apparently closely related. They can be easily separated as the dorsum of the head of L. nevadensis is nearly completely sculptured, whereas part of the head of L. neomexicanus is smooth and shining.

Range
USA. Western states including Washington, Idaho, Montana, Wyoming, California, Nevada, Colorado and Utah.

Habitat
Wheeler and Wheeler (1986) "Known from cool desert, pinyon-juniper forest (Cole, 1966), coniferous forest (Wheeler and Wheeler, 1973a) and alpine areas."

Mackay (2000) "D. S. Chandler (pers. comm.) collected this species in litter in a number of plant communities, including tanbark oak, oak leaf litter near a spring, maple and oak litter, Douglas fir, and laurel.

Abundance
Commmon.

Biology
Ward 2005: 936 NEEDS EDITING Comments. This is another common species of Temnothorax in California and other western states, occupying a broad range of habitats, including coastal scrub, chaparral, oak woodland, open coniferous forest, and sagebrush desert. The worker can be recognized by the dark brown to black body color; relatively long and slender pilosity; opaque to sublucid head, with longitudinal rugoreticulate sculpture and scattered foveolae; dense foveolate sculpture on the mesosoma, overlain by weak rugulae; well developed propodeal spines; slender petiole, with anterior face rounding abruptly into posterodorsal face (Fig. 9); and relatively narrow postpetiole (PPW/DPW 1.34–1.51, PPW/T4W 0.33–0.39; n = 6). Size is variable, such that worker HW 0.47–0.70, but usually >0.55. There is considerable variation in the length and slenderness of the propodeal spines but they are always longer than the anteroventral petiolar process. In some T. nevadensis workers from eastern California and Nevada the head is rather shiny (sculpture much reduced), but the variation appears to be continuous. Interestingly, a similar trend is seen in the related arboreal species, T. gallae (M. R. Smith): near its eastern limit (in Joshua Tree National Park, southeastern California) workers have shinier heads than in populations farther west. Taking into account the variability inherent in T. nevadensis, this species readily encompasses the forms described by Mackay (2000) as T. lindae and T. maryanae (and placed inexplicably by him in different species complexes, separate from one another and from T. nevadensis), plus two of the three taxa previously considered to be subspecies of T. nevadensis: melanderi and eldoradensis. I have not examined the type of T. melanderi so some doubt remains here, but the original description and the type locality suggest that the synonymy is justified. On the other hand, T. rudis, described as a subspecies of T. nevadensis—and synonymized under T. nevadensis by Mackay (2000)—is a distinct and easily recognized species, as documented below.

Original Combination
Leptothorax nevadensis Wheeler, W.M. 1903c: 252, pl. 12, fig. 20 (w.q.m.) U.S.A. Wheeler, G.C. & Wheeler, J. 1973b: 71 (l.). Combination in L. (Myrafant): Smith, D.R. 1979: 1393; in Temnothorax: Bolton, 2003: 271. Senior synonym of eldoradensis, melanderi: MacKay, 2000: 376; of lindae, maryanae: Ward, 2005: 16

Worker
Length 2.5-3 mm. Mandibles 5-toothed. Clypeus depressed in the middle, its anterior margin sinuately excised. Antennae 12-jointed, scape reaching to posterior corner of the head, first funicular joint as long as joints 2-4 together, joints 2-6 slightly broader than long, joints 7 and 8 as long as broad; two basal joints of club subequal, together shorter than the terminal joint. Thorax above in front of about the same width as below and behind; humeri much rounded, dorsum flattened in profile,without mesoepinotal constriction. Epinotal spines robust, pointed, decidedly longer than broad at their bases, and nearer together at their bases than long, directed upward, outward and backward. Petiole 1 1/2 times as long as broad, sides of node rounded, broader than the peduncle; .seen from above the node is transverse, in profile it is narrow antero-posteriorly, its anterior slope gently ascending, concave, its posterior slope more abrupt, also concave, summit rounded; ventral surface of petiole with a prominent, compressed, downwardly directed tooth. Postpetiole in profile with a prominent, sometimes slightly angular node; the segment seen from above is transversely elliptical, about half again as broad as long, its anterior angles rounded. Gaster and legs of the usual conformation.

Mandibles striate and punctate. Clypeus subopaque, its surface, especially at the sides, traversed by rather coarse longitudinal rugaae. Head with a satiny luster, sparsely punctate and with delicate longitudinal rugalae which become decidedly reticulate in the antennal foveae. Thorax subopaque, its dorsal surface irregularly reticulate-rugose and foveolate, pleurae, petiole and postpetiole regularly foveolate-punctate; posterior epinotal declivity rather coarsely longitudinally rugose. Gaster smooth and shining.

Hairs yellow, not very abundant; clavate on thorax, pedicel and crown of head; short and erect on head and thorax, longer and somewhat reclinate on the pedicel and gaster. Hairs on antennae, legs and sides of head less conspicuous and appressed, except on the antennae, where they are suberect.

Rather dark reddish-brown, ventral portions of head, thorax and pedicel and the incisures of the gastric segments, yellowish. Legs and antennae yellowish, middle of femora and the antennal club darkbrown. Immature specimens have the thorax and pedicel more extensively yellow.

Queen
Length 4.5 mm. Mandibles densely striated and somewhat punctate. Clypeus with coarse longitudinal rugae, one of which forms a distinct carina in the middle of the sclerite. Frontal area opaque. Head with coarse and very regular longitudinal rugae, but little diverging behind and but slightly reticulate. On the upper surface of the head there are also a number of shallow but distinct foveolae in the interrugal furrows. Pronotum and pleurae coarsely longitudinally rugose; mesonotum shining, sparsely foveolate and rather indistinctly longitudinally rugose, especially in front. Scutellum and paraptera like the mesonotum, the former with indications of rugae only at its anterior border. Whole epinotum subopaque, coarsely rugose, even over the entire surface of the robust, pointed spines, which are as long as they are broad at their bases. Declivous surface of epinotum regularly transversely rugose. Petiole and postpetiole opaque, reticulate .and punctate-rugose, more coarsely on the sides than on the summits of the nodes; petiolar node in profile more acute than in the worker. Gaster very glabrous. Head, thorax and pedicel rich reddish-brown; gaster decidedly darker. Legs and antennre yellow. In the latter all the joints of the funiculus are distinctly longer than broad, and the club, which is not infuscated, is indistinct. Wing-insertions black, Hairs on the body sparse, yellow, not clavate like those of the worker, but more or less tapering.

Male
Length 2.5-3 mm. Mandibles dentate, overlapping with their blades. Clypeus convex, truncated in the middle in front. Antennae 13-jointed; scape slender, as long as joints 1-5 of the funiculus. First funicular joint fully twice as long as broad, much stouter than the succeeding joints, except those of the 4-jointed club; joints 3-7 longer than broad; three basal joints of club subequal, each not more than half as long as the terminal joint. Cheeks short. Thorax with very deep Mayrian and other sutures. Epinotum without indications of spines. Petiole and postpetiole longer and with lower. nodes than in the worker. Gaster of the usual shape.

Mandibles and clypeus somewhat shining, the latter with a few prominent and irregular longitudinal rugal. Head decidedly opaque, uniformly and densely punctate. Thorax shining, mesonotum, scutellum and pleural with faint, parallel, longitudinal striae. Pronotum and epinotum more reticulate-rugose. Petiole and postpetiole smooth and shining on the summits of the nodes, elsewhere subopaque, finely reticulate-rugose. Gaster smooth and shining.

Hairs covering the body sparse, whitish, non-clavate, longest and most conspicuous on the gaster, very small and appressed on the legs and antennal.

Black, thorax and pedicel more piceous, especially on their lateral and ventral surfaces. The following parts are yellowish, or yellow suffused with piceous: mandibles, except their teeth, which are black, antennae, legs and genitalia. Wings whitish-hyaline, veins and stigma colorless.

Type Material
As reported in Mackay (2000) "Type series: AMNH.MCZC [seen]."

Type Locality
USA. King's Canyon, Ormsby county, NV.