Temnothorax schmittii

Only known from types.

Identification
Mackay (2000) - A member of the Temnothorax tricarinatus species complex. The workers of this species have 12-segmented antennae; the clypeus has a well developed, medial, longitudinal carina extending nearly full length; the humeral angles are sharp and prominent, with a carina which extends posteriorly, forming a transverse ridge across the pronotum, giving the pronotum a square-shouldered appearance; the mesosoma is without a constriction at the mesopropodeal suture; the propodeal spines are well formed, longer than width at bases, tapering and pointed, directed distinctly backward though slightly pointed upward and outward, ventral outline of spine is distinctly concave, dorsum convex; petiolar node narrow in profile, subpeduncular process well developed. The head is very smooth and shining, sides of frontal area, cheeks and subocular region subopaque and delicately and longitudinally rugose. The pronotum and mesonotum are very smooth and shining, the pleurae with delicate longitudinal rugae which are coarser on side of propodeum. Erect hairs are white, moderately abundant, clavate. These ants are dark brown, almost black, with the mandibles, neck, funiculus and legs yellow.

This is a very unusual species due to the smoothness of the head and mesosoma, and the angulate corners of the pronotum. The types are light brown in color, but it is also black with white hairs and yellow legs (Gregg. 1963). It would not be confused with any other known North American species, except possibly Temnothorax nitens, which has legs with the same shade of light brown as the mesosoma. It can be easily separated, as the propodeal spines of Temnothorax nitens are poorly developed.

Distribution
United States: Colorado.

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

Abundance
Only known from the type collection.

Nomenclature

 *  schmittii. Leptothorax schmittii Wheeler, W.M. 1903c: 242, pl. 12, fig. 14 (w.) U.S.A. Combination in L. (Myrafant): Smith, D.R. 1979: 1395; Combination in Temnothorax: Bolton, 2003: 272. See also: Mackay, 2000: 405.

Worker
Length 2;-2.25 mm. Head conspicuously narrow, with parallel sides, decidedly longer than broad, with straight posterior border. Mandibles 5-toothed. Clypeus moderately convex, its anterior border with a small but distinct excision in the center and a distinct median carina extending nearly its full length. Antennae 12-jointed; scape reaching the posterior corner of the head; first funicular joint as long as joints 2-4 together; second joint as long as broad; joints 3-8 nearly as long as broad; club distinctly 3-jointed, first and second joints subequal, together a little shorter than the terminal joint. Thorax rather long and narrow, widest in front where the humeral angles are sharp and prominent. In profile the pronotum rises very abruptly from the neck, so that a transverse ridge is formed which gives the thorax a square-shouldere appearance; dorsum flatly and evenly rounded, without mesoepinotal constriction. Epinotal spines well-developed, longer than broad at their bases, tapering and pointed, directed distinctly backward through slightly upward and outward; in profile the ventral outline of the spines is distinctly concave, the dorsal convex. They are about as long as their distance apart at the base. Petiole about 1 1/2 times as long as broad, distinctly broader behind than in front when seen from above; in profile the height of the node is fully equal to the length of the whole joint; its anterior surface is steep and somewhat concave, the top of the node abruptly truncated, the posterior slope so steep that it is even inclined forward below and forms somewhat less than a right angle with the extreme posterior dorsal surface of the petiole; ventral tooth well developed, directed downward. Postpetiole hardly twice as broad as the petiole, distinctly broader than long; its anterior wider than its posterior border, its anterior angles rather prominent. Gaster of the usual shape.

Mandibles not distinctly striated; shining, with a few coarse punctures. Clypeus shining, longitudinally rugose on the sides. Head very smooth and shining, covered with rather coarse but sparse piligerous punctures; sides of frontal area, cheeks and subocular region subopaque and delicately longitudinally rugose. Pro- and mesonotum very smooth and shining, with a few piligerous punctures passing over onto the pleurae into delicate longitudinal rugae, which become much coarser and distinctly reticulate on the sides and whole upper surface of the epinotum. Petiole and postpetiole opaque, reticulate and punctate-rugose. Gaster very smooth, shining.

Hairs white, only moderately abundant; clavate and erect on the thorax and crown of head, somewhat longer and more reclinate on the pedicel and gaster; the hairs on the sides of the head, antennae and legs non-clavate, appressed; those on the clypeus thin and projecting.

Very dark-brown, almost black. Mandibles, neck, funiculus and legs yellow; scape and club of antennae and the middle of the femora and tibiae infuscated; edges of mandibles black.

Type Material
Mackay (2000) - Colorado, Fremont Co., Canyon City. Four cotype workers,, [seen]."

Etymology
Commemorative. "Described from four specimens collected by Rev. P. J. Schmitt, O.S.B., to whom I take pleasure in dedicating this very striking species."

References based on Global Ant Biodiversity Informatics

 * Bestelmeyer B. T., and J. A. Wiens. 2001. Local and regional-scale responses of ant diversity to a semiarid biome transition. Ecography 24: 381-392.
 * 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.
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133