Temnothorax schmittii

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

Temnothorax schmittii casent0172996 p 1 high.jpg

Temnothorax schmittii casent0172996 d 1 high.jpg

Specimen Labels

Only known from types.


Prebus (2017) - A member of the sallei clade.

Mackay (2000) - 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.

Keys including this Species


United States: Colorado.

Latitudinal Distribution Pattern

Latitudinal Range: 38.901104° to 20.3833°.

Tropical South

Distribution based on Regional Taxon Lists

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

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.


Only known from the type collection.


Explore-icon.png Explore Overview of biology 
Not much is known about the the biology of this taxon. We can speculate that its biology is likely to be similar to other North American species of this genus.

Temnothorax is a diverse genus but most species do show a remarkable consistency in some important aspects of their biology. Workers and colonies are small. As a group they nest in many places: small cavities in the soil, under or among stones or in small cavities in living or dead vegetation. Individually, most species have a strong preference for how and where they nest, e.g., there are gall nesting species, soil nesters, arboreal species, those that nest in small downed twigs, etc. Their nest entrances are often a cryptic, tiny hole that is only found by observing a worker exiting or entering the nest. A few common and abundant species are relatively well studied but the majority are rare or are rarely collected. For all but the most common and abundant species finding a nest is difficult because of the combination of their small colony size, small workers, unaggressive behavior, and diminutive, inconspicuous nests. In a few cases where we do know the diet of a species, it consists of sweet exudates and general scavenging of insect pieces and other items. It is presumed most of the unstudied Temnothorax have a similar diet. Aphid tending and hunting small soil arthropods may also be a part of their foraging repertoire. For all the consistency in these characters, individual species exhibit wide variation in others. Habitat affinities are often restrictive at the species level (but overall Temnothorax can be found in places that range from high elevation, high latitude, forests to hot, dry desert regions). Queen number is difficult to predict; there are species that are polygnous, monogynous, and even some species with seasonal polydomy that vary in nesting site queen number over the course of the year. There is also little consistency in color from species to species. ‎



The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • 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.

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



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.

Cotype Specimen Labels

Type Material

Mackay (2000) - Colorado, Fremont Co., Canyon City. Four cotype workers, American Museum of Natural History, Museum of Comparative Zoology [seen]."


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."


  • Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 272, Combination in Temnothorax)
  • MacKay, W. P. 2000. A review of the New World ants of the subgenus Myrafant, (genus Leptothorax) (Hymenoptera: Formicidae). Sociobiology 36: 265-444 (page 405, see also)
  • Prebus, M. 2017. Insights into the evolution, biogeography and natural history of the acorn ants, genus Temnothorax Mayr (hymenoptera: Formicidae). Bmc Evolutionary Biology. 17:250. doi:10.1186/s12862-017-1095-8 (The doi link to the publication's journal webpage provides access to the 24 files that accompany this article).
  • Smith, D. R. 1979. Superfamily Formicoidea. Pp. 1323-1467 in: Krombein, K. V., Hurd, P. D., Smith, D. R., Burks, B. D. (eds.) Catalog of Hymenoptera in America north of Mexico. Volume 2. Apocrita (Aculeata). Washington, D.C.: Smithsonian Institution Pr (page 1395, Combination in L. (Myrafant))
  • 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 242, pl. 12, fig. 14 worker described)

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