| Leptothorax crassipilis|
Wheeler, W.M., 1917
These ants nest in the soil, under stones or rarely in logs and stumps, in sandy loam to rocky loam soils. Brood and reproductives were found in nests from June to August, flights occurred in August. Most nest females are found simply under the stone, one gyne was at a depth of about 10-cm in the soil. This species may be polygynous, as one nest contained 2 dealate females. Colonies were found together with Myrmica hamulata, Camponotus vicinus, Formica lasioides and Formica occulta. (Mackay and Mackay 2002)
The clypeus of the worker is depressed in the middle and is without a medial carina, although several lateral carinae are present. The propodeal spines are well developed, and thickened at the bases. The anterior face of the petiole meets the dorsum in an angle, the posterior face is convex and rounded. The dorsum of the postpetiole is completely covered with punctate-granulose sculpture. The mesosoma has heavy and dense sculpture. There are numerous long (most over 0.1 mm), pointed (occasionally blunt) tipped hairs. (Mackay and Mackay 2002)
United States: Wyoming south to New Mexico, west to Nevada and Arizona. South into Mexico.
Distribution based on Regional Taxon Lists
Distribution based on specimens
Oak woodland, deciduous forests, ponderosa pine-riparian, Chihuahua pine, Douglas fir, spruce and fir forests, grasslands, subalpine fir, moist, shaded slopes as well as grassy, level, riparian areas. (Mackay and Mackay 2002)
Nevada, Wheeler and Wheeler (1986) - We have only 7 records from 4 localities. Two were from the Coniferous Forest Biome. Three nests were under stones.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- crassipilis. Leptothorax (Mychothorax) acervorum subsp. crassipilis Wheeler, W.M. 1917a: 513 (w.q.m.) U.S.A. Raised to species: Creighton, 1950a: 278. See also: Loiselle, Francoeur, Fischer & Buschinger, 1990: 329.
- Creighton, W. S. 1950a. The ants of North America. Bull. Mus. Comp. Zool. 104: 1-585 (page 278, Raised to species)
- Loiselle, R.; Francouer, A.; Fischer, K.; Buschinger, A. 1990. Variations and taxonomic significance of the chromosome numbers in the Nearctic species of the genus Leptothorax (s.s.) (Formicidae: Hymenoptera). Caryologia 43: 321-334 (page 329, see also)
- Mackay, W. P. and E. Mackay. 2002. The ants of New Mexico (Hymenoptera: Formicidae). Edwin Mellen Press, Lewiston, NY.
- Wheeler, G. C. and J. Wheeler. 1986. The ants of Nevada. Natural History Museum of Los Angeles County, Los Angeles.
- Wheeler, W. M. 1917a. The mountain ants of western North America. Proc. Am. Acad. Arts Sci. 52: 457-569 (page 513, worker, queen, male described)