Pheidole cerebrosior

Creighton and Gregg (1955) report that the preferred habitat of cerebrosior is evergreen-oak-woodland in mountain canyons, with open desert less frequently occupied. The colonies are always small, and contain no more than 3 or 4 majors. Stefan Cover (unpublished specimen data) found numerous colonies in open Ephedra, mesquite, and mesquite-acacia desert, as well as riverine cottonwood forest, nesting variously under rocks beneath cow dung, and in open soil with multiple small crater nests. He found seed chambers in some nests and observed workers feeding on a dead beetle. A winged queen has been collected on 1 July. In Nevada, G. C. and Jeanette N. Wheeler (1986) found a single colony under a half-buried stone in yucca-larrea desert. (Wilson 2003)

Identification
See the description in the nomenclature section.

Distribution
From Wilson (2003): Arizona and New Mexico, 550 to 1680 m; southern California, 950 m; Baja California, 640 m; Chihuahua, 1500 m (Creighton and Gregg 1955); numerous records by Stefan Cover (collection notes) and extreme southern Nevada (G. C. and J. Wheeler 1986).

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

Nomenclature

 *  cerebrosior. Pheidole vinelandica subsp. cerebrosior Wheeler, W.M. 1915b: 405 (s.w.) U.S.A. Raised to species: Creighton, 1950a: 175. See also: Wilson, 2003: 569.

Description
From Wilson (2003): DIAGNOSIS A member of the “bicarinata complex” of the larger pilifera group; for a characterization of the complex, see under Pheidole bicarinata.

P. cerebrosior is distinguished within the complex by the following combination of traits.

Major: postpetiole seen from above very wide and conulate; propodeal spines well-developed and backward-directed; pronotal humeri with short irregular carinulae.

Minor: mesosomal pilosity comprises rows of evenly spaced pairs of erect hairs.

MEASUREMENTS (mm) Lectotype major: HW 1.12, HL 1.32, SL 0.60, EL 0.14, PW 0.58. Paralectotype minor: HW 0.46, HL 0.56, SL 0.44, EL 0.12, PW 0.28.

COLOR Major: body light reddish yellow, except for the gaster, which is a slightly contrasting yellowish brown.

Minor: concolorous plain yellow.



'''Figure. Upper: lectotype, major. Lower: paralectotype, minor. Scale bars = 1 mm.'''

Type Material
and - as reported in Wilson (2003)

Type Locality Information
ARIZONA: Tucson. (Wilson 2003)

Etymology
Unkown