Pheidole cavigenis

According to Stefan Cover, who has collected intensively within the range of cavigenis, this species occurs in grassy gaps in juniper-oak-pinyon woodlands at mid-elevations. Nests are cryptic and seeds are sometimes found inside. Colonies appear to consist of no more than 200–300 individuals. (Wilson 2003)

Identification
See the description in the nomenclature section.

Distribution
Known from several collections in the Huachuca Mts; thence west to Sycamore Canyon in the Pajarito Mts., about 20 miles west of Nogales (Stefan Cover). A series in the Museum of Comparative Zoology from Bocoyna, Chihuahua, belongs to this species but with some differences; it may represent a geographical variant. (Wilson 2003)

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

Worker
Minor

Nomenclature

 *  cavigenis. Pheidole tepicana subsp. cavigenis Wheeler, W.M. 1915b: 403 (s.) U.S.A. Wilson, 2003: 567 (w.). Junior synonym of soritis: Gregg, 1959: 30. Revived from synonymy and raised to species: Wilson, 2003: 567.

Description
From Wilson (2003): DIAGNOSIS A member of the “pilifera complex” of the larger pilifera group; for a characterization of the complex, see under Pheidole pilifera. P. cavigenis is distinguished within the complex by the following combination of traits.

Major: occiput and extensive dorsal surface anterior to the occiput rugoreticulate; a small patch of rugoreticulum is present just posterior to each antennal fossa; humerus very prominent and lobose in dorsal-oblique view; mesonotal convexity absent, but mesonotum descends abruptly to the metanotal groove; propodeal spines long and thin; postpetiole spinose.

Minor: almost all of dorsal head surface longitudinally carinulate; propodeal spine needle-shaped.

MEASUREMENTS (mm) Major (Montezuma Pass, Arizona): HW 1.60, HL 1.86, SL 0.74, EL 0.22, PW 0.76.

Minor: HW 0.62, HL 0.66, SL 0.62, EL 0.12, PW 0.40.

COLOR Major: body light reddish brown, mandibles and gaster plain medium brown.

Minor: head and gaster medium brown, mesosoma and appendages light brown.



'''Figure. Upper: major. Lower: minor. ARIZONA: 11 km west-northwest of Montezuma Pass, Huachuca Mts., Cochise Co., 1660 m, col. Stefan Cover. Scale bars = 1 mm.'''

Type Material
- as reported in Wilson (2003)

Etymology
L cavigenis, hollow cheek, significance unknown. (Wilson 2003)

References based on Global Ant Biodiversity Informatics

 * Cole A. C., Jr. 1937. An annotated list of the ants of Arizona (Hymen.: Formicidae). [part]. Entomological News 48: 97-101.
 * Cover S. P., and R. A. Johnson. 20011. Checklist of Arizona Ants. Downloaded on January 7th at http://www.asu.edu/clas/sirgtools/AZants-2011%20updatev2.pdf
 * Johnson R. Personnal Database. Accessed on February 5th 2014 at http://www.asu.edu/clas/sirgtools/resources.htm
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Wilson, E.O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Genus. Harvard University Press