Pheidole casta

Pheidole casta is evidently a rare species. The type colony was found in a canyon of the Rio Grande, near Langtry, nesting in soil beneath cedars. The only other Texan record (R. E. Gregg, collector) is from Cameron Co., about 20 km east of Brownsville. (Wilson 2003)

Identification
See the description in the nomenclature section.

Distribution
Southern Texas. (Wilson 2003)

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

Nomenclature

 *  casta. Pheidole casta Wheeler, W.M. 1908e: 454, pl. 26, figs, 22, 23 (s.w.) U.S.A. See also: Wilson, 2003: 392.

Description
From Wilson (2003): A medium-sized, yellow member of the flavens group, whose major is characterized by its elongate head, shallow antennal scrobes, exclusively carinulate cephalic structure, conulate postpetiole, and slightly contrasting brownish spot on the center of the dorsum of the head capsule.

Similar to Pheidole mera, also of Texas, and distinguished from it by the less bulbous promesonotal profile in dorsal-oblique view, smooth occiput, and longitudinal (not oblique) orientation of the carinulae mesad to the eye.

MEASUREMENTS (mm) Lectotype major: HW 0.82, HL 1.14, SL 0.38, EL 0.14, PW 0.52. Paralectotype minor: HW 0.42, HL 0.48, SL 0.34, EL 0.06, PW 0.26.

COLOR Major: concolorous yellow, with a circular patch of slightly contrasting brownish yellow in center of dorsum of head.

Minor: concolorous clear yellow.

The minor worker from the Gregg colony collection has the head and mesosomal dorsum completely foveolate. Specimens from Estado Mexico (km 127, Highway 57) in the Museum of Comparative Zoology appear to belong to this species, although they are darker in color than the types (brownish yellow), and the sides of the heads of the minors are smooth and shiny.



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

Type Material
TEXAS: Canyon of the Rio Grande, Langtry, Texas, col. W. M. Wheeler. and - as reported in Wilson (2003)

References based on Global Ant Biodiversity Informatics

 * Wheeler, G.C. and J. Wheeler. 1985. A checklist of Texas ants. Prairie Naturalist 17:49-64.
 * Wilson, E.O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Genus. Harvard University Press