Pheidole chalca

Mann (in Wheeler 1914c) found numerous small colonies in oak-pine woodland near Molino Guerrero, an ore mill on the eastern slope of the mountain range east of Pachuca; they were nesting under stones. I found a nest of several chambers about 15 cm below the surface in the dense clay soil of Liquidambar woods adjacent to a meadow at approximately 1700 m on the south slope of Pico Orizaba. Workers were foraging along an adjacent trail. Sexual pupae were in the nest on 23 August. (Wilson 2003)

Identification
See the description in the nomenclature section.

Distribution
Hidalgo and Veracruz, Mexico. (Wilson 2003)

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Nomenclature

 *  chalca. Pheidole chalca Wheeler, W.M. 1914b: 44 (s.w.q.) MEXICO. See also: Wilson, 2003: 396.

Description
From Wilson (2003): A small-medium species, with angulate postpetiole and bicolorous head in the major. Similar to Pheidole nitidicollis, but distinguished in the major by the smooth humerus, which is less prominent in dorsal-oblique view; broader, angular-sided postpetiolar node; and yellow occiput; and in the minor by the unarmed humerus and smooth pronotal dorsum.

Also similar but less so to Pheidole arhuaca, Pheidole caulicola, Pheidole mincana, Pheidole sagana, Pheidole schmalzi and Pheidole tragica, differing in details of body shape, and sculpture as illustrated, and color.

MEASUREMENTS (mm) Lectotype major: HW 1.04, HL 1.24, SL 0.54, EL 0.14, PW 0.52. Paralectotype minor: HW 0.52, HL 0.60, SL 0.50, EL 0.12, PW 0.38.

COLOR Major: anterior third of head and occiput yellow, remainder of head brown; body yellowish to light brown; appendages light yellow. Minor: brownish yellow.



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

Type Material
MEXICO: Molino Guerrero (Guerrero Mill), Hidalgo, 2600–2700 m, col. W. M. Mann. - as reported in Wilson (2003)

Etymology
Presumably from Gr chalkos, copper, alluding to the body color. (Wilson 2003)

References based on Global Ant Biodiversity Informatics

 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Fernandes, P.R. XXXX. Los hormigas del suelo en Mexico: Diversidad, distribucion e importancia (Hymenoptera: Formicidae).
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * 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