Pheidole obtusospinosa Pergande

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press : 587

Pheidole obtusospinosa Pergande

Pheidole obtusospinosa Pergande 1896: 889. Junior synonym of Pheidole subdentata Pergande 1896: 888, synonymy by Wheeler, 1914c: 50; subdentata Pergande is ajunior secondary homonym of Oecophthora subdentata Mayr 1853b: 145, later transferred to Pheidole and a synonym of P. pallidula (Nylander) of Eurasia; hence obtusopilosa is first available name. Syn.: Pheidole arizonica Santschi 191 ld: 3, synonymy by Creighton 1958: 211.

Types Nat. Mus. Nat. Hist. U. S.

Etymology L obtusospinosa , with blunt thorns, referring to the propodeal spines.

Diagnosis A large trimorphic species placed in the pilifera group because of the 2-toothed hypostoma of the major but with other traits conforming to the fallax group. Very close to hirtula , distinguished most readily in the supermajor, as illustrated, by the elongate foveae of the rear half of the dorsum of the head, with the interspaces densely foveolate and opaque. The tangled taxonomic history of this species and the true status of vaslitii , previously associated with it but now revealed as a junior synonym or sibling species ofhyatti (q.v.), have been presented by Ward (2000).

Measurements (mm) Supermajor: HW 2.50, HL 2.36, SL 1.12, EL 0.26, PW 1.06.

Major: HW 1.44, HL 1.46, SL 1.12, EL 0.24, PW 0.72.

Minor: HW 0.62, HL 0.80, SL 0.98, EL 0.16, PW 0.44.

Color All castes: yellowish to reddish brown.

Range Known from the mountains of southern Arizona at 300-1900 m, and from Nayarit to Nuevo Leon in Mexico.

biology Stefan Cover (unpublished field notes), who has collected obtusospinosa many times in southern Arizona, has found it consistently in woodland, variously composed of different combinations of pine, oak, and juniper. It typically nests under rocks, although Cover found one colony beneath a cow pat and another 2.5 m from the ground in the dead branch of a standing oak tree ( Quercus arizonica ). Creighton (1958) reports that colonies are much smaller than those of the closely related hirtula , and that in southern Arizona nuptial flights occur in early July.

Figure Upper: major, with heads of major (left) and supermajor (right). Lower: minor. ARIZONA: Sunnyside Canyon, Huachuca Mts., Cochise Co. (Stefan Cover). (Type locality: Tepic, Nayarit, collected by Eisen and Vaslit.) Scale bars = 1 mm.