Pheidole psammophila

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press : 593

Pheidole psammophila Creighton and Gregg

Pheidole psammophila Creighton and Gregg 1955: 15.

Types Mus. Comp. Zool. Harvard.

Etymology Gr psammophila , sand-lover, referring to the nest-site preference (see below).

diagnosis A member of the " bicarinata complex" of the larger pilifera group, comprising agricola , aurea , barbata , bicarinata , centeotl , cerebrosior , defecta , gilvescens , macclendoni , macrops , marcidula , paiute , pinealis , vinelandica , xerophila , yaqui , and yucatana ( psammophila is closest to barbata ), which complex is characterized by the large to very large, forward-set eyes of both castes; and, in the major, the occipital lobes lacking any sculpturing (except in aurea ); the posterior half of the head capsule almost entirely smooth and shiny; and the postpetiolar node seen from above oval, elliptical, or laterally angulate (cornulate in cerebrosior ). P. psammophila is distinguished within the complex by the following combination of traits.

Major: hypostoma lacking teeth; humerus in dorsal-oblique view subangulate; petiolar node in side view tapered to a point; small subpostpetiolar process visible in side view; occipital lobes subangulate.

Minor: lower surface of head flat and bearing very long hairs curved to form a basket (psammophore). Petiole long and thin and petiolar and postpetiolar nodes very low.

Measurements (mm) Syntype major: HW 1.60, HL 1.72, SL 0.80, EL 0.30, PW 0.72. Syntype minor: HW 0.54, HL 0.68, SL 0.62, EL 0.24, PW 0.38.

color Major: head and mandibles clear reddish yellow, mesosoma and waist medium reddish brown, gaster and appendages light reddish brown.

Minor: body concolorous medium brown, mandibles a contrasting clear yellow, other appendages light brown.

Range Sandy deserts of southern California, western Arizona, and Sonora, northern Mexico, sea level to 75 m (Creighton and Gregg 1955).

Biology All of the nests found by Creighton and reported in Creighton and Gregg (1955), as well as by Stefan Cover (unpublished notes), were in sand, especially sand subject to frequent shifting, an extreme environment avoided even by other desert-dwelling ants. The remarkable psammophore (basket-like enclosure of hairs between the head, used to carry sand or other loose particles) is likely an adaptation to the environment for which the species is specialized. Chaff piles occurred around the nest entrances of some of the nests, an almost certain sign that psammophila harvests seeds.

Figure Upper: syntype, major. Lower: syntype, minor. CALIFORNIA: 8 km east of Grey's Well, Imperial Co., 50 m (William S. Creighton). Scale bars = 1 mm.