Pheidole psammophila

All of the nests found by Creighton and reported in Creighton and Gregg (1955), as well as by Stefan Cover (unpublished notes), were in sand, especially sand subject to frequent shifting, an extreme environment avoided even by other desert-dwelling ants.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. (Wilson 2003)

Identification
See the description in the nomenclature section.

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

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



Biology
The ecological responses of this ant appear to be unusually constant. Twelve colonies were found from stations whose elevation was never more than 250 feet above sea level. All the nests were constructed in areas whose dominating characteristic was an abundance of sand. The region of sand dunes, which extends through much of the Gran Desierto in Sonora and into Imperial County in California, appears to be an exceptionally difficult environment for most ants. Even the strongly xerophilous species avoid this area, presumably because the shifting sand is continually covering the nest openings. The presence of psammophila in this region indicates that the sand-dwelling habit is highly developed in this species. In areas where the sand was not shifting there were chaff piles around the nest entrances, a clear indication that psammophila is a harvester. (Creighton and Gregg 1955)

Worker
Minor

Nomenclature

 *  psammophila. Pheidole psammophila Creighton & Gregg, 1955: 15, figs. 4, 5 (s.w.) U.S.A. See also: Wilson, 2003: 593.

Description
From Wilson (2003): DIAGNOSIS A member of the “bicarinata complex” of the larger pilifera group, comprising Pheidole agricola, Pheidole aurea, Pheidole barbata, Pheidole bicarinata, Pheidole centeotl, Pheidole cerebrosior, Pheidole defecta, Pheidole gilvescens, Pheidole macclendoni, Pheidole macrops, Pheidole marcidula, Pheidole paiute, Pheidole pinealis, Pheidole vinelandica, Pheidole xerophila, Pheidole yaqui and Pheidole 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; smallsubpostpetiolar 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.



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

Type Material
CALIFORNIA: 8 km east of Grey’s Well, Imperial Co., 50 m, col. William S. Creighton. - as reported in Wilson (2003)

Etymology
Gr psammophila, sand-lover, referring to the nest-site preference. (Wilson 2003)