Pheidole rhinoceros

In Costa Rica Longino (1997) found the species nesting in pieces of dead wood on the ground and, in one instance, beneath the loose bark of a 1-meter-wide tree trunk in an old treefall. At Guanacaste Conservation Area, in montane rainforest, he observed workers tending homopterans under loose bark. (Wilson 2003)

Identification
See the description in the nomenclature section.

Distribution
P. rhinoceros is at least locally common in upland forests to as high as 1100 m, from Honduras to Colombia. (Wilson 2003)

This taxon was described from Panama.

Description
From Wilson (2003): DIAGNOSIS Similar in various ways to Pheidole binasifera, Pheidole diabolus, Pheidole gravida, Pheidole mirabilis, Pheidole moseni, Pheidole mosenopsis, Pheidole nasifera, Pheidole unicornis, differing as follows.

Major: middle carina of clypeus raised into a right-angular hornlike protrusion, from which radiate carinulae traveling obliquely downward toward the anterior clypeal border; carinae originating on borders of frontal lobe curve inward toward the midline; posterior half of dorsal surface and all of pronotum smooth and shiny; propodeal spines slender, and vertical on the propodeal basal face.

Minor: propodeal spines short, slender, and vertical on the propodeal basal face; head entirely smooth. Longino (1997) notes that considerable variation exist in the sculpturing of the minors in at least Honduras and Costa Rica. At elevations of about 500 m or higher, minors tend to have more extensive foveolation on the pronotum and mesopleuron than do minors at lower elevations. In Costa Rica at least, the two forms are nowhere sympatric but in Braulio Carrillo National Park approach within 300 m elevation and about 5 km distance. The two forms may represent distinct species, but Longino treats them as conspecifics, and this more conservative arrangement appears appropriate for the time being.

MEASUREMENTS (mm) Lectotype major: HW 1.26, HL 1.40, SL 0.60, EL 0.16, PW 0.70. Paralectotype minor: HW 0.60, HL 0.64, SL 0.58, EL 0.10, PW 0.38.

COLOR Major and minor: concolorous light to medium brown.



'''Figure. Upper: major (side view, El Volcan Chiriqui, Panama, 900 m; full-face view, Cerro Campana, Panama, 800–950 m); compared with lectotype major. Lower: minor (Cerro Campana, Panama); compared with paralectotype. Scale bars = 1 mm.'''

Type Material
- as reported in Wilson (2003)

Type Locality Information
Type locality: Bugaba, Panama. (Wilson 2003)

Etymology
Species name inspired by the hornlike extension of the midclypeus. (Wilson 2003)