Pheidole arietans, Wilson, E. O., 2003

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press : 657

Pheidole arietans new species

Types Mus. Comp. Zool. Harvard.

Etymology L arietans , ramlike, referring to the forward-projecting frontal lobes of the major.

Diagnosis A distinctive member of the tristis group characterized by the following traits.

Major: in side view, frontal lobe forms a conspicuous triangular projection; parallel transverse carinulae encircle the posterior half of the head; a wide band of rugoreticulum stretches from the posterior ends of each frontal lobe to the eye; the two frontal lobes are covered by a common set of parallel semicircular carinulae; promesonotum and propodeum covered by longitudinal carinulae. Minor: occiput broad, lacking a nuchal collar; margins of pronotal dorsum and all of mesonotal dorsum with transverse carinulae. Close to glyphoderma , also of Costa Rica, but differing in many features of body form and sculpturing as illustrated. measurements (mm) Holotype major: HW 1.18, HL 1.34, SL 0.64, EL 0.16, PW 0.66. Paratype minor: HW 0.56, HL 0.60, SL 0.56, EL 0.12, PW 0.38.

color Major: posterior four-fifths of head capsule, and all of mesosomal dorsum, waist, and gaster dark brown; clypeus, a strip just posterior to the clypeus, mandibles, and side of mesosoma medium reddish brown; antennae and legs brownish yellow. Minor: body concolorous medium brown, appendages yellow to light brownish yellow.

Range Atlantic slope of Costa Rica from near sea level to 1000 m elevation (in Braulio Carrillo National Park) (Longino 1997).

Biology The type colony was collected by Stefan Cover in a hollow rotten stick on the floor of mature lowland rainforest. Seeds were present in the nest. Longino (1997) found one nest in a very wet rotten log, and others in internodes of Cecropia seedlings, as well as live stems of Myriocarpa along streams. One arboreal nest was found in a hollowed-out section ofa live branch in a fresh treefall; this colony had a seed cache.

figure Upper: holotype, major. Lower: paratype, minor. COSTA RICA: La Selva Biological Station, near Puerto Viejo, Heredia (Stefan Cover). Scale bars = 1 mm.