Pheidole arachnion

A nest was found in rotting wood in forest at the La Selva Biological Station, near Puerto Viejo. (Wilson 2003)

Identification
See the description in the nomenclature section.

Distribution
Known from the Atlantic lowlands of Costa Rica. (Wilson 2003)

This taxon was described from Costa Rica.

Description
A member of the tristis group characterized by the following combination of traits.

Major: dark reddish brown; sides of head covered by loose rugoreticulum (i.e. with large interspaces); humeri and postpetiolar nodes seen from above comulate (hom-shaped); lacking any trace of antennal scrobes.

Minor: propodeal spine reduced to an obtuse angle; body entirely smooth and shiny except for several carinulae on anterior half of dorsal surface of head, one of which loops on each side of the head in a semicircle from the end of the frontal lobe to the anterior clypeal border; a thin nuchal collar present.

Very similar to Pheidole iracunda, also of Costa Rica, but differing in details in the characters as listed and illustrated.

MEASUREMENTS (mm) Holotype major: HW 1.80, HL 1.98, SL 0.76, EL 0.18, PW 0.90. Paratype minor: HW 0.60, HL 0.62, SL 0.74, EL 0.10, PW 0.40.

COLOR Major: body and mandibles dark reddish brown, other appendages light reddish brown. Minor: body plain medium brown, appendages brownish yellow.



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

Type Locality Information
COSTA RICA: Rio Reventazon, 3-5 km east of Turrialba, Cartago (William L. Brown).

Etymology
Gr arachnion, cobweb, alluding to the loose rugoreticulum on the head of the major.