Pheidole nigricula ^HNS new species

types Mus. Comp. Zool. Harvard.

Etymology L nigricula ^HNS, little dark one.

Diagnosis Similar in various traits to the species listed in the heading, differing as follows.

Major: blackish brown; very small; head elongate; frontal triangle not demarcated; eyes placed well forward on head; humerus low and lobate; propodeal spines equilaterally triangular; postpetiole from above elliptical; dorsal surface of head, including occiput but not midclypeus, foveolate; mesosoma almost entirely smooth and shiny.

Minor: carinulae limited to antennal fossae; all of head and mesosoma smooth and shiny; propodeal spines moderately long, and thin;

occiput broad, its margin weakly concave, and lacking nuchal collar.

measurements (mm) Holotype major: HW 0.56, HL 0.70, SL 0.26, EL 0.10, PW 0.34.

Paratype minor: HW 0.34, HL 0.40, SL 0.30, EL 0.06, PW 0.24.

color Major: concolorous blackish brown, appendages medium brown.

Minor: sides of mesosoma medium to dark reddish brown; rest of body, and appendages, dark, almost blackish brown.

Range Atlantic lowlands to 800 m in Costa Rica (Longino 1997).

biology This tiny species inhabits mature rainforest where it nests in rotten hollow twigs in leaf litter on the forest floor.

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