Pheidole obscurior, Wilson, E. O., 2003

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA: Harvard University Press : 330

Pheidole obscurior Forel, new status

Pheidole susannae r. obscurior Forel 1886b: xliv. Syn.: Pheidole partita Mayr 1887: 590, n. syn. Types Mus. Hist. Nat. Geneve.

etymology L obscurior , darker, presumably in comparison to the yellow susannae .

diagnosis A member of the fallax group, closest to susannae but also resembling haskinsorum , lattkei , and petrensis , and distinguished as follows.

Major: color mostly light to medium brown; head sometimes bicolorous, as illustrated, and described below; antennal scape reaching slightly beyond occipital comer; rugoreticulum extensive around eye but not laterad to it; humerus subangulate in dorsal-oblique view; pronotum carinulate; mesosoma and waist entirely foveolate and opaque, but first gastral tergite entirely smooth and shiny; petiolar node in side view tapering to a blunt point. Minor: occiput moderately narrowed, with nuchal collar.

measurements (mm) Lectotype major: HW 1.32, HL 1.44, SL 1.04, EL 0.20, PW 0.64.

Paralectotype minor: HW 0.60, HL 0.80, SL 1.02, EL 0.16, PW 0.44.

Color Major: light to medium reddish brown, with reddish tinge very slight.

Minor: concolorous brownish yellow.

Range Reported by Kempf (1972b) from Santa Fe and Misiones, Argentina; southeastern Brazil; Colombia; Trinidad; St. Vincent; Costa Rica; and Guatemala. I have been able to verify series from Rio de Janeiro, Sao Paulo, and Meta, Colombia.

Biology Colonies collected by H. H. Smith on St. Vincent and identified by Forel (1893j) as obscurior were in logs and other pieces of rotten wood in or near forests. They were populous, containing 500-1000 individuals, and aggressive when disturbed. The species was considered by Smith to be rare. He found winged queens and males in nests in early November.

figure Upper: major. Lower: minor. BRAZIL: Caraguatatuba Reserva Floresta, Sao Paulo, 40-80 m (William L. Brown). Major and minor compared with lectotype and paralectotype by E. O. Wilson. (Type locality: Guanabara, Rio de Janeiro, Brazil.) Scale bars = 1 mm.