Pheidole williamsi Wheeler

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA, USA: Harvard University Press : 249

Pheidole williamsi Wheeler

Pheidole williamsi Wheeler 1919d: 267. Syn.: Pheidole williamsi var. seymourensis Wheeler 1924b: 108, n. syn. types Mus. Comp. Zool. Harvard.

Etymology Named after Harrison Williams, leader of a Galapagos collecting expedition.

diagnosis A small, yellow member of the diligens group, closest to crozieri of Peru, but also with some similarities to vafella , as well as rufipilis and the mostly South American species listed with rufipilis (q.v.), differing from crozieri as follows.

Major: dark yellow; pronotum in side view peaked in a blunt angular profile, and weakly bilobous in dorsal-oblique view; occiput weakly concave; anterior margin of pronotal dorsum carinulate; apex of petiolar node in side view tapering to a blunt point.

Minor: petiolar node in side view relatively low, and in rear view with dorsal border strongly convex.

Measurements (mm) Lectotype major: HW 1.04, HL 1.10, SL 0.74, EL 0.16, PW 0.52.

Paralectotype minor: HW 0.48 (approximately), HL 0.62, SL 0.66, EL 0.12, PW 0.30.

color Major: concolorous dark yellow.

Minor: body brownish yellow, appendages dark to medium yellow.

The Wheeler types may be faded; minors collected on Isla San Salvador in 1991 (P. Oromi) have light brown bodies.

range Known only from Isla Santa Cruz, Isla Seymour, and Isla San Salvador. An apparent endemic of the Galapagos Islands. The species appears to be rare.

Biology Males were collected with the lectotype series in November 1905.

Figure Upper: lectotype, major. Lower: paralectotype, minor. GALAPAGOS ISLANDS: Isla Santa Cruz. Scale bars = 1 mm.