Pheidole cataractae Wheeler

Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA, USA: Harvard University Press : 178

Pheidole cataractae Wheeler

Pheidole cataractae Wheeler 1916c: 6.

Types Mus. Comp. Zool. Harvard.

etymology Gr cataract, waterfall, alluding to the Kaieteur Fall, at the type locality.

diagnosis A brown, unusually small and slender member of the diligens group.

Major: body mostly smooth and shiny, with portions of mesosoma and propodeum foveolate, and with widely spaced longitudinal carinulae over part of dorsal head surface, their interspaces foveolate or smooth and shiny. Minor: very slender; propodeal spines reduced to denticles.

A media, possibly a developmental anomaly, was found in a series from Cuzco Amazonico, in Amazonian Peru.

Close to calimana , distinguished from that species by its well-developed propodeal spines and shorter cephalic carinulae in the major and smooth, shiny head in the minor.

Measurements (mm) Lectotype major: HW 0.94, HL 0.94, SL 0.76, EL 0.14, PW 0.44. Paralectotype minor: HW 0.42, HL 0.50, SL 0.64, EL 0.10, PW 0.28.

color Major: body medium brown, with mandibles and anterior quarter of head capsule dark yellowish brown; antennae and legs medium yellowish brown.

Minor: body concolorous light brown, appendages a lighter shade of yellowish brown.

Range Known from one locality each in Guyana, north of Manaus in Brazil, and Cuzco Amazonico, near Puerto Maldonado, Madre de Dios, Peru.

Biology Nests in pieces of rotting dead wood on the floor of rainforest. A media (minor-major intercaste) was found in the Peruvian series. Having studied a colony I collected north of Manaus and maintained in the laboratory, I agree with the following assessment by Stefan Cover (personal communication), based on his experiences at Cuzco Amazonico: " P. cataractae belongs to a small guild of rainforest Pheidole characterized by agile, fast-moving workers and soldiers [majors] with relatively long appendages; it nests in ephemeral sites on the forest floor and finds food sources rapidly, but retreats if competition shows up." The adaptation represents a behavioral (and in long appendages, anatomical) convergence to many species of the formicine genus Paratrechina .

Figure Upper: lectotype, major. Lower: paralectotype, minor, on top; and head, mesosoma, and waist, a minor from Fazenda Dimona, 90 km north of Manaus, Brazil (E. O. Wilson). (Type locality: Kaieteur, Guyana.) Scale bars = 1 mm.