Pheidole cataractae

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 Amazónico: “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. (Wilson 2003)

Identification
See the description in the nomenclature section.

Distribution
Known from one locality each in Guyana, north of Manaus in Brazil, and Cuzco Amazónico, near Puerto Maldonado, Madre de Dios, Peru. (Wilson 2003)

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Guyana, Peru.

Nomenclature

 *  cataractae. Pheidole cataractae Wheeler, W.M. 1916c: 6 (s.w.) GUYANA. See also: Wilson, 2003: 178.

Description
From Wilson (2003): 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 Amazónico, in Amazonian Peru. Close to Pheidole 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.



'''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, col. E. O. Wilson. Scale bars = 1 mm.'''

Type Material
Kaieteur, Guyana. - as reported in Wilson (2003)

Etymology
Gr cataract, waterfall, alluding to the Kaieteur Fall, at the type locality. (Wilson 2003)