Pheidole acutidens (Santschi) Bruchomyrma acutidens Santschi 1922e: 249. Combination with Pheidole by Wilson 1984b: 327. Types Naturhist. Mus. Basel. etymology L acutidens, sharp-pointed tooth apparently referring to the reduced, acute mandible. diagnosis An extreme workerless social parasite of Pheidole nitidula, with adaptations that make it unique within the genus. Queen: with 9- to 11-segmented antennae and minute, falcate toothless mandibles that taper to needle-sharp points. Male: pupiform, with mandibles vestigial or absent. measurements (mm) Syntype queen: HW 0.40, HL 0.42, SL 0.72, EL 0.12, PW 0.58. Color Queen: yellowish brown. Range Known only from the type locality. Biology P. acutidens is a permanent workerless parasite of Pheidole nitidula. The discoverer of this remarkable species, Carlos Bruch (1931), has provided extensive notes on its anatomy, ecology, behavior, and life cycle. Figure Queen. ARGENTINA: La Plata, Buenos Aires (Carlos Bruch). Type locality: Alta Gracia (La Granja). Sierra de Cordoba, Argentina. Scale bar = 1 mm.

Published as part of Wilson, E. O., 2003, Pheidole in the New World. A dominant, hyperdiverse ant genus., Cambridge, MA :Harvard University Press on page 260