Dermatoglyphic patterns and pattern intensities of the genus Cacajao (Cebidae, platyrrhini) with observations on interspecific and subspecific differentiation.

Palmar and plantar dermatoglyphic pattern types, area and total pattern intensities (API and TPI), and pattern intensity (PI) profiles are presented for the South American genus Cacajao of the subfamily Pitheciinae. The data are based on prints from 41 bald-head uacaries (C. calvus), 9 white bald-head uacaries (C. c. calvus), and 15 black-head uacaries (C. melanocephalus). In each extremity, loops of differing orientation were the most frequent pattern type; whorls were dominant at palmar interdigital (I) area 3 in C. calvus and at both I3 and I4 in C. melanocephalus. Open fields characterized the palmar thenar and plantar proximal hypothenar, thenar, calcar, and I3 and I4. There was little evidence of significant sexual dimorphism as assessed from PI values. The genus displayed significant asymmetry at palmar I3 (P⩽0.001) and plantar distal hypothenar (P⩽0.004). There were significant group differences between C. calvus and C. c. calvus in the palmar thenar API and plantar TPIs. The combined bald-head sample of C. calvus and C. c. calvus differed from C. melanocephalus in API of palmar I4 and plantar distal thenar, I2, and distal hypothenar (marginally), and in plantar TPIs. In PI profiles, C. melanocephalus departed from the pattern shared by C. calvus and C. c. calvus in both palmar and plantar interdigital areas. As a genus, the uacaries have markedly low plantar TPI values relative to palmar values (palm-sole index > 195). Of eight comparison cebid genera, only Chiropotes, another pitheciine genus, approximated these values.