Comparative anatomy of the pelvic nerves in bearded capuchins (Sapajus sp)

Abstract

Bearded capuchins (Sapajus sp), unexpectedly, share with chimpanzees behavioral features such as high cognitive ability, good memory, tool use with intermittent bipedalism, and social tolerance; although its anatomy is still little studied. To test the hypothesis that bearded capuchins might share similar anatomical features with chimpanzees, we investigated the pelvic nerves of the bearded capuchin and compared them with the data in the previous literature for modern humans, chimpanzee, and baboons in terms of origin, trajectory and innervated structures, when the data are available. Variation is very common in the primates because of, inter alia, 1) the problem of the anatomical position, i.e., some primatologists used the human anatomical position to describe those in non-human primates, while others used the non-human anatomical position, and the definition of anatomical position (human or non-human position) is not clear; 2) the lateralized and semi-bend pelvis limbs in non-humans primates compared with modern humans; 3) the absence of the some muscles (e.g., scansorius and ilioschiofemoralis) in modern humans in the thigh; and 4) the difference in the numbers of vertebrae among the authors, even in the same species, such as chimpanzees and bearded capuchins.