Geissmann T., 1987: Occurrence of sternal and axillary glands in hominoids. Chemical Senses 12: 177-178 (Abstract only).

Occurrence of sternal and axillary glands in hominoids

T. Geissmann

Anthropological Institute, University Zürich-Irchel

Although glandular structures in the sternal region are known to occur in many primate species, in hominoids such a gland is only known of in the orang-utan. In the latter, the gland has been thought to be in a stage of regressive evolution. This report presents evidence for the occurrence of a sternal gland in at least two species of gibbons (Hylobates syndactylus and H. agilis). In contrast to the sternal gland, the axillary glandular organ is present only in the hominoid genera Gorilla, Pan and Homo, none of which is reported to possess a sternal gland. Attention is drawn to the complementary occurrence of sternal and axillary glands in hominoids. It has repeatedly been proposed that the sternal gland in primates might be a retained primitive feature, whereas the axillary gland of man and the African apes has been interpreted as a derived, synapomorph characteristic. The possibility is discussed here that disappearance of the sternal gland and appearance of the axillary gland occurred not only in temporal, but also in functional, interconnection during hominoid evolution.