Dental Signatures for Exudativory in Living Primates, with Comparisons to Other Gouging Mammals.

Abstract

Exudativory, the consumption of gums, is an obligate or a facultative dietary niche for some primates and marsupials. Exudativory has been cited as a dietary niche that may have been present in early primates, so finding a dental signature for exudativory is highly desirable. The present study combines exudativorous lorisoids (galagos and lorises) into one sample to compare to closely related, non-exudativorous lorisoids to search for a consistent dental signature of exudativory. Linear measurements were taken from the toothcomb, P2 , M3 , upper canine, and P2 from skulls of 295 adult galagids and lorisids. Also, differential distribution of enamel on the anterior teeth was qualitatively investigated as a dental signature for gouging (a behavior that facilitates some exudativory) by micro-CT scanning one specimen each from two gougers, Nycticebus coucang and Callithrix jacchus, and two non-gougers, Perodicticus potto, and Saguinus fuscicollis. Non-primate gouging mammals, the vampire bat Desmodus rotundus and the sugar glider Petaurus breviceps, were compared to non-gouging relatives. Statistical analysis revealed that exudativorous galagos and lorises had significantly (P < 0.05) reduced M3 relative to non-exudativorous galagos and lorises. While the sample sizes for assessing enamel thickness were small, preliminary results show that gouging primates and non-primate mammals have reduced lingual enamel thickness on the anterior dentition compared to non-gouging relatives. We suggest that reduction of mastication, and, therefore, M3 dimensions are a likely dental signature for exudativory in Primates. While broader samples are needed to statistically confirm, differential distribution of enamel in the anterior dentition may also be a signature of exudativory. Anat Rec, 2019. © 2018 Wiley Periodicals, Inc. Anat Rec, 303:265-281, 2020. © 2018 American Association for Anatomy.