Evolution of the primate vomeronasal system: fossil evidence from the Fayum

Date
2017-04-01
DOI
Authors
Garrett, Eva C.
Gonzales, Lauren A.
Kirk, E. C.
Seiffert, Erik R.
Version
First author draft
OA Version
Citation
Eva C Garrett, Lauren A Gonzales, E.C. Kirk, Erik R Seiffert. 2017. "Evolution of the primate vomeronasal system: fossil evidence from the Fayum." AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY. 86th Annual Meeting of the American-Association-of-Physical-Anthropologists (AAPA). New Orleans, LA, 2017-04-19 - 2017-04-22. Volume162, Issue1, Pages 191-196.
Abstract
Extant primates vary dramatically in the presence and development of the vomeronasal system (VNS), which largely detects social pheromones and anti-predator chemosignals. While the strepsirrhine VNS resembles most mammals, haplorhines either have derived VNS traits with ambiguous effects on vomeronasal function, or have lost the system entirely. While a reduced reliance on vomeronasal olfaction in haplorhines is inferred, few studies have addressed VNS variation in extinct primates to examine the timing and context of the loss of this system. We have previously identified an osteological correlate of the vomeronasal organ, the vomeronasal groove (VNG), which allows us to implement a paleontological approach toward understanding primate VNS evolution. We investigated cranial material of fossil primates for the presence or absence of a VNG using microCT scans. The VNG was present in a broad temporal and taxonomic range of primate fossils, including plesiadapiforms, adapiforms, omomyoids, crown platyrrhines, stem anthropoids, and stem catarrhines. Notably the VNG persists as a relatively small gutter in the stem catarrhine Aegyptopithecus zeuxis, but is absent in advanced stem catarrhine Saadanius hijazensis, and the Miocene cercopithecoid Victoriapithecus. We estimate that VNG loss occurred between 30-28ma, based on our sample. These dates complement estimates for the accelerated rate of deleterious mutations, and loss of function, in the TRPC2 pheromone transduction gene in catarrhines between 40-25ma. Further exploration of the VNG in fossil primates will lead to a more thorough understanding of past sensory environments and their ultimate effects on sensory specializations of extant lineages.
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