Meeting Abstract
Dental eruption patterns are largely controlled by genetics and often exhibit a strong phylogenetic signal. In many mammals, the timing of dental eruption is an adaptive response to diet and life history strategy. We examined postcanine eruption patterns in 86 genera of ungulates spanning 11 families and five major clades of Artiodactyla and Perissodactyla. All specimens are held at the Museum of Vertebrate Zoology and the National Museum of Natural History. We visually examined specimens at multiple ontogenetic stages with earlier and/or more complete eruption of either the fourth premolar or the third molar being used to identify dental eruption patterns. Of the 51 ruminant genera for which we could definitively assess the postcanine dental eruption pattern, 46 genera share a dental replacement pattern where the fourth premolar erupts later than all molars. Five genera of Family Bovidae deviate from this pattern with three genera erupting their fourth premolars and third molars approximately simultaneously, and two genera, both in Subfamily Caprinae, erupting their third molars last. All of the closest terrestrial relatives of the ruminants erupt the third molar last suggesting that late premolar eruption in ruminants is directly related to phylogeny. Dental eruption patterns in early fossil Artiodactyla indicate that eruption of the third molar last may be the basal condition. Further examination of the fossil record will help inform the evolution and possibly adaptive advantage of this trait in the ruminants. This project was supported by the Department of Integrative Biology and the Museum of Vertebrate Zoology, UC Berkeley.
