---

Bio

At Poster

Paper

Album

Shu Su
University of Michigan - Ann Arbor

Subject Listing - Animal Sciences
Advisor: Dr. Gregg Gunnell

Friday, Poster Session 5, Presentation Kiosk 35 A, Health & Fitness Center

EVOLUTION OF CAT-LIKE CARNIVORES, EVIDENCE FROM THE DENTITION

Carnivorous mammals with specialized dental adaptations for food processing have existed since the early Paleocene (60 million years ago). The evolutionary development of cat-like carnivores involves three significant stages: Oxyaenidae (a group of creodonts-carnivorous mammals, not directly related to the true carnivores) - fossil felids (cats) - extant (living) felids. Based on this concept, the plan during the second year of this four-year project mainly has been focused on measurements and comparative analysis of the teeth of the living carnivores and Oxyaenidae fossils. The purpose of this project for year two is to answer the question: What kind of creature (if any) filled the cat-like predator ecological niche during the Paleocene epoch. Tooth measurements were taken to quantify some aspects of dietary behavior. These measurements included canine length and width, lower fourth premolar length and width, lower first molar length and width, carnassial blade length and width as well as total crushing area of molar series. The results of the experiments illustrate that in most cases, premolars and molars of Oxyaenidae fossils appear to be very similar to those of living felid carnivores. Nevertheless, despite the similarity, subtle differences do exist. One is that the canines of fossils seem longer and thinner than those of modern cats. Another one lies in the molar - almost every molar has a substantial crushing area in Oxyaenidae, while in living cats the crushing area is reduced or absent. The third one is shown in the absence of premolar 1 and premolar 2 in living carnivores. These teeth are still present in oxyaenids. From these measurements and analysis, we can hypothesis that in the Paleocene, oxyaenids did fill an important role in the evolutionary history of cat-like carnivores. As the project progresses, further experiments will be done for the elucidation of the development and global exploitation of mammalian carnivorous adaptive zones.

Museum of Paleontology
University of Michigan

Advisor: Dr. Gregg Gunnell, Associate Research Scientist, Museum of Paleontology, University of Michigan, Ann Abor, MI