Lexi Keenan
Pronouns:
Research Mentor(s): Kevin Velez
Research Mentor School/College/Department: Earth and Environmental Sciences / LSA
Program:
Authors: Lexi Keenan
Session: Session 5: 2:40 pm – 3:30 pm
Poster: 44
Abstract
Fossil crocodylians from the Caribbean can be found in Eocene–Miocene (56–23 Ma) deposits in Cuba, Jamaica, and Puerto Rico, indicating that the group was well-established in the Caribbean millions of years ago. However, there is an apparent gap in the Dominican Republic with fossil crocodylians yet to be found. Recent paleontological excavations by members of the Museo Nacional de Historia Natural de Santo Domingo, University of Puerto Rico, and University of Michigan, however, found for the first time fossil remains of crocodylians in the Dominican Republic. Strontium (87Sr/86Sr) isotopic dating from invertebrate mollusks (Kuphus incrassatus) closer to the locality where the fossil remains were found, indicate a Miocene–Pliocene (7–4 Ma) age for the crocodylian remains. Over ten fossil vertebrae were shipped to the University of Michigan Museum of Paleontology for further preparation, description, and digitization (3D photogrammetry). Comparative analysis of the fossil vertebrae with those of similar age and extant forms found strong morphological similarities to the vertebrae of Crocodylia, the group that includes living crocodylians. Moreover, a recent discovery of a complete skull of a fossil gharial from the same stratigraphic unit suggests that these vertebrae possibly belong to the same species. Thus, these results show that this is one of the last gharial survivors from the Caribbean. The results of this project highlight the importance of using fossils for understanding past biodiversity. The 3D models of the vertebrae will be available for future research projects, teaching, and outreach programs at the University of Michigan.
