Undergraduate Honors Theses

Thesis Defended

Fall 2012

Document Type



Ecology and Evolutionary Biology

First Advisor

Dr. Andrew Martin


Hybridization is the interbreeding of separate species to create a novel species (hybrid). It is important to the study of evolution because it complicates the biological species concept proposed by Ernst Mayr (1963), which is widely adopted in biology for defining species. This study investigates possible hybridization between three stingrays of the genus Urobatis (Myliobatiformes: Urotrygonidae). Two separate loci were chosen for investigation, a nuclear region and the mitochondrial gene NADH2. Inability to resolve three separate species within the mitochondrial phylogeny indicate that gene flow has occurred between Urobatis maculatus, Urobatis concentricus, and Urobatis halleri. Additionally, the lack of divergence within the nuclear gene indicates that these three species are very closely related, and may even be a single species. Further investigation is recommended with a larger sample base and additional genes.