Dissertation Research: Ontogeny and Anatomy of the Skeleton in Mooneyes and Goldeyes and the Systematics of Hiodontiform Fishes

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

0073066 Bemis and Hilton With over 24,000 living fish species, Teleostei includes over half of all living vertebrate animals. Such a large diversity offers outstanding chances for discoveries in evolutionary biology. However, we still lack much information about teleostean anatomy and there is little consensus about such basic questions as the evolutionary origin and diversification of teleosts. To address these issues, graduate student Eric Hilton, under the direction of Dr. William Bemis, proposes a two-part study. First, he will describe in detail (for the first time) the skeletons of two North American teleosts known as mooneyes and goldeyes (genus Hiodon) on the basis of extensive series of specimens both geographic (to assess variability) and ontogenetic (to assess developmental changes from juvenile to adult form). The mooneyes and goldeyes belong to an early evolutionary radiation of teleosts that also contains such familiar species as knife fishes, elephant nose fishes, and arowanas. This group is believed to have split from all other teleosts approximately 150 million years ago, and the skeleton of mooneyes and goldeyes has remained largely unchanged since this time. For this reason, they can be used to represent early teleosts in studies of teleostean evolution. Second, the student will use the new anatomical information generated by the study for a broad analysis of teleostean phylogeny. A focused comparative survey of skeletal characteristics in more than thirty living and fossil teleostean species will build upon the first-hand observations of specimens used in the study. The reconstructed patterns of teleostean evolutionary diversification can then be compared with patterns developed by other researchers, including molecular systematists. Ultimately the morphological and molecular data on fishes can be synthesized to yield a reliable account of the origins and diversity of living teleosts.