LIVE OAK, VERY DEAD FISH: AN ANATOMICAL DESCRIPTION OF A LEGACY COLLECTION OF MIOCENE FISH FOSSILS FROM LIVE OAK COUNTY, TX

This study examines a legacy collection of fish fossils from the David Fitzgerald Museum of Earth Sciences (St. Mary’s University). The limited documentation indicates that the fossils were collected in the 1970s, from an Exxon uranium pit in Live Oak County, Texas. Previous work determined that these fossils represented at least 26 individuals and at least two species, one cyprinid and one carnivorous non-cyprinid. Previous work also determined that the fossils were from the late Oligocene or early Miocene, meaning that these are the only Tertiary freshwater fishes known from the South Texas Coastal Plain, and that the cyprinid is the earliest known representative of the Cyprinidae in Texas. The current research seeks to better clarify the phylogeny of these fossils. Six different non-vertebral elements (opercular, pharyngeal, parasphenoid, maxillae, hyomandibulae, and dentary) were qualitatively analyzed and described. In addition, over 200 separate vertebral elements were quantitatively analyzed using a hierarchical cluster analysis and Kruskal-Wallis test, which determined the presence of several unique clusters within the trunk and caudal vertebrae, presently thought to represent different age groups. The qualitative analyses and comparison to previous literature showed that the opercular bones bear a very close resemblance to those of the common minnow Phoxinus phoxinus; the articular arm and articular facet are identical, and the only notable differences in the opercular are that the unknown cyprinid is larger and bears an unusual upward-curving auricular process. Based on this we can tentatively conclude that our cyprinid is a minnow from the subfamily Leuciscinae, most likely belonging to the phoxinini clade.