Research Training Program

Smithsonian Institution
National Museum of Natural History

PROJECT SUMMARY
1996

K. Rebecca Thomas
Samford University
Birmingham, Alabama
Lynne R Parenti, Ph.D.
Supervising Scientist
Department of Vertebrate Zoology
Division of Fishes
"The Research Training Program experience broadened my understanding of scientific research in a variety of natural history fields and provided a unique opportunity to interact with scientists in the museum setting."

The Phylogenetic Significance of Pharyngeal Tooth
Morphology in Sicydiine Gobiid Fishes (Teleostei: Gobiidae)

ABSTRACT
The fish family, Gobiidae, is in one of the largest groups of teleost fishes, the suborder Gobioidei, or the fish commonly known as gobies. The group's size is best understood upon realizing that approximately ten percent of all fishes are gobies. In addition to being a large group, gobies live in a variety of different habitats. This variation in habitat, in addition to variation in external morphology, causes confusion about classification of these fishes. Sicydiine gobies are a subfamily containing approximately 100 species of fishes in five genera whose adult forms live and breed in freshwater streams. In this study, variation in gill arch dentition was examined in order to discover characters useful in the identification and classification of sicydiine gobies and other members of the family Gobiidae. Because of the small size of the lower pharyugeal teeth, a set of teeth in the gill arches, Scanning Electron Microscopy (SEM) was used to survey tooth structure and modification. Observations revealed nine characters on the lower pharyngeal toothplates and revealed that the sicydiines do share characters states involving modification of the teeth. All five genera lack teeth on the anterior portion of the lower pharyngeal bones, and furthermore, four of the sicydiine genera have striated tooth tips. These two characters states are also shared by two other gobiid genera suggesting a relationship with the sicydiine subfamily. As more sicydiine characters are identified, relationships with other gobiid groups can be hypothesized resulting in a more stable classification of the family and ultimately, the suborder.

This research was supported by a grant from the National Science Foundation Research Experiences for Undergraduates program, Award Number DBI-9531331.

Letter of Gratitude