Research Training Program

Julianne Rowehl
Southampton College
Southampton, NY

Carole Baldwin, Ph.D
Drs. Victor Springer & Lynne Parenti
Supervising Scientists
Department of Systematic Biology
Division of Fishes

"My time spent here helped me decide what I will study in graduate school and gave me the opportunity to work with some of the most distinguished scientists."

Identification of Galapagos Entomacrodus with comments on relationships within the Entomacrodus "nigricans" species group

Documenting biodiversity is important for understanding the complexity of ecosystems, as a foundation for future conservation decisions, and for understanding evolution in a historical context. Comparative morphological studies provide the basis for recognizing biological diversity. These studies involve careful comparisons of the anatomy of organisms, including superficial features and internal structures such as bones and cartilage. When a population of animals belonging to a known genus is discovered in a geographical area in which the genus has not been recorded previously, morphological comparisons with other known species of the genus are needed to identify the new population. In this study, fish of the tropical blenny genus Entomacrodus were collected from the Galapagos Islands in the eastern Pacific Ocean. This fish has never been reported from Galapagos. A comparative morphological study was performed, and the fish was identified as Entomacrodus chiostictus, a widespread species in the eastern Pacific. A study was then performed to examine relationships of 10 fish species within this genus. The main differences between the species in the genus are the coloration patterns, and detailed comparisons of numerous external and internal features in this study revealed few other differences. Color patterns are usually extremely important in fish because the females and males often recognize each other on the basis of these patterns. It has been hypothesized that Entomacrodus originated in the central Pacific Ocean and moved eastward to the eastern Pacific and Atlantic. Results of this study support a Pacific origin of the genus and suggest a close relationship among Atlantic members of the genus and E. chiostictus. Because the 10 species studied are so similar to one another anatomically, hypotheses of relationships within the group (based on morphology) are not well supported. Molecular data may provide more insight into the evolution of this fish genus.

This research was supported by a grant from the Smithsonian Women's Committee.

Letter of Gratitude