Jeremy Harris Thesis Defense: Project Description
Title: The Comparative Morphology of the Pectoral Free Rays in Scorpaenoidea Fishes (Scorpaenoidea: Perciformes)
ABSTRACT
The majority of teleost fishes utilize their pectoral fins to assist in swimming locomotion. However in many benthic taxa, the fins have been freed from this role and have evolved novel functions. One such group, the searobins (Triglidae: Scorpaenoidea) utilizes its pectoral fins in a unique and unusual way. In this group, three of the pectoral fin rays have become separated from the fin as a whole, allowing them to operate as a separate appendage from the fin as a whole. These “free rays” are thought to allow for specialized interactions with the substrate and they support unique sensory functions and locomotive behaviors. The anatomical structure of this trait was investigated and several previously unreported muscle and bone variations were found that distinguish the free rays from the rest of the pectoral fin. This method was extended to include members of four other scorpaenoid families which possess free rays. Although externally similar, dissection revealed important differences in the muscle, bone, and nervous structure of this trait. Geometric morphometric analysis of the osteology of major free ray components displays family specific patterns in the attachment of muscles and shape of bone processes. Overall, these data are congruent with current phylogenetic hypotheses and point to at least two divergent patterns in free ray and pectoral fin evolution. The anatomical diversity of this trait, coupled with behavioral observations, suggests that it has evolved multiple times and has taken on unique specialized roles in each taxon.
Acknowledgement
I would like to thank the many people who helped to make this thesis possible. In particular, the members of my committee have each provided wonderful advice and encouragement throughout this process. My advisor, Dr. Terry Grande has helped shepherd me through this long process and has helped refine and focus my original ideas. Similarly, Dr. Leo Smith has made his tremendous expertise in scorpaenoid fishes available to me from the outset. Drs. Martin Berg and Sushma Reddy have enriched my experience at Loyola both as teachers and as part of my committee. I also wish to thank all my lab mates for their constant support and camaraderie. I am especially grateful to the ever-present Dr. Calvin Borden, who helped me through many of the day to day roadblocks that trouble scientific research.
I would also like to thank the staff of the museums from around the country that agreed to provide the specimens that are the foundation of this work. These include the University of Kansas, the Field Museum, the American Museum, the Museum of Comparative Zoology, the Bishop Museum, and the Smithsonian. An extra debt is owed to Dr. Jeff Daniels of the Smithsonian, whose kindness and generosity allowed for inclusion of many rare specimens.
Vita
Jeremy Harris was born in Philadelphia, Pennsylvania in 1983. From an early age he displayed a great interest in Science. At the University of Chicago, he became fascinated by the concept of evolution and its importance to the structure of biological organisms. After graduating with a BA in 2005, Jeremy worked a number of jobs, including serving as a paramedic on Chicago’s South Side. He resumed his education at Loyola University of Chicago in 2009.
While a graduate student at Loyola, Jeremy continued his interest in evolutionary processes by studying the morphology and function of fishes. Some highlights from these years include presenting his work at the 2011 conference of the American Society of Ichthyologists and Herpetologists. He also discovered a genuine fondness for teaching while working as a TA and as instructor for several introductory biology courses.
Jeremy currently resides in Seattle, Washington where he is earning his PhD and still studying the evolution of fishes.
Committee Members
Dr. Terry Grande (Director)
Dr. Martin Berg
Dr. Sushma Reddy
Dr. Leo Smith (Field Museum)