Publication Date


Document Type


Committee Members

Daniel Ketcha (Committee Member), Audrey Mcgowin (Advisor), Ioana Sizemore (Committee Member)

Degree Name

Master of Science (MS)


The Ozobranchidae family is the smallest and least studied hirudinean taxon. Our research includes the largest molecular dataset yet reported for marine ozobranchids (Ozobranchus margoi and Ozobranchus branchiatus) with the most number of documented turtle hosts (57) from the Atlantic and Pacific Oceans to date of any marine turtle epibiont study. Turtle species sampled in this study include loggerheads (Caretta caretta), hawksbill (Eretmochelys imbricata), olive ridley (Lepidochelys olivacea), and green turtles (Chelonia mydas). Phylogenetic analyses of mitochondrial (COI) and nuclear ribosomal (18S and 28S) genes all support the monophyly of marine Ozobranchidae leeches with speciation occurring over an extensive period of time, likely prior to the Isthmus of Panama. Histone H3 data suggests at least three histone H3 genes for O. margoi. In addition, mtDNA analyses show higher genetic structure in the Atlantic for O. branchiatus existing in both ocean basins. The small tropical family of turtle annelids was also used to examine the limitations of DNA barcoding on taxa with incomplete taxonomic sampling and to assess whether these issues can be adequately resolved using the character-based approach. The ability to assign ocean basin origin of leech specimens using character-based DNA barcoding suggests the potential for this tool to be integrated with other applications besides species identification.

Page Count


Department or Program

Department of Chemistry

Year Degree Awarded


Included in

Chemistry Commons