Cryptic Speciation in the Tropical Atlantic brittle genus Ophioderma

Emily Rose Sharkey

Authors:  Emily Rose Sharkey, Tania Pineda-Enriquez, Dr. Gustav Paulay

Faculty Mentor: Dr. Gustav Paulay

College: Florida Museum of Natural History


Marine diversity and speciation remain poorly understood, even in such large, colorful, and relatively well-known groups as brittle stars. Genetic studies have demonstrated that species that were thought to be well-understood as delineated by morphology are often complexes of cryptic species. DNA barcoding is a useful tool to guide species delineation and to highlight characters for distinguishing species, such as coloration, life-history traits, and habits. We tested for potential cryptic diversity in one of the most abundant, large, colorful, and diverse genera of Caribbean brittle stars, Ophioderma. Cytochrome Oxidase I sequences were obtained for numerous specimens of O. appressa, O. brevispina, O. brevicauda, O. cinerea, O. rubicunda, O. phoenia, O. guttata and O. squamosissima from different localities across the tropical western Atlantic, from the Florida Museum of Natural History collections. Results revealed 15 distinct Molecular Operational Taxonomic Units (MOTUs) among these 8 species, indicating substantial unrecognized, cryptic diversity in the genus. We are now sequencing additional markers (16S and ITS) to further assess the status of these MOTUs.

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