Summary: | The shortspine spurdog (Squalus mitsukurii) is a putative circumglobal deep-water shark species that was originally described from Japanese waters. Sharks of the genus Squalus are easily misidentified due to the high degree of morphological similarity. We undertook a taxonomic examination of Squalus cf mitsukurii from the Gulf of Mexico (GOM) and found significant morphological and genetic distinctions from the type population in Japan, indicating a new species. We therefore designated a holotype of the species, named Squalus clarkae in honor of Dr. Eugenie Clark. In addition, we assessed population structure of both Squalus clarkae and Squalus cubensis in the Gulf of Mexico and Northwest Atlantic to obtain a clear picture of stock structure in these two species. S. clarkae exhibited weak genetic partitioning between the GOM and Atlantic, though this may be an artifact of low sample sizes in the Atlantic, whereas S. cubensis exhibited strong structure between the Bahamas and sites within the GOM. 2016-06-01 M.S. Department of Biology Masters
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