71.4 Friday, Jan. 6 Cryptic species diversity in the marine pulmonate limpet subgenus Siphonaria (Heterosiphonaria) in the vicinity of the Gulf of California EERNISSE, D.J.*; KVIST, S.; BARRIO, A.; SIDDALL, M.E.; California State Univ. Fullerton; American Museum of Natural History, New York; American Museum of Natural History, New York; American Museum of Natural History, New York email@example.com
Marine pulmonate “false” or “siphon” limpets (Siphonaria spp.) are among the most common and ecologically important tropical eastern Pacific rocky shore gastropods, yet they have been little studied and identification to species is challenging. We were able to study siphon limpets collected during a 2004 Sea of Cortez expedition as supplemented by some additional samples from between Baja California Sur and Manzanillo, Mexico. The subgenus Heterosiphonaria Hubendick 1945 has been used for all Panamic species, and is considered restricted to between Baja California Sur and Peru in the tropical Eastern Pacific. Given confusing morphological variation, we undertook a DNA sequencing approach, employing combined analysis of mitochondrial 16S and COI gene regions. This revealed at least five discrete groupings, each with strong bootstrap support. In contrast, only three species are currently recognized from this region, not including the more southern and morphologically distinctive “giant siphon limpet,” S. gigas. Some of our discrete clades appear to be Gulf of California endemics that do not correspond to any the about 11 total nominal species, including junior synonyms, proposed to date. Our results either imply unrecognized species diversity or strong phylogeographic structure. Inclusion of available GenBank Siphonariidae 16S/COI sequences supported the robust monophyly of tropical Eastern Pacific species, exclusive of other worldwide Siphonariidae. This partly corroborates the Heterosiphonaria grouping, which was proposed from genitalia affinities, but sequences for the Heterosiphonaria type species, S. gigas, are still lacking.