4th Annual Cal Poly Pomona Student RSCA Conference March 4, 2016 University Library, Oral Presentations from 12:45 to 5 pm Bronco Student Center (Ursa Major), Poster Session, Performance Presentation, and Reception from 4 to 6:30 pm

Lead Author: Sabrina Medrano

Major: Biological Sciences

College: Science

Co-author(s): Not Applicable

Faculty Mentor(s): Dr. Angel Valdes

Presentation Type: Oral Presentation

Project Title: It loves me, it loves me not: Counting species of the "rose petal sea slug," Polybranchia (: ) with a molecular systematics approach.

Synopsis: Molecular study conducted on Polybranchia viridis to identify one or two valid species. Investigation of biogeography of P. virids also conducted.

Abstract: Polybranchia (Gastropoda, , ) is a wide spread pantropical group of herbivorous sea slugs consisting of nine valid species. The biology and the taxonomic relationships of these is poorly studied. Reasons for this include that these animals are easy to overlook because they are hide under rocks or coral rubble during the day suggesting nocturnal behavior. Secondly, the original descriptions describe these species with very similar morphological characteristics making identification very difficult in the field. The objective of this study is to 1) explain the distjunct range of Polybranchia viridis and 2) identify Polybranchia viridis as a valid species or two valid species. The objectives will be tested with the use of three nuclear genes (H3, 18S, 28S) and two mitochondrial genes (CO1 and 16S). A Bayesian analysis will be conducted on nuclear and mitochondrial genes to identify clades and misidentified species. Additionally, the validity of the Eastern Pacific and Caribbean Polybranchia viridis species will be evaluated using scanning electron microscopy to examine the morphology of the radulae and penis (simultaneous hermaphrodites). I expect the distribution pattern of Polybranchia to be explained by vicariant events that date back to the Tethys sea (~200mya). The disjunct range of P. viridis is expected to be a result of the Panama Isthmus that arose 3mya. Consequently, if P.viridis was separated 3mya, then based on genetic and morphology data I hypothesize that there is two valid species.