Meeting Abstract

P2.101  Tuesday, Jan. 5  Systematics and evolution of Panamic Anachis and related taxa (Neogastropoda: Columbellidae) DEMAINTENON, Marta J.; Univ. of Hawaii, Hilo demainte@hawaii.edu

Columbellid gastropods are a highly diverse group of marine neogastropods, comprising over 600 nominal species worldwide. In the Panamic region, about 45 species are common epibenthic members of intertidal to shallow subtidal communities. Though common, the systematic relationships of these species have never been objectively addressed. The objective of this project, which started during a workshop on the Phylogeny of Neogastropods sponsored by the Smithsonian Institution and hosted by the Smithsonian Tropical Research Institute in 2006, is to investigate the systematics and evolution of the nearshore Panamic columbellid taxa, especially from the genus Anachis and its nominal relatives Costoanachis, Parvanachis, and Glyptanachis. These are among the most diverse of the regional columbellid fauna, comprising about one third of the known Eastern Pacific and Western Atlantic species, and they are largely restricted to the region. Membership in these taxa is presently based primarily on shell sculpture. Results of systematic analysis based on anatomy and morphology suggest revision of the taxonomy of these well-known taxa, though some aspects of the traditional taxonomy are supported. This revisionary work is also being expanded to include western Atlantic taxa as well, such that a more accurate picture of the evolution of this group during closure of the Isthmus of Panama will result.