Distribution and Zoogeography of the Bivalvia of the Eastern Pacific Ocean ? 40 Years Later

GÜLLER, M.; VALENTICH-SCOTT P.; COAN E. V.; ZELAYA, D. G.

Congreso; 87° American Society of Malacology Annual Meeting; 2021

In the early 1980?s, Frank R. Bernard published the first comprehensive check-list of marine bivalvemollusks from the Bering Strait (66oN) to the Cape Horn (60oS). Based on that information, theauthor subsequently revised the distribution and zoogeography of the Bivalvia of the easternPacific Ocean. As part of that study, he recognized four main biogeographic provinces. The aim ofthis study is to reunite the information on bivalves from the eastern Pacific published afterBernard?s contributions and, on the light of this new information: 1) to determine the diversitycurrently known from this area, 2) to update the distributional range for each species, and 3) tore-evaluate the biogeographic scenario previously proposed by Bernard.The main sources of information for this study arise from the three monographs on the bivalveseashells of the western Americas published by the Santa Barbara Museum of Natural History.These contributions provide accurate information on the species occurring from the Beaufort Sea(71oN) to Isla Chiloé (43oS). These monographs were updated with subsequently publishedliterature from this area. Information on the bivalves from Isla Chiloé to Cape Horn comes fromanother monograph (in progress), which includes extensive personal sampling in the region.As part of the present study, a total of 1,234 bivalve species are recognized from the eastern PacificOcean. The numerous papers published after Bernard?s contribution resulted in hundreds ofchanges in the distributional ranges of the species, as well as numerous taxonomic changes. Infact, almost 150 new species were described in the last 40 years from the eastern Pacific Ocean.The biogeographic analysis reveals several similarities to the divisions recognized by Bernard, withthe exception of South America. These results reflect the great recent advances in the knowledgeof the Pacific marine bivalve fauna.