Early Evolution of Ligaments and Shell Microstructure in the Bivalvia, with a Comprehensive, Polythetic, Phylogenetic Analysis

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

ABSTRACT Early Evolution of Ligaments and Shell Microstructure in the Bivalvia, with a Comprehensive, Polythetic, Phylogenetic Analysis Dr. Joseph G. Carter, University of North Carolina at Chapel Hill Although ligaments and shell microstructures are important sources of phylogenetic information for the Bivalvia, these features remain poorly known for most early and middle Paleozoic genera and species. The recent discovery of relict aragonitic ligaments and shell microstructures in Ordovician bivalves from Kentucky and in Silurian bivalves from Gotland suggests that these features may be traceable throughout the Phanerozoic. The funded research will develop an extensive database of Paleozoic bivalvian ligament and shell microstructure, focusing on selected Paleozoic faunas representing localities in the United States, Arctic Canada, Sweden, Sardinia, the Czech Republic, China, Australia, New Zealand, and Antarctica. These data will then be combined with other paleontological data and limited inferences of soft anatomy to provide a series of taxonomically comprehensive, rigorously phylogenetic analyses of Paleozoic bivalves based on parsimony, likelihood, and distance methods, tested against stratigraphic data, traditional evolutionary systematics, and modern molecular phylogenies. The final phylogenetic synthesis will be used for a revised phylogenetic classification of Paleozoic bivalves. In addition to clarifying the early evolution of ligaments and shell microstructures, this research will help resolve many outstanding questions of bivalve evolution, and will provide a firm foundation for future phylogenetic analyses of post-Paleozoic bivalves.