50 Years of Freshwater Bivalves: Shells to DNA

It came as a surprise when I realized I have been working with freshwater bivalves for 50 years. This work has spanned the transition from analyses focused initially on shells, both modern and archaeological, to collaborations using an integrative approach. These 50 years have been broken into four separate periods, each focused on different aspects of freshwater bivalves: Graduate School, University of Tennessee, Knoxville [1973–1980]; Academy of Natural Sciences of Philadelphia [1980–1992]; Consultant [1992–1996]; and North Carolina Museum of Natural Sciences [1996–present]. Starting out, historical literature forced me to pay closer attention to basic taxonomy of the families Unionidae Rafinesque, 1820 and Margaritiferidae Henderson, 1929. When I began, freshwater bivalve research was focused primarily on shell morphology, and with time more comparative anatomy was added along with host fish and behavior to form an integrative approach. The next major shift was the use of starch gel electrophoresis, followed by Sanger sequencing of mitochondrial and nuclear DNA. The introduction of anchored hybrid enrichment using nuclear DNA with an integrative approach is the latest major step forward in the understanding of unionoid evolution. Intensive fieldwork and applying modern techniques in Asia and Southeast Asia has allowed the development of a more robust phylogenetic understanding of the Unionida Rafinesque, 1820. This is a tour of my development as a malacologist and the changing technology applied to taxonomy and systematics, data management, museum collections, and tools to understand this very imperiled group of animals.