A National Science Foundation grantee, Reynolds is an expert on marine invertebrate biology, particularly the evolution of Mollusca -- the phylum that includes snails, clams and squid. He has worked with biology student research assistants on cruises and at marine field stations along both coasts of North America and in Antarctica.
His recent publications have appeared in Advances in Marine Biology, Zoological Journal of the Linnean Society, and in Molecular systematics and phylogeography of mollusks (Smithsonian Institution Press). He is also the editor of Invertebrate Biology, an international journal of the American Microscopical Society. Reynolds has been a visiting scientist at the Smithsonian Marine Station in Caribo Cay, Belize, the National Museum of Natural History, and the Natural History Museum in London.