Diversity and evolutionary history of fossil crayfishes

Abstract

Abstract Freshwater crayfishes are among the most successful freshwater animals and are quite important for society economically, ecologically, and culturally. Since crayfishes are almost exclusively restricted to freshwater, their dispersion potential is much lower than that of marine crustaceans. Their biogeographic distribution is thus the result of a still poorly known long and complex evolutionary history. Most of the efforts made to untangle this history have worked from the distribution of extant crayfishes and their phylogenetic relationships, seldom using the fossil record. We here review the state of our current published knowledge on the fossil record of crayfishes, from their fossilized bodies and burrows. We review the Late Triassic Enoploclytia porteriMiller & Ash, 1988, one of the oldest crayfish body fossils, and show it is most likely a freshwater crayfish and assigned mistakenly to a marine genus. We also discuss burrows from Argentina, suggesting they are actually insect burrows, and burrows and an isolated claw from Libya, which we herein interpret as most likely from brachyuran crabs. We list a total of 65 occurrences or groups of occurrences from across the world and from the Late Devonian to Pleistocene fossils. This long history strengthens the current hypothesis that crayfishes inhabited Pangea and diversified partly via vicariance due to Pangea’s breakup during the Mesozoic and into the Cenozoic. Our review also highlights the importance of fossil burrows and body fossils to understand modern faunas and the importance of taxonomic revision of fossil taxa.