Assessing phylogenetic placement of an undocumented red-burrowing crayfish in the Tennessee River

Abstract

Crayfishes are a diverse freshwater group of crustaceans with over 450 species found in North America. This diversity is likely an underrepresentation given that many species are continually being described and several species represent species complexes. A particularly underrepresented group of crayfishes are within the burrowing species. Their burrowing behavior complicates sample collecting and many studies and surveys inaccurately portray community diversity. As a result, there are many undescribed taxa within burrowing crayfish. Investigators at the Tennessee Valley Authority discovered a previously undocumented red-burrowing crayfish within the middle Tennessee River watershed in Moore County, Tennessee. To assess the evolutionary and systematic placement of this novel taxa, we sequenced the mitochondrial COI and 16s genes and compared them to the Genbank and tissue sequences of morphologically similar species and subspecies. Our phylogenetic tree analyses identified members of the Cambarus striatus species complex from nearby areas as a sister clade to the red burrower and indicated strong support for the novel red burrower to represent a distinct evolutionary lineage. Future analyses of nuclear single nucleotide polymorphisms (SNPs) will provide a better depiction of where the novel red burrower lies in its respective phylogeny as well as delineate the genetic boundary between the red burrower and members of the Cambarus striatus species complex.