An integrative taxonomic assessment leads to the synonymy of the Waccamaw Crayfish Procambarus braswelli Cooper 1998 with the Cedar Creek Crayfish Procambarus chacei Hobbs 1958 (Decapoda: Cambaridae)

The southeastern United States (U.S.) is a global hotspot for crayfish diversity, with the majority of the >350 species known in the U.S. occurring here. Crayfishes in the genus Procambarus are common in lower gradient lotic and lentic systems of the southeast, but from both a taxonomic and systematic perspective, this genus is largely neglected in comparison to other crayfish genera. The aim of this study is to clarify the taxonomic status of two conservation priority crayfishes from the southeastern U.S. by testing the hypothesis that Procambarus braswelli Cooper, 1998 and Procambarus chacei Hobbs, 1958 are distinct species. We conducted a geometric morphometric analysis of these species, including 16 morphological metrics across 51 specimens throughout the ranges of these species in North Carolina and South Carolina. We then isolated, extracted, and sequenced a fragment of the COI gene and used maximum likelihood phylogenetic analysis to determine genetic distinctness. Results of multivariate analyses show overlapping morphologies between species and genetic structure that does not co-vary with original species determinations. Together, the available morphological and genetic information indicates that P. chacei and P. braswelli be synonymized. Additional taxonomic, life history, and ecological work is sorely needed for Procambarus crayfishes of the species-rich southeastern U.S.