Redescription and circumscription of the Acuminate Crayfish, Cambarus acuminatus Faxon, 1884 (Decapoda: Cambaridae)

Cambarus acuminatus was described by Walter Faxon in 1884 from three specimens collected from the Saluda River in northwestern South Carolina, USA. Cambarus acuminatus sensu lato has since been acknowledged to comprise a species complex. This complex, also known as Cambarus sp. C, spans a range across much of the Piedmont Plateau and Coastal Plain from central South Carolina north to Maryland and southeastern Pennsylvania. A primary impediment to a much-needed thorough taxonomic assessment and revision of C. sp. C is the absence of taxonomically useful type material of C. acuminatus coupled with the lack of a detailed description of the species. Here we provide a redescription of C. acuminatus based on modern standards for astacoidean crayfishes in the genus Cambarus and emend the circumscription of the species, thereby laying the groundwork necessary for future taxonomic and phylogenetic work within, and involving, the C. sp. C complex.