https://doi.org/10.11646/zootaxa.4651.1.2 http://zoobank.org/urn:lsid:zoobank.org:pub:546982E1-067E-4963-8066-41F70D518A1F 38 Accepted by J. Goy: 16 May 2019; published: 2 Aug. 2019 Article ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Zootaxa 4651 (1): 038–050 https://www.mapress.com/j/zt/ Copyright © 2019 Magnolia Press Cambarus fetzneri sp. nov., a new species of burrowing crayfish (Decapoda: Cambaridae) from the Allegheny Mountains of Virginia and West Virginia, USA ZACHARY J. LOUGHMAN 1 , STUART A. WELSH 2 & ROGER F. THOMA 3 1 West Liberty University, Department of Natural Sciences and Mathematics, C.S.C Box 139, West Liberty, West Virginia 26074. E-mail:zloughman@westliberty.edu 2 U.S. Geological Survey, West Virginia Cooperative Fish and Wildlife Research Unit, 322 Percival Hall, Morgantown, WV 26506. E-mail: swelsh@mail.wvu.edu 3 Midwest Biodiversity Institute, 4673 Northwest Parkway, Hilliard, Ohio 43026. E-mail: cambarus1@mac.com Abstract The disjunct distribution of Cambarus monongalensis has led to speculation about its taxonomic status. An Appalachian Plateau population occurs in northern and central West Virginia and Southwestern Pennsylvania, and a mountain population occurs in the Allegheny Mountains and Ridge and Valley physiographic provinces of the Virginias. Herein we describe the mountain population as Cambarus fetzneri sp. nov. The two species differ genetically and morphologically, and have different color patterns. Specifically, C. fetzneri sp. nov. chelae lack extensive red coloration on the distal end of the propodus and dactyl, possess rostral margins that lack any red coloration, compared to C. monongalensis, which has extensive red coloration on the dactyl and propodus, as well as red rostral margins. Morphologically, the rostrum of C. fetzneri sp. nov. is shorter and wider than that of C. monongalensis. Also, adult C. fetzneri sp. nov. are considerably smaller in body size than those of C. monongalensis. Key words: Allegheny Mountains, Burrowing Crayfish, Appalachian Mountains Introduction Crayfishes have received considerable attention from biologists since the inception of the current century (Rich- man et al. 2015). The majority of research on this enigmatic group of animals has focused on distributional surveys (Taylor and Schuster 2004; Loughman and Simon 2011), investigations into crayfish ecology (Loughman 2010; Richman et al. 2015), and dedicated species level treatments investigating the conservation standing of imperiled crayfish species (Fetzner and Thoma 2014; Loughman et al. 2015). Crayfish taxonomy and systematics have also received attention, with several new cambarid species described in recent years. Crandall and De Grave (2017) com- pleted a revisionary work focused mainly on genetic differences among crayfish taxa, and subsequently suggested that much of Hobbs (1969) taxonomic suggestion were for the time they were completed based in current science, but not supported using modern technology. Subsequently, using a molecular approach Glon et al. (2018) responded to the phylogeny presented in Crandall and DeGrave (2017), and elevated the burrowing crayfish subgenus Lacu- nicambarus to a full genus. Molecular techniques like those used by Crandall and DeGrave (2017) and Glon et al. (2018) have changed the approach of crayfish systematists, from a taxonomy strictly based on morphology, to one based both on morphology and molecules. Utilization of these technologies is incredibly helpful in untying taxonomic knots within and among populations that demonstrate little to no obvious morphological differences. Utilization of genetics has proven par- ticularly helpful for resolving taxonomic issues with burrowing crayfishes, which display interspecies homoplasic morphologies, given the confines of their burrows, little room for morphological plasticity exists with these species (Foltz et al. 2019; Glon et al. 2018). Many burrowing species in Appalachia, specifically members of the Cambarus dubius Faxon, 1914 complex, Cambarus deweesae Bouchard and Etnier, 1979 complex, and Cambarus monongalensis demonstrate different color phases that are often allied to specific mountain regions and watersheds within the Appalachian Mountains,