Cambarus fetzneri sp. nov., a new species of burrowing crayfish (Decapoda: Cambaridae) from the Allegheny Mountains of Virginia and West Virginia, USA.

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.

Lacunicambarus chimera: a new species of burrowing crayfish (Decapoda: Cambaridae) from Illinois, Indiana, Kentucky, and Tennessee.

Lacunicambarus diogenes (Girard 1852) was, until recently, considered to be one of the most widely distributed North American crayfish species, occurring in 31 U.S. States and one Canadian province east of the North American Rocky Mountains. Glon et al. (2018) investigated this claim and found that L. diogenes sensu lato was actually a species complex. The authors redescribed L. diogenes and restricted its range to the Atlantic Coastal Plain and Piedmont ecoregions of eastern North America. In doing so, they also revealed the existence of several probable undescribed species of Lacunicambarus that were previously considered to be L. diogenes. Here, we use morphological and molecular techniques to distinguish and describe one of these species: Lacunicambarus chimera sp. nov., a large primary burrowing crayfish found in parts of the Lower Mississippi, Ohio, Tennessee and Upper Mississippi River Basins. Lacunicambarus chimera is morphologically similar to L. diogenes, from which it can be distinguished by the greater number of spines on the ventrolateral margin of its merus, its wider antennal scale terminating in a short spine, and the presence of a single longitudinal stripe on the dorsal side of its abdomen. We also provide an updated key to Lacunicambarus.

Cambarus (C.) appalachiensis, a new species of crayfish (Decapoda: Cambaridae) from the New River Basin of Virginia and West Virginia, USA.

Cambarus (Cambarus) appalachiensis is a stream-dwelling crayfish endemic to the greater New River basins of Virginia and West Virginia. The new species is morphologically most similar to Cambarus sciotensis. Cambarus appalachiensis can be differentiated from C. sciotensis by its more elongated chelae which possess a single mesial row of tubercles, reduced to no tuberculation on the dorsal-longitudinal ridge of the dactyl, and reduced lateral impression. Cambarus sciotensis has a more subrectangular chelae with two rows of mesial margin tubercles on the chelae, as well as both a pronounced dorsal-longitudinal ridge and pronounced lateral impression. Several chelae meristic ratios also differentiate C. appalachiensis from C. sciotensis. Within the New, Gauley, and lower portions of the Greenbrier basins C. appalachiensis is the dominant tertiary burrowing Cambarus species, and as such, is considered stable across its range.

A case of Appalachian endemism: Revision of the Cambarus robustus complex (Decapoda: Cambaridae) in the Kentucky and Licking River basins of Kentucky, USA, with the description of three new species.

The amazing levels of freshwater biodiversity found in the Appalachian Mountains of the eastern United States are among the highest recorded globally. Localized endemics make up much of this diversity, with numerous fish, freshwater mussels, salamanders and crayfish often being restricted to a single watershed, and in some instances, subwatersheds. Much of this diversity is the product of the processes of vicariance and historical stream drainage patterns. Herein, we describe three new crayfish species, all previously members of the Cambarus robustus complex, which occur in the Appalachian portion of the Kentucky and Licking river basins in Kentucky, USA. All three species differ from each other morphologically, genetically, and zoogeographically, fulfilling the requirements of the integrated species concept. Cambarus guenteri occurs in the southern tributaries of the Kentucky River mainstem as well as throughout the South Fork Kentucky River. Cambarus taylori is a narrow endemic, which only occurs in the Middle Fork Kentucky River. Cambarus hazardi, which has the widest distribution of the three new species, occurs in the North Fork Kentucky River, Red River, and upper reaches of the Licking River basin. Stream piracy events between the Cumberland and South Fork Kentucky River, as well as the Licking, Red and North Fork Kentucky rivers, are theorized to be important in the evolution of this complex. Cambarus guenteri is proposed as currently stable, though both C. taylori and C. hazardi are considered imperiled at this time due to habitat destruction throughout both of their respective ranges.

Cambarus (Jugicambarus) adustus, a new species of crayfish from northeastern Kentucky delimited from the Cambarus (J.) aff. dubius species complex.

A new species of burrowing crayfish, Cambarus (Jugicambarus) adustus, is described from Lewis County in northeastern Kentucky, USA. The new species is most similar morphologically to C. dubius. Cambarus adustus coloration differs from C. dubius by lacking red, orange and blue hues, and instead is brown over the entire body surface. Morphological differences between C. dubius and C. adustus exist in the form I male gonopod, with C. adustus possessing a caudal knob, while C. dubius does not. In addition, the lateral carapace of C. adustus is distinctly tuberculate, whereas in C. dubius the carapace lacks extensive tuberculation. Cambarus (J.) adustus appears to have an extremely small geographic range (~19.5 km2), and as such we suggest its consideration for both state and federal levels of protection.

Cambarus (Jugicambarus) pauleyi, a new species of crayfish (Decapoda: Cambaridae) endemic to southcentral West Virginia, USA, with a re-description of Cambarus (J.) dubius.

Cambarus (Jugicambarus) dubius Faxon, 1884 is a polychromatic montane burrowing crayfish with a long, turbulent taxonomic history since its original description by Walter Faxon in 1884. Over the years, many distinct color phases have been identified, with the majority of these being confined to a specific geographic or physiographic region in the central and southern Appalachians. Previous investigations of this species (e.g., Dewees 1972) were unable to discover consistent morphological differences among the various groups, and thus were unable to clarify what has long been considered a species complex. Due to lingering taxonomic issues, we herein re-describe, delimit and restrict the concept of C. dubius. We also describe a new species, Cambarus (Jugicambarus) pauleyi, from the same complex, which can be identified through the use of geographic distribution, coloration, and distinct morphological characters. Cambarus dubius sensu stricto, as defined here, is restricted to the "typical form" which has an overall orang-ish color pattern on the dorsal and lateral sides, with cream ventrally. The distribution of C. dubius s.s. is limited to the central and northern portions of the Allegheny Mountains and high elevations of the Appalachian Plateau in central West Virginia, western Maryland, and southcentral Pennsylvania. In contrast, C. pauleyi is endemic to high elevation wetlands (>700 m) in the Meadow and Greenbrier River basins in Greenbrier and Monroe counties, West Virginia. Cambarus pauleyi can be differentiated from C. dubius s.s. by 1) its blue dorsal coloration compared to the orange coloration of C. dubius s.s., 2) its large (palm depth/(palm length) ratio, and 3) its smaller (rostral width)/(rostral length) ratio. Cambarus pauleyi can be separated from other peripatric populations of C. dubius sensu lato that occur in the Meadow and Greenbrier River drainage by its 1) blue coloration compared to the orange and black coloration of the latter, 2) the smaller (palm depth)/(palm length) ratio in C. pauleyi, and 3) the deeply excavated rostrum of C. dubius compared to the moderately excavated rostrum of C. pauleyi. Cambarus pauleyi can be easily differentiated from both taxa by the presence of two subpalmer tubercles. Both C. dubius s.s and peripatric C. dubius lack subpalmer tubercles. Cambarus pauleyi has an extremely narrow geographic distribution and has possibly experienced a significant range reduction due to the conversion of wetlands into pastures, and should be considered "Endangered" according to American Fisheries Society listing criteria (Taylor et al. 2007).

Multiple drivers of decline in the global status of freshwater crayfish (Decapoda: Astacidea).

Rates of biodiversity loss are higher in freshwater ecosystems than in most terrestrial or marine ecosystems, making freshwater conservation a priority. However, prioritization methods are impeded by insufficient knowledge on the distribution and conservation status of freshwater taxa, particularly invertebrates. We evaluated the extinction risk of the world's 590 freshwater crayfish species using the IUCN Categories and Criteria and found 32% of all species are threatened with extinction. The level of extinction risk differed between families, with proportionally more threatened species in the Parastacidae and Astacidae than in the Cambaridae. Four described species were Extinct and 21% were assessed as Data Deficient. There was geographical variation in the dominant threats affecting the main centres of crayfish diversity. The majority of threatened US and Mexican species face threats associated with urban development, pollution, damming and water management. Conversely, the majority of Australian threatened species are affected by climate change, harvesting, agriculture and invasive species. Only a small proportion of crayfish are found within the boundaries of protected areas, suggesting that alternative means of long-term protection will be required. Our study highlights many of the significant challenges yet to come for freshwater biodiversity unless conservation planning shifts from a reactive to proactive approach.

Cambarus (Puncticambarus) callainus, a new species of crayfish (Decapoda: Cambaridae) from the Big Sandy River basin in Kentucky, Virginia, and West Virginia, USA.

Cambarus (Puncticambarus) callainus, new species, is a stream-dwelling crayfish endemic to the Big Sandy River basin in Kentucky, Virginia, and West Virginia. Within the basin, C. callainus occurs in the Levisa, Tug, and Russell fork watersheds. The new species is morphologically and genetically most similar to Cambarus veteranus, which is endemic to the Upper Guyandotte River basin of West Virginia. The new species can be differentiated from C. veteranus by its more lanceolate rostrum (width less than 50% length), slightly more obtuse suborbital angle, and less well-defined lateral impression at the base of the chelae. 

Cambarus (C.) hatfieldi, a new species of crayfish (Decapoda:Cambaridae) from the Tug Fork River Basin of Kentucky, Virginia and West Virginia, USA.

Cambarus (Cambarus) hatfieldi is a stream-dwelling crayfish that appears to be endemic to the Tug Fork River system of West Virginia, Virginia, and Kentucky. Within this region, it is prevalent in all major tributaries in the basin as well as the Tug Fork River's mainstem. The new species is morphologically most similar to Cambarus sciotensis and Cambarus angularis. It can be differentiated from C. sciotensis by its squamous, subtrinagular chelae compared to the elongate triangular chelae of C. sciotensis; its shorter palm length/palm depth ratio (1.9) compared to C. sciotensis (2.3); and a smaller areola length/total carapace length ratio (30.4% vs.36.5% respectively). Cambarus hatfieldi can be differentiated from C. angularis by its smaller areola length/total carapace length ratio (30.4% vs. 36.7% respectively); a smaller rostrum width/rostral length ratio (59.4% vs. 67.2% respectively); its rounded abdominal pleura as compared to the subtruncated pleura of C. angularis; the length of the central projection and mesial process of C. hatfieldi which both extend to the margin of the gonopod shaft or slightly beyond the margin compared to the central projection of C. sciotensis and C. angularis where both extend well beyond the margin of the gonopod shaft.