The use of color photographs in crayfish species descriptions, state faunal books and popular articles is relatively recent. Except for verbal color descriptions, color and color patterns have not often been explored by crayfish researchers. Carotenoids and carotenoproteins are responsible for much of the color found in the integument and exoskeleton of crayfishes and other crustaceans. Research has shown variation in color may be the result of the environment, diet, molt stage and age, genetics, or a combination of these. Crayfishes possess color vision, may use polarization vision, and have the possibility of fluorescent vision. They also have very good low light vision. Crayfishes have a multichromatic range in color sensitivity; it ranges from blue to red, with no UV sensitivity. Color vision may be an important factor in intraspecific and interspecific competition, territoriality, camouflage, sexual selection, and communication. A distinction is made between base or background colors displayed in crayfishes and their exhibited color patterns. While actual base or background colors may vary among individual crayfishes, a case is made that color patterns show much less intraspecific variation. Distinct color patterns are the result of highly contrasting colors on appendages or parts of appendages such as chelae, leg joints, tail fan, spines, and tubercles. Body regions like the carapace and abdomen may also have contrasting spots, bands or stripes. Color patterns may be useful in better understanding crayfish taxonomy, phylogeny, and evolutionary convergence, and examples are provided.

While sampling for the Rusty Gravedigger, Lacunicambarus miltus, Taylor et al. (2011) found one or more potentially undescribed burrowing crayfish species in the genus Lacunicambarus inhabiting the area between the Pascagoula River and Mobile Bay in southern Alabama and Mississippi. Molecular analyses by Glon et al. (2018) confirmed that samples from this area were genetically distinct from other Lacunicambarus crayfishes. These findings prompted a dedicated sampling trip in January 2020. We used morphological and molecular analyses to investigate the specimens we collected and, based on our results, we describe two new crayfish species: the Lonesome Gravedigger, L. mobilensis sp. nov. and the Banded Mudbug, L. freudensteini sp. nov. Lacunicambarus mobilensis sp. nov. is sister to the Rusty Gravedigger, L. miltus, while L. freudensteini sp. nov. is sister to the Painted Devil Crayfish, L. ludovicianus. Both new species are currently known from a small number of sites in southern Alabama and Mississippi and may require conservation attention. In addition, we provide an updated key to Lacunicambarus crayfishes that includes these new species.

Kentucky's crayfish faunal list has undergone considerable changes since the publication of Crayfishes of Kentucky (Taylor and Schuster, 2004). We conducted an in-depth literature review and reviewed collection databases to develop an up-to-date checklist of crayfish species known to occur in Kentucky. Sixty-five crayfish species have been documented from Kentucky to date, including twelve new species described and three state records since 2004. One new species description (Faxonius sp. A. nov. sp.) is currently underway and was included in the species list for future reference. Additionally, we provide information on changes in crayfish taxonomy, crayfish species that may occur in Kentucky, and potential cryptic species where additional research may result in new species being detected. We hope this information provides clarity for researchers and resource managers and encourages additional crayfish research in Kentucky.

Faxonius barrenensis (Rhoades, 1944) is endemic to the Green River system of Kentucky and Tennessee, USA and closely related to Faxonius mirus (Ortmann, 1931), which is restricted to Tennessee River tributaries in Tennessee and Alabama. A crayfish with morphological affinities to these species (Faxonius sp.) occurs in the Red River system (Cumberland River Drainage) of Kentucky and Tennessee. Whether the latter represents a disjunct population of F. barrenensis, F. mirus, or a distinct species, has not been tested. Whether the shared morphological traits reflect shared ancestry or convergence is unknown. We used molecular and morphological data, including two mitochondrial (COI and 16S) and two nuclear (28S and GAPDH) genes and a standard suite of phenotypic measurements to examine the phylogenetic relationships and the taxonomic status of Faxonius sp., relative to F. barrenensis, F. mirus, and other species of FaxoniusOrtmann, 1905. All gene datasets recovered focal taxa as a clade, implying their morphological similarities likely reflect shared ancestry. In all mitochondrial and combined gene trees, Faxonius sp. was recovered as genetically divergent from F. barrenensis and F. mirus. Faxonius sp. is phenotypically distinguished from F. barrenensis and F. mirus based on several characteristics including shorter rostrum, longer abdomen, wider areola, and straight margins on both mandibles (toothed in F. mirus; toothed and straight in F. barrenensis); Form I males have a strong angular shoulder on the gonopod, in comparison to F. barrenensis. Given these findings, we describe Faxonius sp. as Faxonius bellatorn. sp. Faxonius bellatorn. sp. has been collected at only four localities, suggesting it has a small range and warrants conservation concern.

Ongoing changes in climate are expected to alter current species’ habitat and potentially result in shifts in species distributions. While climatic conditions are important to a species’ ability to persist in an area, for many taxa, other environmental factors, such as geology, land cover, and topography, are also important for providing suitable habitat. Furthermore, aquatic species experience changes in climatic conditions through the effect precipitation and air temperature have on streamflow regimes and water temperature. In this study, species distribution models (SDMs) for ten stream-dwelling crayfish species were generated using a maximum entropy approach across the Mobile River Basin in the southeastern United States. SDMs were developed using model-generated contemporary estimates of streamflow and water temperature as well as geologic, topographic, and land cover data. Future distributions were then projected using global climate model (GCM) projections of streamflow and water temperature. Geology, topography, and streamflow appear to be more important predictors of suitable habitat than water temperature for crayfish species within the Mobile River Basin. Species distributions regulated by limited influences from stream flow and water temperature displayed relatively small changes in projected future habitat distributions based on various GCM scenarios. When shifts in species distributions were projected into the future, these shifts did not appear to follow a northward retreat or expansion, likely due to the limited impact of water temperature on the modeled distributions of suitable habitat for these species. Furthermore, species’ habitat distribution responses among future climate scenarios were variable within and among species and did not vary unidirectionally with increased severity of climate change as realized through increased warming patterns.

Cambarellus (Pandicambarus) rotatus, new species, is a dwarf crayfish from floodplain swamps in the Tombigbee and Black Warrior river drainages of Greene, Hale, and Marengo counties, Alabama. The new species is morphologically most similar to Cambarellus (Pandicambarus) lesliei. They differ in a several morphological characters. Cambarellus rotatus, new species, has gonopods that are rotated mesially so that the terminal elements oppose each other, and they have a short C-shaped sperm groove. These are unique features among known species of Cambarellus.

The crayfish subgenus Procericambarus (genus Orconectes) found in the Eastern Highlands of the United States represents a rich assemblage of stream-dwelling macroinvertebrates. While the taxonomic status and distribution of its members were clarified in a previous study, newly diagnosed characters and newly collected specimens warranted a revision to previous hypotheses of Procericambarus membership in the southeastern United States. Using morphological characters, we describe herein a new species of crayfish occurring in the Tennessee River drainage of northern Alabama and southwestern Tennessee. We also provide a revised key for the identification of members of O. juvenilis Species Complex.

Cambarus (Depressicambarus) clairitae, new species, is an epigean crayfish from two drainages of the Locust Fork system in Blount and Jefferson counties, Alabama. It belongs to the halli Group in the subgenus Depressicambarus. The new species is morphologically most similar to Cambarus (Depressicambarus) englishi. They differ in a several morphological characters. Cambarus englishi has a more strongly recurved central projection, a wider areola, and a more distinct and set off rostral acumen than the new species. It also has light gray to white antennae while the antennae of the new species are brown. In addition to the description of the new species, the halli Group in Alabama is discussed.

Abstract As part of a study of aquatic faunal community changes along riverine-lacustrine transition zones upstream of Lewis Smith Reservoir in northwest Alabama, USA, we collected crayfish from 60 sites in the Sipsey Fork, Brushy Creek, and selected tributaries (Black Warrior River system). After finding two unexpected and possibly-introduced crayfish species, we expanded our investigation of crayfish distributions to include crayfish obtained from stomachs of black bass (Micropterus spp.) caught at seven sites in the reservoir. To explore what crayfish species were in the drainage historically, we examined museum databases as well as stomach and intestinal contents of a variety of preserved fishes that were caught in the Sipsey Fork and Brushy Creek drainages upstream of the reservoir in the early 1990’s. Of the seven crayfish species collected, one, Orconectes (Procericambarus) sp. nr ronaldi, was not previously reported from Alabama, and another, O. lancifer, was not reported from the Black Warrior River system prior to the study. Three are known or possibly introduced species. Upstream of the reservoir, the native species Cambarus obstipus, C. striatus, and O. validus were common. The same three species were found in fish collected in the 1990’s. Orconectes perfectus was found only in the reservoir but may be native to the drainage. Orconectes lancifer was in the reservoir and in stream reaches influenced by the reservoir. Evidence points to O. lancifer being introduced in the drainage, but this is uncertain. Orconectes sp. nr ronaldi was found in a relatively small portion of Brushy Creek and its tributaries, in both flowing and impounded habitats, and may be introduced. Orconectes virilis is introduced in Alabama and was found only in stomachs of fish collected in the reservoir.

Procambarus (Girardiella) holifieldi, new species, is a primary burrowing crayfish from a low-lying field in Perry County, Alabama. It belongs to the Hagenianus Group in the subgenus Girardiella. The new species is morphologically most similar to Procambarus (Girardiella) barbiger. They differ in the size and shape of the caudal processes. Procambarus barbiger has a beard along the mesial margin of the palm of the chela, while the new species lacks the beard. In addition to the description of the new species, the Hagenianus Group is reviewed and new synonymies are provided. We demonstrate that a cephalic process is indeed present in the Hagenianus Group.

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.

Over seventy percent of the world's freshwater crayfish species are found within the United States, and much of this diversity is concentrated in the southeastern United States. Yet many of these species remain understudied. Of particular interest is the conservation status of these understudied taxa. We conducted fieldwork in 2011 across northeastern Alabama and northwestern Georgia to review the occurrence, habitat, and in sonic cases, local population densities of three crayfish species (Cambarus scotti, C. unestami, and C. cracens) to determine current distributions in relation to historical surveys. All three species occur in flowing small to medium-sized streams with firm substrates of gravel, cobble, and bedrock. Two species (C. scotti and C. unestami) have stable populations, occurring at 79% and 90% of sites surveyed, respectively. In contrast, surveys for the third crayfish species (C. cracens) indicated a need for conservation action, with this species occurring at a single site.

Diagnosable taxonomic units are fundamental to conservation biology and management of resources and the need for sound science in both fields is more pressing for aquatic ecosystems. Within freshwater crayfishes, the North American genus Orconectes is one of the most diverse in the World. Accurate assessments of species level relationships and species boundaries within the genus have historically been hampered by a low number of variable morphological characters and inadequate sampling from across the ranges of many taxa. We examine a diverse group of southeastern United States stream dwelling Orconectes in the subgenus Trisellescens using 16S, COI mtDNA, and morphology to resolve uncertainties in species boundaries. Our results suggest that strong divergences exist between taxa found above and below the Fall Line in parts of the southeastern United States and the taxonomy for taxa found in that region should remain unchanged. However, using both molecular and morphological datasets we are unable to determine species limits for some taxa found on and below the Fall Line. Analysis of DNA data suggests that historical and ongoing genetic events such as gene introgression may contribute to these uncertainties. For taxa found on and below the Fall Line, we suggest tentative, taxonomic assignments. Finally, we argue for increased sampling of independent molecular datasets and increased sample sizes for all cambarid crayfish biogeographic studies.

The southeastern United States contains ca. 250 species of crayfish. Of these, 85 are historically known from Alabama. Previous studies have shown that the Sipsey River drainage in western Alabama is a diversity "hotspot" for freshwater mussels (42 spp.) and fishes (102 spp.). This is attributed to diverse geologic features, an intact flood-plain, lack of impoundments, and lack of urban centers. Intensive sampling of the Sipsey River drainage over a 2-year period resulted in a collection of 294 crayfish representing 12 species. Three of these species, Cambarus ludovicianus, Orconectes chickasawae, and Procambarus vioscai paynei are of conservation concern. Our results indicate that the Sipsey River harbors a greater richness of crayfish species per area than other drainages surveyed to date in Alabama.

Distributional records for 293 caddisfly species representing 22 families and 68 genera are reported from Kentucky along with information on taxonomy, flight period, habitat, and conservation status. Sixty-nine species represent new records for the Commonwealth. Kentucky's geographic regions are compared with respect to species richness. Distributions are summarized for all species; detailed occurrence data are provided for new records, species with limited distributions, and those representing substantial range extensions. A total of 69 species (24% of the fauna) are identified as imperiled or vulnerable within Kentucky.

Cambarus (Lacunicambarus) miltus (Rusty Gravedigger Crayfish) is a primary burrowing crayfish known from a limited portion of the Gulf Coastal region of the United States. The lack of form I males in collections has in the past prevented species-level identifications and hampered conservation reviews. We conducted an intensive status survey for C. miltus during 2007 and 2008. Our results suggest that the species is much more widespread than previously known and that conservation attention is unwarranted. Preferred habitat for the species is ephemerally flooded and thinly wooded floodplains of small streams and swamps.