Two new species of freshwater crayfish of the genus Faxonius (Decapoda: Cambaridae) from the Ozark Highlands of Arkansas and Missouri.

Two new species of freshwater crayfish are described from the Ozarks Plateau of northern Arkansas and southern Missouri. Both species are restricted to the mainstem of rocky streams that are at least fourth-order or greater in size. Recent genetic and morphological investigations of the coldwater crayfish, Faxonius eupunctus Williams, 1952, indicated that it was actually composed of several undescribed species. Faxonius eupunctus is herein restricted to just the Eleven Point River system. Faxonius roberti, new species is found in the mainstem of the Spring and Strawberry river systems in northern Arkansas. It differs from F. eupunctus by lacking a male Form-I gonopod with a distal spatulate mesial process, and presence of two spines on the dorsal side of the merus, where F. eupunctus typically has 1 spine. Faxonius wagneri, new species is known from a 54 mile (86 km) stretch of the Eleven Point River mainstem, ranging from just southeast of Greer, Missouri to just north of Birdell, Arkansas. Faxonius wagneri can be differentiated from both F. eupunctus and Faxonius roberti sp. nov. by using the male Form-I and Form-II gonopods, the shape of the chelae, and the female annulus ventralis. In F. wagneri, the terminal elements of the first pleopod are almost twice as long as those in F. eupunctus and F. roberti, with the tips of the appendage reaching the posterior base of the first perieopod when the abdomen is flexed forward, whereas, in the other two species, these elements only reach the base of the second pereiopod. The species also possesses two spines on the dorsal side of the merus of the first pereiopod, which helps distinguish it from F. eupunctus.

Phylogenetic evidence from freshwater crayfishes that cave adaptation is not an evolutionary dead-end.

Caves are perceived as isolated, extreme habitats with a uniquely specialized biota, which long ago led to the idea that caves are "evolutionary dead-ends." This implies that cave-adapted taxa may be doomed for extinction before they can diversify or transition to a more stable state. However, this hypothesis has not been explicitly tested in a phylogenetic framework with multiple independently evolved cave-dwelling groups. Here, we use the freshwater crayfish, a group with dozens of cave-dwelling species in multiple lineages, as a system to test this hypothesis. We consider historical patterns of lineage diversification and habitat transition as well as current patterns of geographic range size. We find that while cave-dwelling lineages have small relative range sizes and rarely transition back to the surface, they exhibit remarkably similar diversification patterns to those of other habitat types and appear to be able to maintain a diversity of lineages through time. This suggests that cave adaptation is not a "dead-end" for freshwater crayfish, which has positive implications for our understanding of biodiversity and conservation in cave habitats.

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).

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. 

Hylid frog phylogeny and sampling strategies for speciose clades.

How should characters and taxa be sampled to resolve efficiently the phylogeny of ancient and highly speciose groups? We addressed this question empirically in the treefrog family Hylidae, which contains > 800 species and may be nonmonophyletic with respect to other anuran families. We sampled 81 species (54 hylids and 27 outgroups) for two mitochondrial genes (12S, ND1), two nuclear genes (POMC, c-myc), and morphology (144 characters) in an attempt to resolve higher-level relationships. We then added 117 taxa to the combined data set, many of which were sampled for only one gene (12S). Despite the relative incompleteness of the majority of taxa, the resulting trees placed all taxa in the expected higher-level clades with strong support, despite some taxa being > 90% incomplete. Furthermore, we found no relationship between the completeness of a taxon and the support (parsimony bootstrap or Bayesian posterior probabilities) for its localized placement on the tree. Separate analysis of the data set with the most taxa (12S) gives a somewhat problematic estimate of higher-level relationships, suggesting that data sets scored only for some taxa (ND1, nuclear genes, morphology) are important in determining the outcome of the combined analysis. The results show that hemiphractine hylids are not closely related to other hylids and should be recognized as a distinct family. They also show that the speciose genus Hyla is polyphyletic, but that its species can be arranged into three monophyletic genera. A new classification of hylid frogs is proposed. Several potentially misleading signals in the morphological data are discussed.

Linear habitats and the nested clade analysis: an empirical evaluation of geographic versus river distances using an Ozark crayfish (Decapoda: Cambaridae).

The nested clade analysis can be extremely useful in testing for an association between genetic variation and geography and in explaining these observed patterns in terms of historical or contemporary population processes. The strength of this method lies in its ability to test a variety of processes simultaneously under a rigorous statistical framework. Indeed, many recent studies have used the nested analysis in a wide range of terrestrial and aquatic taxa. However, it has been suggested that riverine, riparian, or coastal species may be better examined using river (or coastal) distances rather than the standard geographic (great circle) distances among populations. It is thought that the standard geographic distances may not adequately describe the actual distances involved between populations of species inhabiting these one-dimensional (riverine) habitats. Therefore, we analyzed population data from an Ozark crayfish, Orconectes lutetus, to examine the effects on the results of a nested clade analysis using river distances. In most cases, the haplotypes detected in this crayfish were unique to a particular drainage or a group of neighboring drainages, indicating very little movement of individuals among drainages. Five major population groups were detected, corresponding to many of the major river drainages sampled in this study. The two types of distance analyses obtain similar results for higher-level (older) clades, but differ in many of the inferences made for lower-level (younger) clades. However, we suggest that the comparison of both types of analyses for riverine species may enhance the process of elucidating historical and contemporary population processes, especially in cases where the transfer of individuals among different drainages are involved.