The deep channels of large rivers throughout the humid Neotropics are occupied by diverse and abundant assemblages of electric knifefishes. Historically this habitat has been poorly sampled, but extensive benthic trawling efforts in the Brazilian Amazon in the 1990s produced large numbers of electric fishes especially in the family Apteronotidae. A large number of these specimens, initially identified as Porotergus, have been found to belong within Compsaraia, a genus with two species described from the Orinoco and western Amazon. From this material we describe a new species, from the Amazon River in Brazil, and provide a new diagnosis for the genus. This species is readily distinguished from congeners by a short, rounded snout and small, subterminal mouth with reduced dentition. This species inhabits large rivers in the Eastern and Central Amazon between Ilha Grande de Gurupá and the mouth of the Rio Içá. This description brings the total number of valid apteronotid species to 95.

The Red-eyed Coquí, Eleutherodactylus antillensis, is a terrestrial frog endemic to the Puerto Rican Bank (Puerto Rico and numerous islands and cays off its eastern coast), in the eastern Caribbean Sea. The species was likely introduced in Saint Croix, an island c. 100 km southeast of Puerto Rico, in the late 1930s, and in Panamá City, Panamá, in the late 1950s or early 1960s, but the source(s) of these introductions are unknown. We analyzed sequence data from one mtDNA locus and four nuDNA introns to infer the origin(s) of the Saint Croix and Panamá City populations and quantify their genetic diversity. Saint Croix and Panamanian populations do not share any haplotypes, and they cluster with different native populations, suggesting that they are derived from separate sources in the Puerto Rican Bank. Patterns of population structure trace the probable sources of E. antillensis in Saint Croix to islands off Puerto Rico's eastern coast, which include Vieques, Culebra, Saint Thomas, Saint John, Tortola, and Virgin Gorda, and possibly to eastern Puerto Rico as well. In contrast, Panamá City E. antillensis probably originated from either western or eastern Puerto Rico. Genetic diversity in the introduced populations is similar to or lower than in populations in the species' native range, indicating that genetic diversity has not increased in the alien frogs. Our findings may facilitate the development of preventive measures to minimize introductions of non-native amphibians in the Caribbean and Central America.

Tandanus bellingerensis, new species, is described based on specimens from four river drainages (Bellinger, Macleay, Hastings, and Manning rivers) of the mid-northern coast of New South Wales, Australia. Previously, three species were recognized in the genus Tandanus: T. tropicanus of the wet tropics region of northeast Queensland, T. tandanus of the Murray-Darling drainage and coastal streams of central-southern Queensland and New South Wales, and T. bostocki of southwestern Western Australia. The new species is distinguished from all congeners by a combination of the following morphologic characters: a high count of rays in the continuous caudodorsal and anal fins (range 153–169, mode 159), a high count of gill rakers on the first arch (range 35–39, mode 36), and strongly recurved posterior serrae of the pectoral-fin spine. Additionally, results from previously conducted genetic studies corroborate morphologic and taxonomic distinctness of the new species.

Both abiotic and biotic factors influence population and community structure. However, the simultaneous assessment of the relative importance of both types of factors is rarely performed for multiple traits of a population, such as body size and abundance. Comparisons among different demographic rates are necessary for teasing apart the importance of species interactions and/or environmental conditions on both population and community structure. We tested whether biotic (e.g., larval competition) or abiotic factors influenced larval salamander density and body size in natural populations of two known salamander competitors, Ambystoma talpoideum and A. maculatum. Over six years, we surveyed 33 ponds where these species co-occur in western Kentucky, USA. We found that larval densities between species were positively correlated, and that habitat features had contrasting, species-specific effects. Larval sizes for each species showed negative intra- and interspecific relationships with larval densities of each species, but larval A. maculatum generally exerted the stronger relative interspecific effect. Overall, our study highlights that different characteristics of a population (i.e., body size or abundance) may be differentially affected by abiotic and biotic factors, even for ecologically similar, sympatric species. Understanding which traits are regulated by each component will advance our knowledge on how populations and communities are structured.

The digestive tracts of fishes contain a diverse set of gut associated microbiota known to contribute to many functions of the fishes' biology. Furthermore, it has been suggested that divergence in diets between two species is also associated with shifts in gut associated microbiota. Herein, we describe and compare the diet and gastrointestinal microbiota of two closely related combtooth blennies, Scartella cristata and Chasmodes saburrae (family Blenniidae) from Florida, USA. The diets of the two species were significantly different; C. saburrae consumed benthic or epiphytic crustaceans, while S. cristata consumed plants and detritus. Similarly, the gastrointestinal microbiota were significantly different between the two species. Gammaproteobacteria were the most abundant class identified in all samples, regardless of species, but S. cristata had higher relative abundances of Vibrionaceae, Methylococcaceae, and Fusobacteriaceae than did C. saburrae. These findings suggest that closely related species with vastly different diets results in distinct gastrointestinal bacterial communities. Lastly, digestive tract length and diet of these blennies were correlated with specific gastrointestinal microbiota, providing further evidence that these two factors may play a critical role in shaping gut microbial communities. Further research is necessary to tease apart the gut associated microbiota and transient microbiota and determine the role they play in digestion and trophic status of these fishes.

Toe-clipping is a standard technique for marking reptiles and amphibians individually, but concerns have been raised about the impact of the practice on animal welfare, survival, and behavior. We used a long-term mark-recapture dataset to investigate the impact of toe removal on free-ranging adult Cane Toads (Rhinella marina). Our analysis of 213 toads showed no impact of the number of toes removed on growth rates for mass or snout–urostyle length, nor any effect on body condition. Trials with sub-adult toads on a laboratory raceway revealed a short-term impact of toe-clipping on willingness to move (i.e., decreased immediately post-clipping), but no other significant impacts on locomotion. In summary, toe-clipping had minimal effects on Cane Toad locomotor ability, growth rate, or body condition.

A substantial body of work exists examining courtship in lungless salamanders (family Plethodontidae), but there are many species and population pairs that have not been tested for sexual isolation. Spotted (Desmognathus conanti sensu lato [SL]) and Southern Dusky Salamanders (D. aff. auriculatus) occur sympatrically within drainages in South Mississippi. I crossed individuals from three populations of D. aff. auriculatus (n = 6 individuals) and seven populations of D. conanti (SL) (n = 10) occurring in the Pascagoula and Pearl River basins. I alternated homospecific (n = 23) and heterospecific (n = 23) trials across nights in the spring and summer of 2014 and 2015, and I used GoPro™ HERO3 cameras and time-lapse photography to record the behaviors of a random subset of these pairs, as well as to determine the stage of courtship reached. Seventeen of the 23 homospecific trials resulted in spermatophore deposition and 14 in insemination. None of the 23 heterospecific trials (D. aff. auriculatus ♂ x D. conanti [SL]♀; or D. conanti [SL]♂ x D. aff. auriculatus ♀) reached this stage of courtship, but ten of the 14 photographed, heterospecific pairs exhibited pursuit and/or persuasive behaviors (i.e., pheromone transfer). These results suggest that D. aff. auriculatus and D. conanti (SL) are completely sexually isolated and that isolation is likely chemically mediated. I used a total of eight polymorphic microsatellite loci to genotype offspring from two clutches oviposited by a single female D. aff. auriculatus and one clutch oviposited by a female D. conanti (SL). Strict exclusion suggested that each clutch was sired by a single male, and that female D. aff. auriculatus and female D. conanti (SL) were capable of storing sperm for at least 4 mo 5 days and 3 mo 3 days, respectively. The data presented here further our understanding of the reproductive ecologies of Desmognathus in the historically understudied Gulf Coastal Plain.

The Southeast Asian cyprinid genus Crossocheilus was briefly described by Kuhl and van Hasselt in 1823 and, despite the short description, has remained a valid genus. However, the genus and its species are frequently misidentified in institutional collections, likely due to the absence of a detailed diagnosis and description, as well as the superficial morphological similarity with other cyprinid genera in the region. Crossocheilus and its constituent species are herein revised based on an examination of morphology and pigmentation. Eleven species are recognized, including a new species described from Indonesia. Crossocheilus pseudobagroidesis a junior synonym of C. langei. Crossocheilus tchangi is removed from synonymy with C. reticulatus and is a senior synonym of C. stigmaeus. Phylogenetic relationships among species of Crossocheilus based on sequences from the nuclear encoded recombination activating gene 1 are reconstructed. The resultant phylogeny is the most taxonomically comprehensive estimation of relationships among Crossocheilus to date and resolves C. atrilimes and C. oblongus, previously hypothesized to be sister species, not to be most closely related to one another.

Turtles are among the most vulnerable vertebrate group to declines, extirpations, and extinctions, especially those species with specific habitat requirements. The Bog Turtle (Glyptemys muhlenbergii) is listed as federally Threatened in the United States, but the southern population of the species does not receive full habitat protection under the Endangered Species Act. To understand Bog Turtle demographics within the southern population, we applied Cormack-Jolly-Seber and multistate models in program MARK and calculated annual adult, sex-specific, and juvenile survival for intensively sampled (19–180 sampling days) Bog Turtle populations in North Carolina. The most parsimonious model indicated that adult survival remained constant over time for all populations, but was relatively low when compared to other species of turtles. Adult survival estimates varied between 0.86 and 0.94 among the sites, all below the 0.96 adult survival estimate documented for northern Bog Turtle populations. To evaluate variation in juvenile survival, we focused on three populations: the two largest known populations and an intensely studied, but critically declining population. The two largest populations had a greater proportion of juveniles than other populations and higher juvenile survival (0.68 and 0.67) than the declining population (0.50). Thus, conservation efforts targeting juvenile survival and recruitment, such as nest protection and habitat enhancement, are important to ensure population stability. Furthermore, our estimates of adult and juvenile survival indicate that North Carolina populations are likely declining and without stronger protection measures, local and regional extirpations of the species may occur.

The widespread species, Chiloglanis occidentalis, is recorded in flowing waters from Senegal to Ghana. Recent studies of this species within the Upper Guinean Forests revealed genetic divergence among the populations sampled, suggesting the presence of several unconfirmed candidate species. A detailed study of these populations revealed morphological variation congruent with the molecular results. Nine new species are described herein: Chiloglanis camarabounyi, new species, Chiloglanis kolente, new species, Chiloglanis kabaensis, new species, Chiloglanis dialloi, new species, Chiloglanis loffabrevum, new species, Chiloglanis longibarbis, new species, Chiloglanis pezoldi, new species, Chiloglanis nzerekore, new species, and Chiloglanis tweddlei, new species. These new species, each endemic to specific river basins, are diagnosed through a combination of meristic and morphometric characters. Chiloglanis waterloti, from the Senegal and Niger river basins, is elevated from synonymy with Chiloglanis occidentalis, and Chiloglanis occidentalis is restricted to the Sassandra and Volta rivers in Côte d'Ivoire, and the Pra River in Ghana. A key for these new species and other species of Chiloglanis from the area is presented.

The lateral line scales are important features of bony fishes, but the three-dimensional configuration of the scales and the lateral line canal segments contained within them have been illustrated inaccurately in the literature. The lateral line scales of ten percomorph species (in Embiotocidae, Pomacentridae, and Pleuronectiformes [Bothidae, Pleuronectidae]) were studied histologically and in cleared and stained material. Canal diameter and the degree of overlap between adjacent lateral line scales appears to vary among species, but the lateral line scales are consistently oriented at a shallow angle, the cylindrical canal segments form a continuous canal that runs roughly parallel to the skin surface, one neuromast is typically found in the floor of each canal segment, and canal pores (when present) are perforations of the epithelium between adjacent lateral line scales. A new figure illustrates this anatomical configuration, which is in stark contrast to that portrayed in textbooks and in the primary literature, but is likely common among bony fishes. This work provides a new interpretation of a fundamental feature of bony fishes and highlights the ease with which inaccurate figures are disseminated and thus the need to verify the accuracy of anatomical illustrations.

Through a series of phylogenetic and taxonomic works, the unwieldy and non-monophyletic genus Barbus was reduced to just the typical Barbus of Europe and East Asia and most of the small, African, diploid barbs (‘Barbus'). The genus Enteromius Cope, 1867 was recently elevated to rename most of the small African ‘Barbus'; however, this designation has been controversial. Opponents of this change argue the designation was based on poorly supported phylogenies and state these changes would disrupt currently well-supported monophyletic groups; however, the genus is currently in use, and it is necessary to determine the species that should be recognized as Enteromius. Herein, we present a list of species placed in Enteromius and provide a description of the genus. We list the species of the other small African barbs (Barboides, Barbopsis, Caecobarbus, Clypeobarbus, Pseudobarbus, and ‘Pseudobarbus'). We also contribute 36 cytochrome b sequences of Enteromius to further build an understanding of the phylogenetic relationships among members of this group, and to aid in further taxonomic decisions.

Different types of animal camouflage ultimately have one function: avoiding detection. The most common form of camouflage, background matching, involves color patterns that match the surrounding environment while the individual remains motionless. However, in a dynamic environment, movement could also contribute to camouflage. For example, reverse crypsis or motion dazzle employs color patterns that can disrupt the pattern of motion to aid in concealing an individual, or by making it more difficult to track the individual's movements. Here I describe a new form of behavioral camouflage in colubrid snakes. The behavior consists of a series of small, laterally oscillating movements. Observed in three colubrids (Thamnophis sirtalis, Thamnophis sauritus, Opheodrys vernalis), I hypothesize that this behavior serves to blend the dorsal patterning of a snake with moving vegetation. Through 73 observations in T. sirtalis, the head-wobble was only observed being performed by small snakes in grassy/reedy areas while the wind was active. In the case of both species of Thamnophis, this may match the movement of grass in the wind with the dorsal stripe on the snake, and help a snake avoid potential predators.

A new species of Creagrutus of the subfamily Stevardiinae is described from the Río Cachiyacu, a tributary of the Río Huallaga in Peruvian Amazon. The species demonstrates a number of pronounced differences from the typical species of Creagrutus, most notably: the ventrally displaced jaws, the compressed, spatulate dentition and anterior portion of the neurocranium, along with modifications of the digestive system and the swimbladder. Its assignment to the genus is, nonetheless, supported by both morphological and molecular evidence. The new species is apparently mimetic of Prodontocharax melanotus, which also occurs at its type-locality.

Rivers are among some of the most complex and important ecosystems in the world. Unfortunately, many fishes endemic to rivers have suffered declines in abundance and distribution suggesting that alterations to lotic environments have negatively influenced native fish populations. Of the 35 fishes native to the Colorado River basin (CRB), seven are considered either endangered, threatened, or species of special concern. As such, the conservation of fishes native to the CRB is a primary interest for natural resource management agencies. One of the major factors limiting the conservation and management of fishes endemic to the CRB is the lack of basic information on their ecology and population characteristics. We sought to describe the population dynamics and demographics of three populations of Bluehead Suckers (Catostomus discobolus) and Flannelmouth Suckers (C. latipinnis) in Utah. Additionally, we evaluated the potential influence of altered flow regimes on the recruitment and growth of Bluehead Suckers and Flannelmouth Suckers. Mortality of Bluehead Suckers and Flannelmouth Suckers from the Green, Strawberry, and White rivers was comparable to other populations. Growth of Bluehead Suckers and Flannelmouth Suckers was higher in the Green, Strawberry, and White rivers when compared to other populations in the CRB. Similarly, recruitment indices suggested that Bluehead Suckers and Flannelmouth Suckers in the Green, Strawberry, and White rivers had more stable recruitment than other populations in the CRB. Models relating growth and recruitment to hydrological indices provided little explanatory power. Notwithstanding, our results indicate that Bluehead Suckers and Flannelmouth Suckers in the Green, Strawberry, and White rivers represent fairly stable populations and provide baseline information that will be valuable for the effective management and conservation of the species.

Insular Newfoundland has no native amphibians. While global amphibian populations are declining at alarming rates, populations of introduced anurans (frogs and toads) continue to expand in western Newfoundland, Canada. We expected the establishment and dispersal of the most recently introduced species, Mink Frog (Lithobates septentrionalis), to be influenced by the presence in the region of the previously introduced and ecologically similar Green Frog (L. clamitans). We used a combination of anuran calling surveys and pond-edge visual surveys to assess the ongoing dispersal, relative regional distribution, and local habitat use for these two species in western Newfoundland. The recently established Mink Frog has dispersed ∼3.8 km/year northeast from the original (2001) discovery location and ∼2.6 km/year southwest; co-occurrence analyses revealed that this population displayed habitat and spatial separation from long-established Green Frog populations, at both landscape and local scales. Although cause and effect is not established, this response appears to be defined, at least in part, by the influence of pH on species occurrence; Mink Frogs may be avoiding acidic environments which are tolerated by Green Frogs.

Labeotropheus is a genus of haplochromine cichlids endemic to Lake Malaŵi, Africa. Since its original description, surprisingly few additional species have been described, largely due to a misinterpretation of the historical taxonomic treatment of allopatric populations of Labeotropheus. Previously published evidence of genetic and morphological divergence among southern populations of Labeotropheus suggests that species diversity is underestimated. Morphometric, meristic, and color characteristics are employed to describe a new species of Labeotgropheus endemic to Mumbo Island and Thumbi West Island near the Nankumba Peninsula in southern Lake Malaŵi. The new species is distinguished from congeners by a wider body, longer pectoral fins, a shorter snout, and male nuptial coloration.