Etheostoma cyanorum, endemic to the Blue River drainage of southern Oklahoma, is redescribed and recognized as a distinct species within the Etheostoma whipplei–Etheostoma radiosum complex, separating it from E. radiosum. Originally described as Poecilichthys radiosus cyanorum, it was one of three putative subspecies of E. radiosum (with E. r. radiosum and E. r. paludosum) considered valid until now, defined in part by drainage-specific allopatry. Two separate mtDNA gene trees show that E. cyanorum forms a distinct and strongly supported lineage. Ten meristic and 16 morphometric traits are reexamined and new information included, confirming traits separating E. cyanorum from E. radiosum, and clarifying ambiguities about “bluntness of the snout” as diagnostic for P. r. cyanorum. Etheostoma cyanorum differs from E. radiosum by lower counts of unpored lateral line scales, higher counts of pored lateral line scales, and greater interorbital width. Large adult E. cyanorum have a deep body and blunt snout per earlier studies, but those traits are not diagnostic due to allometry. Head depth and head width can separate E. cyanorum from most populations of E. radiosum, but they overlap with some populations of E. radiosum in southwest Arkansas. All evidence supports recognition of E. cyanorum as a valid species. A broad geographic, molecular assessment to supplement existing morphological information is needed to assess validity of the two remaining subspecies of E. radiosum.

The dynamic, multiscale nature of stream systems makes it challenging to establish basic ecological principles to guide stream fish conservation and management. For example, finer-scale instream habitat is often constrained by coarser-scale characteristics driving observed species distributions. Additionally, instream environmental variability can result in patchy species distributions within general upstream–downstream occurrence patterns (i.e., variation around a common theme). Groundwater contribution, an often-overlooked habitat characteristic in warmwater systems, has numerous influences on the instream environment and can play a role in fish habitat-use patterns and assemblage structure. We identified multiscale instream habitat characteristics associated with the occurrence probability of 20 Ozark Highland stream fishes. Fishes were surveyed using tow-barge electrofishing in 76 channel unit complexes (i.e., riffle-to-riffle habitat sequences) nested in 20 reaches of northwest Oklahoma and southwest Missouri. We used a multiscale, multispecies generalized linear mixed model to identify relationships between fish occurrence and both channel unit complex- and reach-scale variables. Stream fishes were more likely to occur in larger or deeper channel unit complexes. Fish occurrence was also associated with different levels of reach-scale groundwater contribution, bankfull width-to-depth ratio, and percent instream cover. Ten fishes, typically associated with warmer water temperatures, had lower occurrence probabilities in reaches with higher groundwater contribution, whereas Banded Sculpin Cottus carolinae and Creek Chub Semotilus atromaculatus occurrence probabilities were higher. There was no relationship between occurrence probabilities and instream cover for 11 fishes. The occurrence probabilities in relation to varying amounts of instream cover for the other nine stream fishes was dependent on bankfull width-to-depth ratio, where the direction and magnitude of the relationships varied among stream fishes. The variation in occurrence relationships can be attributed to thermal preferences, environmental interactions, and the use of multiple habitat types. Our findings demonstrate the multiscale nature of fish occurrence relationships and how conservation and management may benefit from considering this complexity when developing holistic instream habitat enhancement strategies.

A new species of Moenkhausia is described from Rio Curicuriari and Rio Tiquié, both right-bank tributaries of the upper Rio Negro basin, Amazonas State, Brazil. The new taxon differs from all congeners, except M. agnesae and M. beninei, by the combination of a sinuous humeral blotch, similar to a compressed letter Z, and distinct dark longitudinal stripes along the body sides. The new species can be distinguished from M. agnesae and M. beninei by the presence of a single humeral blotch and of longitudinal stripes running through the center of the scales, more conspicuous dorsally.

The blind snake Anomalepis colombia was described based on a single specimen, and since the collection of this specimen by Kjell von Sneidern in January 1946, there are no records of other specimens in scientific collections. This species is known only from the type locality in La Selva, Pueblo Rico, Caldas, Colombia. In this study A. colombia is redescribed based on external morphology and a detailed osteological description of the skull, prepared by high-resolution x-ray computed tomography.

Understanding community interactions, such as predator–prey dynamics, is vital for determining species viability. Outside of larger macroinvertebrate predators, such as crayfish and dragonfly larvae, there is a paucity of information regarding the effectiveness of other macroinvertebrate predators in consuming larval amphibians, especially caudate larvae, during aquatic life-stages within pond communities. In this study, we tested the ability of a suite of macroinvertebrate predators to consume Spotted Salamander larvae (Ambystoma maculatum) at two points during larval development. We tested the ability of macroinvertebrate predators belonging to the genera Belostoma, Lestes, Notonecta, and Ranatra, the families Aeshnidae, Dytiscidae, Gomphidae, Gyrinidae, Hirudinae, Libellulidae, and Notonectidae, or order Trichoptera, as well as larvae of Rana clamitans, to consume A. maculatum immediately after hatching and several weeks into their larval period across four separate experiments. We tested for significant differences in percent survival of A. maculatum among predator treatments using ANOVA. Across all trials, we found a significant effect of predator treatment. Both hatchling and larval A. maculatum were susceptible to predation by Aeshnidae and Notonectidae. In all other treatments, we observed low or zero mortality of hatchlings of A. maculatum and 100% survival of larvae of A. maculatum. As Aeshnidae and Notonectidae are both gape unconstrained predators, the increase in larval size did not appear to increase survival of A. maculatum due to increased escape performance. Overall, rates of predation are low for A. maculatum for most macroinvertebrates during the tested life stages, suggesting that predation by only a handful of invertebrate taxa and vertebrates contribute to high mortality rates within this system.

We describe herein a new polychromatic species of the snake genus Atractus from the cloud forests of the northeastern Andes of Colombia. The new species is distinguished from all congeners by having an exclusive combination of phenotypic characters, such as: dorsal scale rows 17, loreal long, seven to ten maxillary teeth, ventrals 156–174 in females and 153–169 in males, subcaudals 20–30 in females and 23–30 in males, dorsum with variable coloration, changing from dark green to orange or red with a black nuchal band (three to four scales long) connected to a black vertebral line and two black dorsolateral continuous stripes from the occipital region to tip of the tail, venter with irregular black blotches, relatively small body size, small tail length in females and moderately long in males, hemipenis moderately bilobed, semicapitate and semicalyculate. We compared the new species with all congeners occurring along the Cordillera Oriental in Colombia, Sierra de Perijá in the Colombia/Venezuela frontier and Cordillera de Mérida in Venezuela. We discussed aspects related to polychromatism and its implication toward a robust taxonomy for the genus Atractus.

Describimos una nueva especie de serpiente policromática del género Atractus para los bosques nublados del noreste de los Andes de Colombia. La nueva especie se distingue de todos los congéneres por tener una combinación exclusiva de caracteres fenotípicos, como: escamas dorsales en 17 hileras, loreales largas, siete a diez dientes maxilares, ventrales 156–174 en hembras y 153–169 en machos, subcaudales 20–30 en hembras y 23–30 en machos, dorso con coloración variable, cambiando de verde oscuro a naranja o rojo con una banda nucal negra (largo de tres o cuatro escamas) conectada a una línea vertebral negra y dos franjas continuas dorsolaterales negras desde la región occipital hasta la punta de la cola, superficie ventral del cuerpo con manchas irregulares negras, tamaño corporal relativamente pequeño, longitud de la cola pequeña en las hembras y moderadamente larga en los machos, hemipene moderadamente bilobado, semicapitado y semicaliculado. Comparamos las nuevas especies con todos los congéneres que ocurren a lo largo de la Cordillera Oriental en Colombia, Sierra de Perijá en la frontera de Colombia/Venezuela y la Cordillera de Mérida en Venezuela. Discutimos aspectos relacionados con el policromatismo y su implicación hacia una taxonomía sólida para el género Atractus.

With some 400 known species, the lizard genus Anolis is one of the most species-rich groups of terrestrial vertebrates in the world. Widely distributed, they occur throughout Central and South America, the West Indies, and the southeastern United States. Although anoles have emerged as paradigmatic species in ecology and evolution, relatively little research has addressed the effects of climate change on their distributions. Over the past 40 years, Puerto Rico has experienced steady increases in ambient temperature with mean maximum temperatures rising by as much as 2°C. Using distribution data from the Puerto Rico Gap Analysis, WorldClim bioclimatic variables, and MaxEnt niche modeling software, we projected potential changes in the distribution of ten species of Puerto Rican anoles for 2050 and 2070. All of our models used either the HadGEM2-AO or the MRI-CGCM3 Global Climate Model, each paired with the IPCC's Representative Concentration Pathways (RCPs). RCP4.5 was chosen as it represents a scenario in which greenhouse gas concentrations rise in the Earth's atmosphere until the year 2040 and then begin to decline. RCP8.5 was chosen as it represents a likely scenario of continued high greenhouse gas emissions through 2100 and acts as the IPCC's worst-case scenario of warming. Under HadGEM2-AO RCP8.5 for 2050, Anolis krugi, A. evermanni, and A. gundlachi are the most negatively impacted species, while for MRI-CGCM3 RCP8.5 for 2050, the most negatively impacted species are A. cuvieri, A. gundlachi, and A. evermanni. The models also predict mean reductions in most suitable habitat across all ten species of Anolis, ranging from –29.4% by 2050 to –39.6% by 2070 under HadGEM2-AO RCP8.5, and from –10.6% by 2050 to –28.5% by 2070 under MRI-CGCM3 RCP8.5. Our study provides insights into the potential impact of continued climate change on Puerto Rican anoles, and most likely other West Indian species of Anolis, and has important implications for future conservation efforts.

The prevalence of studies that discern the drivers of animal migrations is increasing exponentially, in line with raised concerns over climate-driven shifts in phenological patterns. Amphibians that breed in ephemeral wetlands are particularly vulnerable owing to the stochastic nature of their breeding habitat and high survival and reproductive costs associated with untimely migrations. Knowledge of the effects of climatic cues on the timing of amphibian migration and breeding phenologies is required to understand the potential consequences of climate change and to inform conservation plans for at-risk species. Here we use six years of count data from Eglin Air Force Base, Florida, U.S., collected between 2010 and 2016, to model the phenology of migrations of Ambystoma bishopi. Models were fit with a negative binomial error distribution, with daily values of temperature and precipitation as covariates. Models were compared in an AIC framework. We found that salamander movement was strongly tied to environmental cues. A proclivity to move over a medial range of temperatures and precipitation resulted in a ‘Goldilocks’ set of conditions that facilitate migration. We also discovered a role for endogenous drivers of movement, with day of year predicting above-ground activity regardless of environmental conditions. These results contribute to our basic knowledge of the behavior of A. bishopi and provide managers with useful metrics to maximize the efficacy of conservation actions. More broadly, the methods employed within have utility to amphibian researchers to help predict the effects of climate change and tailor management strategies accordingly.

In situ images and/or collection of seven specimens by underwater-vehicle dives at 269–609 m depth off Curaçao, Dominica, and Puerto Rico (S, E, and NE Caribbean) revealed new records and a previously unknown, distinctive color pattern for the cuskeel Neobythites unicolor (Ophidiidae). Species identification was based on detailed comparisons with earlier studied type and non-type material using morphometric, meristic, and otolith-form characters. A revised color description is provided based on images of live specimens in situ in their habitat, shortly after capture, and after preservation. Live and fresh specimens of Neobythites unicolor show a large number of distinctive, dark, rounded or irregularly shaped spots distributed dorsally on head, dorsal portion of body, and on the dorsal fin. This color pattern fades when fish are frozen, and it is completely lost during preservation over several years. The available images of fresh color patterns indicate an increase in spot size with fish size. In addition, some of the quantitatively examined morphometric and otolith characters of museum specimens show positive allometry. No geographic variation in color patterns could be detected. Although the Curaçao population is separated from all other known populations of N. unicolor by at least 650 km, the only population difference found was a slightly lower pectoral-fin ray count for the four specimens collected off Curaçao. An updated distribution map is provided correcting for an erroneous record in the inner Gulf of Mexico from which N. unicolor appears to be completely absent. While the spotted color pattern described here is unique among the 54 species of Neobythites, a similar pattern occurs in two other genera of the subfamily Neobythitinae, Sirembo and Spottobrotula. Further requirements to more fully understand the color diversity and related biology, ecology, and evolution in the species-rich genus Neobythites are emphasized.

The lack of tools for sex identification and assessment of gonadal development are hindering our ability to study the reproductive dysfunction of Arapaima gigas in captivity. This study initially aimed to validate a non-surgical endoscopy procedure to identify sex in juveniles and assess stage of ovary development in female broodstock under field operational conditions. Cannulation, assisted through the description of the genital anatomy, made ovarian biopsy possible to describe oocyte development from primary growth to pre-ovulation, providing a first classification scheme for oogenesis in the species including description of the micropyle morphology using scanning electron microscopy. Cannulation was also successfully performed without endoscopic guidance, which allowed monitoring of ovarian development along the reproductive season together with profiling of plasma sex steroids (17β-estradiol [E₂] and 11-ketotestosterone [11-KT] in females and males, respectively). The monitoring of our study population showed females paired with males in earthen ponds sexually matured and reached oocyte maturation during the spawning season. However, since no spawning was recorded, eggs had either been resorbed or released and not fertilized by the male. Plasma E₂ levels remained high in females, as expected in an asynchronous species during the spawning season with multiple batches of oocytes being recruited. Plasma 11-KT showed a tendency to decrease, suggesting a male reproductive dysfunction or the end of the reproductive season with a lack of synchronization between sexes. In conclusion, endoscopy and cannulation are tools that can be promptly applied to aid sex identification, assessment of reproductive function, and overall broodstock management in wild and captive stocks. These tools will greatly help future studies looking at the effects of environmental, social, and hormonal cues on reproductive development with the aim of developing a spawning induction protocol for the species.

Genomic data can provide novel insights into the natural history of oceanic species. These data can inform the management of vulnerable and slow-maturing species by estimating population structure, rates of migration, and the distribution of genetic diversity. In this study we focus on two protected elasmobranch species, the Winter Skate, Leucoraja ocellata, and the Little Skate, L. erinacea. We use genome-wide SNPs to estimate population structure, and quantify migration and genetic diversity among both species from four sampling localities across the Atlantic coast of North America. We find that species of Leucoraja are generally isolated by distance, although we infer some fine-scale population structure. Specifically, estimates of effective migration infer fine-scale population structure in L. ocellata between the northern sites of Georges Bank and the Mid-Atlantic sampling sites, whereas L. erinacea shows no evidence of population genetic structure in any analyses. We also found that genetic diversity is concentrated in the central sites of Georges Bank and the Mid-Atlantic Bight for L. ocellata, but is reduced at these two sites in L. erinacea, suggesting opposite distributions of genetic diversity between species. Thus, genomic data suggest that while species of Leucoraja lack discrete population structure, they likely employ only mid-range dispersal. These findings correspond to ecological studies that have found eco-physiological differences between embryonic and juvenile Leucoraja from different localities. Taken together, small-bodied skate research emphasizes the importance of local adaptive plasticity for marine species, even without population genetic structure. Conservation strategies should focus on managing the portions of the Atlantic coast considered most vital to reproduction of Leucoraja, but should not recognize multiple populations across their range.

Gymnotiform electric fishes exhibit many forms of sexual dimorphism, including sexual size dimorphism (SSD), aspects of head, jaw, and electric organ morphology, and electric signal waveform. However, sexual dimorphism is poorly documented in banded electric fishes (Gymnotus), where most species are monomorphic in external appearance and electric signal waveforms. Gathering comparative data on species of Gymnotus has historically been hampered by their predatory and territorial lifestyles, in that they are usually dispersed in their preferred habitats and often collected individually. Here data are presented from a population of G. javari from the Peruvian Amazon, examined for SSD (n = 55) and electric organ discharge (EOD) amplitude (n = 162). These results are compared with a syntopic population of G. carapo (n = 61), and also with G. omarorum (n = 24) from a population in Uruguay. Unlike most congeners, G. javari exhibits pronounced sexual dimorphism in total length and body weight, and EOD pulse amplitude is correlated with total length. A review of several ecological hypotheses on body-size distributions of each sex as a balance of multiple competing selection pressures finds none of these hypotheses adequately explain SSD in G. javari. Examining SSD in biogeographic and phylogenetic contexts leads to the conclusion that selection across different environments (e.g., local habitats, geographic regions) and through evolutionary time may have contributed to the evolution of SSD in some but not all lineages of Gymnotus.

A new Southwestern Atlantic species of Parmaturus, P. angelae, new species, is described from two specimens captured off Brazil. It is distinguished from congeners by the following characters: origin of the first dorsal fin anterior to pelvic-fin origin, presence of well-developed upper and lower caudal crests of denticles, dorsal fins subequal, lateral denticles teardrop-shaped and lacking lateral cusplets, denticles evenly spaced, proportional dimensions, and vertebral counts. Parmaturus angelae, new species, is the second species of the genus reported from the Atlantic Ocean and only the third species outside of the Indo-West Pacific region. Parmaturus remains rather poorly defined as only two species have been studied anatomically in any detail.

Pomacentrus vatosoa, new species, is described on the basis of four specimens collected from Nosy Faho, Madagascar. The new species is distinctive in having a pearlescent-white body with a large black spot midlaterally behind the pectoral fin, a black saddle of similar size on the dorsal edge of the caudal peduncle, and a black recurved band from the orbit to origin of dorsal fin. Aside from details in live coloration, the new species is readily diagnosed from congeners in having the following combination of characters: dorsal-fin rays XIV, 13–14; anal-fin rays II, 14; pectoral-fin rays 18–19; tubed lateral scales 19–20; gill rakers 5–6+17–18 = 22–24; infraorbitals naked; teeth on lower jaw partly biserial; no distinct notch between infraorbitals 1 and 2; and a crescent opening of the supraorbital canal above the eye. The new species appears to be most closely related to Pomacentrus atriaxillaris on the basis of meristic data, though comparative molecular sequences for P. atriaxillaris are lacking. Assignment of the new species to the genus Pomacentrus is accompanied with a brief discussion of the systematic contention within the Pomacentridae.

Habitat preference is determined by complex interactions between biotic and abiotic habitat features and species-specific requirements. In many terrestrial organisms, studies of habitat preference emphasize the role of vegetation. Yet, in land-dwelling ectotherms, an often-overlooked characteristic that may have a strong effect on habitat preference is soil type. We followed 18 Spur-thighed Tortoises (Testudo graeca) mounted with radio transmitters to quantify their seasonal activity patterns, home-range sizes, and preferred habitats, including soil type. We used Maximum Entropy to quantify the spatial distribution of Testudo graeca in the study area based on species occurrence records and nine environmental variables derived from LiDAR. We describe for the first time a strong preference for soil type in Testudo graeca, as well as preference for flat terrain (avoidance of steep slopes). Individuals avoided areas with dense woody vegetation and chose habitats containing heterogeneous vegetation, including isolated trees, shrubs, and open patches. We further found that individuals in the study area do not hibernate but decrease activity in summer-autumn. Finally, home-range size was comparable between the sexes. The overlapping home ranges within and between the sexes throughout the year, including the mating season, suggest that this species is not territorial.

Fishes of the family Muraenidae (moray eels) comprise two subfamilies of highly specialized benthic forms. As first documented and described in two earlier papers, morays have a highly specialized raptorial feeding apparatus in which they move their upper pharyngeal jaws forward into the oral cavity to grasp prey and transport it back into the esophagus. Here I revisit the descriptive aspects of the second paper and compare them to my own investigations of the topographic anatomy of this apparatus. Regrettably, my observations of the relevant anatomical details and terminology differ markedly from those presented in that paper. Accordingly, I describe and illustrate my observations, compare them to previous descriptions, and discuss possible functional implications. In contrast to the earlier paper, I offer detailed argumentation and justification for my terminology and identification of relevant gill-arch muscles in muraenids. Based on my re-interpretation of the topographic anatomy of the pharyngeal musculature, three conspicuously different anatomical mechanisms of pharyngeal jaw protrusion and retraction are identified.