Population models depend on reliable estimates of vital rates, yet for many taxa, such estimates and how they vary in response to spatial or temporal environmental gradients are lacking. The goal of this review was to determine whether existing estimates of vital rates for temperate, direct-developing plethodontid salamanders (subfamily Plethodontinae) could be used to reasonably project values for populations or species where such estimates are lacking, or whether current estimates are biased in a manner that limits their utility. We synthesized current knowledge of stage-specific survival rates, age- and size-at-maturity at first clutch, and clutch frequency. We tested for expected correlations among published vital rates (e.g., age at maturity and survival) and between vital rates and factors such as body size or latitude. We used matrix projection models to judge whether published estimates were reasonably possible for stable salamander populations. The largest number of published vital rates were for clutch size, clutch frequency (proportion of females with clutches), size at maturity or first clutch, and age at maturity or first clutch, though the latter vital rate is primarily inferred from size distribution and growth rate data. Among these vital rates, we found expected correlations with body size and latitude suggesting these rates were reasonable and somewhat predictable among species or populations. In contrast, there were few estimates of egg hatch rate or juvenile or adult survival. Hatch and survival rate estimates were widely variable; estimates seldom included measures of uncertainty, but when uncertainty measurements were included, they were generally high. Based on projection models, few survival estimates were likely unbiased or realistic for stable populations given other salamander vital rates. Additionally, few studies quantified how vital rates vary with spatial or temporal environmental gradients. We outline the key knowledge gaps that limit basic demographic modeling of these remarkably common, influential, and otherwise well-studied salamanders, and make recommendations for future research efforts.

The California Grunion Leuresthes tenuis, a marine atherinopsid, makes spawning runs onto some of the busiest urban beaches of southern California. Eggs remain buried under moist sand, tidally emerged from water throughout incubation. Concern over the effects of human activities on beaches holding incubating fertilized eggs of L. tenuis prompted a need to assess spawning runs consistently through time. A new metric, the Walker Scale, focused on the peak of the runs, was developed to train citizen scientists, also known as community scientists. Reports of sightings were verified by scientists by locating buried clutches and collecting eggs at locations identified by volunteers. Reports between multiple observers from the same run were highly correlated, and also positively correlated with the density of clutches of eggs. Over the past two decades, the Walker Scale method has been used by thousands of volunteers as well as resource managers, environmental consultants, coastal projects, the US Army Corps of Engineers, and the California Department of Fish and Wildlife. This paper provides details about the method and its correct use by citizen scientists and professional biological monitors. The Walker Scale method is reliable, easy to understand, and the most effective method for assessing this elusive, charismatic fish.

Profundulus adani, new species, is described from the upper reaches of the Papaloapan River in the Mexican state of Oaxaca. The uniqueness of this new species is supported by morphological and molecular evidence. A combination of color patterns and counts separate P. adani, new species, from its congeners. Profundulus adani, new species, is distinguished from all congeners by the absence of a humeral spot in individuals larger than 45 mm SL. It can further be distinguished from P. balsanus, P. chimalapensis, P. kreiseri, P. oaxacae, P. parentiae, and P. punctatus based on the absence of series of dark dots on the sides of the body. Profundulus adani, new species, shows a faded dark band that extends from the tip of the operculum to the end of the caudal peduncle; this band is absent in P. balsanus and P. parentiae. The new species is described using specimens collected in the upper reaches of the Papaloapan River in the Mexican state of Oaxaca; geographically this represents a significant range expansion and extends the Atlantic slope northernmost limit of the Profundulidae.

Pond Turtle Shell Disease is an emerging infectious disease associated with the fungus Emydomyces testavorans (Emte). Here, we report the first documented case of Emte in free-ranging Californian turtles. We assayed Emte in nine Western Pond Turtles (Emys = Actinemys marmorata; WPT) and three non-native Red-eared Slider turtles (Trachemys scripta elegans; RES) from the same pond in Santa Cruz County, California. Despite several WPT exhibiting significant shell lesions, scute defects, and pliable scutes, all tested negative for Emte. However, all three RES were Emte-positive, although two of these showed no shell defects. Given all tested RES were Emte-positive, it is possible that some WPT results are false negatives, either due to assay performance or insufficient shell tissue sampling. However, our Emte results in WPT are likely true negatives, and thus our observations contrast the high prevalence of Emte and shell disease in WPT from Washington. The emergence of Emte in California poses a previously unaccounted conservation concern for imperiled WPT. Emte's presence in California is also an important opportunity to study the epidemiology and ecology of this pathogen in a contrasting environmental context to Washington state where shell disease has had pronounced conservation consequences. Given the recent discovery of Snake Fungal Disease in California and the substantial impact the amphibian chytrid fungus has had on California's amphibians, there is an urgent need to understand the spread, prevalence, and impacts of Emte and other emerging wildlife diseases in California and elsewhere.

Feeding performance represents a suite of kinematic events and behaviors that achieve the ecologically relevant task of nutrient acquisition. Quantitative accounts of feeding kinematics in large wild sharks are scarce but essential in understanding the ecomorphology of feeding in selachian fishes. This study presents quantitative and qualitative data on bite kinematics and feeding behavior in the Bull Shark, Carcharhinus leucas, using high-speed videography of wild specimens at Cape Eleuthera, The Bahamas. Our results support the hypothesis that bites of carcharhinid sharks, including C. leucas, follow a stereotyped sequence of kinematic events. However, there are interspecific variations in timing and duration of these events. The mean bite duration of 46 recorded bites by Bull Sharks approximately 1.4 m to 1.6 m in total length was 0.29±0.006 s. Bite duration did not vary significantly among the seven study animals, although it was negatively correlated with the angle, or pitch, at which sharks approached food items. The timing of upper jaw protrusion during the bite was correlated with the proximity of conspecifics. We discuss our results in the context of interspecific comparisons of bite performance among macrophagous, ram-feeding elasmobranchs and conclude that body size alone is not sufficient to explain interspecific variations in bite duration. We also discuss the benefits of field-based studies of feeding in sharks as an important complement to more traditional lab-based studies of performance.

This study investigated larval catfish abundance and diversity in various fluvial habitats in the Amazon lowlands of eastern Ecuador. It assessed the relationship between spawning behavior and the hydrological cycle, identified a potential spawning site, and elucidated community assemblages based on larval diversity among river tributaries with differing water chemistry profiles. Sampling sites included the mainstreams of the Napo and Aguarico Rivers and lower reaches of three tributaries. Drift samples were taken before, during, and after strong, rain-induced flooding occurred. Results suggest a strong peak of larval abundances in April, coinciding with the start of the flood period. In the Napo mainstream, samples were dominated by larvae of large migratory pimelodid catfishes, Pseudoplatystoma spp., which were caught between the upriver site in the foothills (254 m a.s.l.) and the downstream Peruvian frontier (175 m a.s.l.). Back-calculations based on water velocity and larval growth rate suggest that most of these larvae originated in the lowlands between those two locations, where the riverbed transitions from rocky to sandy/silty substrate. Thus, it appears that most spawning occurred over sandy substrates rather than the rocky substrates that were dominant above the upriver site. Comparisons of samples taken by day and night at the same sites revealed significantly higher larval abundances at night; thus, larvae must either preferentially drift at night, actively avoid the nets by day, or may do diel vertical migrations (e.g., related to predation pressure or pursuit of prey items). Dominant larval taxa in the whitewater mainstreams differed from those dominating samples from a blackwater mainstream system, and catfish larval assemblages in each of those habitats were distinct from those drifting in small, blackwater tributaries. These results provide key life-history information for catfish species in the Napo River, including for important commercial species, such as Pseudoplatystoma spp. Identification and protection of discrete spawning sites, such as those identified here, are critical to conservation efforts for these species.

Dussumieria torpedo, new species, is described from 18 specimens collected off the East African coast from Tanzania to South Africa. The new species closely resembles Dussumieria albulina in that both species have a deep body and a parasphenoid without teeth. However, D. torpedo, new species, is distinguished from D. albulina by having small pores posteriorly on the body scales (vs. numerous longitudinal striae posteriorly in D. albulina), a longer maxilla (33.4–34.9% of head length vs. 30.4–34.9% [less than 33.3% in specimens larger than 85 mm standard length]) and mandible (48.5–51.9% of head length vs. 44.8–50.6%), a greater number of pseudobranchial filaments (19–23 vs. 17–21), and indistinct melanophores scattered on the pectoral-fin rays (vs. distinct). A molecular analysis, which compared nucleotide sequences of the mitochondrial cytochrome oxidase I (COI) gene of the new species with those of all other valid species of Dussumieria, revealed that D. torpedo, new species, has >9% mean p-distance divergence from its congeners.

Freshwater fishes of the superfamily Cobitoidea are a species-rich group that are present in virtually every river in Europe and Asia. Three of the nine recognized families show massive karyotype reconstructions, including several independent cases of polyploidy, indicating cytogenetic evolution correlated with their diversification. We herein present the karyotype of a member of the monogeneric family Ellopostomatidae, a very rarely collected and morphologically highly enigmatic Southeast Asian representative of the Cobitoidea. The analyzed specimen of Ellopostoma mystax from southern Thailand had a diploid chromosome number of 2n = 48, with karyotype composed of three pairs of metacentric (m), 19 pairs of submeta- to subtelocentric (sm, st), and two pairs of acrocentric (a) chromosomes. Six pairs of sm to st chromosomes bore CMA₃-positive sites either in pericentromeric positions or formed CMA₃-positive p arms of the carrier chromosomes. Nucleolar organizing regions (NORs) as visualized by silver (Ag) impregnation were situated on the entire length of the shorter arms of the second largest sm to st pair of chromosomes; these corresponding sites also stained CMA₃-positive. When compared with other families of Cobitoidea, the karyotype of Ellopostoma reveals a rather plesiomorphic composition, suggesting that the strong derivation of Ellopostoma based on morphology only was not accompanied by a cytogenetic derivation.

A new species of ghost knifefish is described from the Rio Uatumã at Cachoeira do Miriti, Amazon basin, Brazil. It is distinguished from all species of Apteronotus by the absence of a clear stripe from the chin to the dorsal portions of the head and/or dorsum, a reduced number of anal-fin rays (118–122), and by having four branchiostegal rays. More specifically, the new species resembles Apteronotus quilombola by the low number of anal-fin rays; however, the number of branchiostegal rays and several additional counts and measurements differentiate the species. Furthermore, the new species co-occurs with A. lindalvae, and it can be distinguished by the number of premaxillary teeth. The occurrence area of the new species was highly impacted after the construction of Balbina dam. Thus, considering the threats to the species and the restricted area of distribution, its conservation status was assessed as critically endangered.

Distinct morphological differences between and within sexes may reflect reproductive behaviors that have evolved under natural and sexual selection. In some members of the Eurycea bislineata (Two-Lined Salamander) species complex, inter- and intrasexual variation in head morphology result from secondary sexual characters used in locating, courting, and guarding mates. In populations of Eurycea cf. wilderae (Blue-Ridge Two-Lined Salamander), males possess one of two suites of morphological traits corresponding to alternative reproductive tactics. “Searching” males appear to be adapted for locating and courting females in terrestrial habitats and are characterized by the seasonal development of mental glands, protruding premaxillary teeth, and elongate cirri. “Guarding” males appear to be adapted for aggressively guarding females in aquatic habitats, lack all three aforementioned traits, and are instead characterized by seasonally enlarged jaw musculature. Traditionally, males have been categorized by treating these traits as binary (i.e., present or absent), but this fails to capture any continuous variation. Here, we evaluated the utility of geometric morphometric methods to quantify and describe differences in head morphology among female, searching male, and guarding male E. cf. wilderae. In the left-lateral view, we found significant pairwise differences among all three morph–sex groups. In the ventral view, we found significant pairwise differences between searching males and guarding males and between searching males and females, but not between guarding males and females. Deformation grids clearly demonstrated the enlarged jaw musculature of guarding males and wider, flatter rostrum of searching males. Our results demonstrate utility of geometric morphometric methods for describing head shape differences among these alternative reproductive tactics and provide baseline data for future studies of spatial and temporal variation.

Complex environmental factors influence the distribution of species within lotic systems. This is especially apparent for amphibian species that have a multi-year larval stage. Pre-metamorphic Coastal Tailed Frogs (Ascaphus truei) are found in fast-flowing headwater streams for up to four years. Although there is considerable opportunity for the spatial redistribution of larval frogs, there is relatively little known of the habitat ecology of the various growth stages. We compared the abundance of larvae near the northern extent of the species range to a collection of environmental factors hypothesized to influence population density. We also assessed spatial segregation at various developmental stages where relatively short summers and cool climates result in a long residence for larvae. The top ranked model for larvae abundance included covariates representing the wetted width and wetted depth of the stream. Capture rates decreased in a nonlinear fashion as wetted width increased, and rates increased in streams wider than 6 m. Capture rates nonlinearly increased when stream depth exceeded 20 cm. Older larvae were associated with greater slopes than younger larvae. Our results suggest little evidence for a relationship between elevation and cohort distribution. We recommend considering micro-scale influences on the presence and movement patterns of Coastal Tailed Frog larvae within streams.

Senticolis triaspis is a widespread polytypic colubrid snake that ranges from the southwestern United States southward along the Pacific Coast and part of the Atlantic Coast of Mexico to Costa Rica. Three subspecies have been described based on differences in color pattern and scutellation: S. t. intermedia, S. t. mutabilis, and S. t. triaspis. The last taxonomic revision was completed in 1960. Here, we present an integrative taxonomic analysis of geographic variation using multiple sources of evidence: mitochondrial DNA (817 bp ND4 from 62 samples), traditional morphology (meristic and mensural characters), geometric morphometrics of head shape, and bioclimatic estimates of environmental niche similarity. Molecular data revealed two deeply divergent mitochondrial lineages corresponding to northern and southern clades and eight well-supported clades within these two main groups. Head shape and niche models also showed north–south differences, while traditional morphological analyses did not discriminate among mtDNA lineages. Thus, our study suggests there are at least two candidate species within Senticolis triaspis based on the mtDNA divergence, differences in head shape, and non-overlapping ecological niches. However, we refrain from making taxonomic recommendations pending the addition of nuclear DNA sequence data, finer sampling at contact zones, and additional morphological data; these data are warranted to provide a more robust, stable species delimitation.

The Philippine-endemic elapid genus Hemibungarus consists of three described species that are widely distributed across northern and central portions of the archipelago. Hemibungarus calligaster, H. mcclungi, and H. gemianulis were originally diagnosed, and remain recognized today, primarily based on differences in color pattern. Previous studies and faunal checklists suggest that these species occupy distinct geographic distributions within the Philippines. However, the relatively low numbers of specimens in collections and the misidentification of older specimens under outdated taxonomy have hampered a synthetic understanding of their actual distributional limits. Thus, an in-depth revisiting of the range of external morphological and color pattern variation within and among each species is still needed to clarify species boundaries and determine whether distributional limits change once properly documented. We provide a geographic assessment of morphological variation, using 98 specimens of Hemibungarus from institutional collections and public databases to reevaluate the range of phenotypic variation exhibited by each taxon and critically assess the geographic ranges of all three species of Hemibungarus. We use these data and multivariate statistics (principal coordinate and linear discriminant analyses) to demonstrate quantitatively how meristic data support the phenotypic distinctiveness of each species and to update the identifications of all accessible specimens. Georeferencing all specimens reidentified with morphological data indicates that H. calligaster is limited to central and northern regions of Luzon Island, whereas H. gemianulis is restricted to islands in central Philippines (Visayas). Hemibungarus mcclungi, previously considered restricted to the Bicol Peninsula in southern Luzon, appears to be more widely distributed—extending north into central and northern Luzon. We also identify a population of Hemibungarus that is intermediate in morphology between the parapatric H. calligaster and H. mcclungi, which raises the question of species boundaries and should be the focus of future study. Overall, our results provide a much-needed reconsideration of the identities of all available specimens in the world's biodiversity repositories, which use newly summarized data to elucidate the geographic distributions of the members of this enigmatic elapid genus, identify future directions for research on this group, and highlight the importance of returning to verified species occurrence data from the source (museum specimens) when considering biogeographical questions, species boundaries, and all related natural history studies.

Understanding how complex animal displays evolve is a major goal of evolutionary organismal biology. Here, we study this topic by comparing convergently evolved gestural displays in two unrelated species of frog (Bornean Rock Frog, Staurois parvus, and Kottigehara Dancing Frog, Micrixalus kottigeharensis). This behavior, known as a foot flag, is produced when a male ‘waves’ his hindlimb at another male during bouts of competition for access to mates. We assess patterns of variation in the color of frog feet and the kinematics of the display itself to help pinpoint similarities and differences of the visual signal elements. We find clear species differences in the color of foot webbing, which is broadcast to receivers during specific phases of the display. Analyses of foot-trajectory duration and geometry also reveal clear species differences in display speed and shape—S. parvus generates a faster and more circular visual signal, while M. kottigeharensis generates a much slower and more elliptical one. These data are consistent with the notion that color, speed, and shape likely encode species identity. However, we also found that foot flag speed shows significant among-individual variation, particularly the phase of the display in which foot webbings are visible. This result is consistent with the idea that frogs alter temporal signal components, which may showcase individual condition, quality, or motivation. Overall, our comparative study helps elucidate the variability of foot flagging behavior in a manner that informs how we understand the design principles that underlie its function as a signal in intraspecific communication.

Hydrology and dissolved oxygen (DO) availability drive wetland occupancy by zooplantivorous predators in the Prairie Pothole Region of the northeastern Great Plains, as follows. Permanent wetlands favor fishes, while the shallow waters of seasonal wetlands favor invertebrates and the larvae of the amphibian spring-breeding guild, including Tiger Salamanders (Ambystoma tigrinum). Semi-permanent wetlands fluctuate between these two extremities, holding water during wet years but drying during droughts, which means the aquatic vertebrate occupancy of these wetlands typically switches between fishes (wet periods) and amphibian larvae (droughts). Further, the shallow water of wetlands promotes hypoxic/anoxic conditions, creating “summerkills” and “winterkills,” primarily of fishes, which obligately breathe DO. Spring-breeding amphibian larvae avoid summerkills by air gulping—using their lungs to access atmospheric oxygen—and avoid winterkills by metamorphosing. Zooplankton, in turn, have several responses to these wetland conditions and their predators. In reaction to visually mediated, size-selective fish predation, small and semi-transparent zooplankton are selected for, and they undertake daily vertical migrations; the literature on this ecological interaction is vast. In response to intense invertebrate predation pressure, zooplankton become large. In response to wetland hypoxia, zooplankton upregulate hemoglobin (i.e., create blood), which makes them conspicuously red. Nocturnally active Tiger Salamander larvae use senses other than vision (likely lateral line mechano- and electroreceptors) to detect prey, permitting zooplankton to be large and red. The presence or absence of fishes or amphibians, combined with zooplankton morphology (small/large, semi-transparent/red), therefore create hypotheses regarding recent wetland conditions. This variability, while characterizing semi-permanent wetlands, is much more dramatic and dynamic than has previously been reported for palustrine basins. As such, by this and other criteria, I offer a synthesis built upon an understanding of respiratory physiology to explain the ecological communities observed in prairie wetlands.