Cylix nkosi, new species, of the formerly monotypic pygmy pipehorse genus Cylix, is described on the basis of the female holotype and the male paratype collected between 14–50 m over inshore warm-tropical coral reefs from KwaZulu-Natal, South Africa. The new taxon possesses derived characters consistent with the diagnosis of the type species Cylix tupareomanaia from Aotearoa New Zealand, including a prominent supraoccipital bone bearing a highly derived bony protuberance and the presence of distinct midventral head spines. The new species is distinguished from its congener primarily by the distinct shapes of the supraoccipital protuberance, midventral head spines, and the dorsomedial crest-like ridge on the first trunk ridge. Cylix nkosi, new species, can be further differentiated by genetic divergence in the mitochondrial COI gene from C. tupareomanaia and the morphologically similar members of the Indo-Pacific pygmy pipehorse genera Acentronura and Idiotropiscis (estimated uncorrected p-distances of 10.0% C. tupareomanaia, 16.6% A. breviperula, 20.6% A. tentaculata, 18.1% I. australe, and 18.8% I. lumnitzeri, respectively). Cylix nkosi, new species, is the first confirmed record of the genus in South Africa and the African continent. In addition, the occurrence of C. nkosi, new species, in the western Indian Ocean represents a substantial expansion of the geographical distribution of the genus beyond its original type locality in New Zealand.

Sea turtle hatchlings primarily use sight to detect differences in the angle of elevation in relation to the beach as well as light intensity present along the horizon to navigate from the nest to the water's edge. Artificial lights can cause visual disorientation (aimlessly wandering in circular paths around the nest) or misorientation (moving in distinct paths away from ocean). Several studies have been conducted on the effects high levels of light pollution associated with major cities can have on hatchling sea turtle orientation, whereas few studies have been done on the effects of comparatively lower levels of light pollution associated with rural areas, which are often considered ideal nesting habitats. This study examined lower light intensity found in areas surrounding large cities to identify if there is a threshold of light pollution above which hatchling orientation is negatively affected. During the 2016 nesting season, a Geovision GV-FER5303 non-illuminating infrared camera recorded hatchling trajectory at 21 Loggerhead Sea Turtle nests from areas varying in light intensity along the Grand Strand region of South Carolina. Fan spread, orientation deviation, and average crawl speeds were measured from each nest to determine if parameters associated with seafinding behavior were significantly affected by radiance conditions present at the time of emergence. Average crawl speeds were significantly influenced by radiance conditions, with faster average crawl speeds recorded for nests emerging under conditions when moonlight was present, and lower average crawl speeds recorded under low and high levels of light pollution. Studies that examine how sea-finding behavior could be altered, even in areas of relatively low radiance, can help inform management practices to enhance hatchling survival.

The production of glucocorticoids by the hypothalamic-pituitary-interrenal axis of amphibians and reptiles allows individuals to respond to acute stressors, but chronic elevation can have negative fitness consequences. Amphibians offer a unique opportunity to study the potential effects of elevated glucocorticoids, such as corticosterone (CORT), as lipid-soluble glucocorticoids readily pass through the skin and into the bloodstream. Interestingly, glucocorticoids are also secreted and excreted by amphibians to such an extent that relative rates of CORT release have been used to assess the relative ‘health’ of populations. Given that CORT has the potential to be both absorbed and secreted through the skin of amphibians and may have a negative impact on fitness, I attempted to assess the degree to which salamanders could identify ‘stressed’ conspecifics whose CORT levels were experimentally elevated through the use of a dermal patch. Plethodontid salamanders provide a convenient opportunity to evaluate the discrimination of ‘stress’ levels in amphibians because they utilize well-developed vomeronasal organs to facilitate a range of behavior, and their plasma CORT levels are readily manipulated via transdermal delivery. I tested the ability of Desmognathus ochrophaeus to detect and avoid substrates sullied by conspecifics with elevated CORT. The test was conducted via a simple choice experiment in which male and female test subjects were exposed to substrates sullied by an individual with baseline levels of CORT or the same individual with experimentally elevated CORT. Overall, I found that females did not differentially respond to substrates sullied by ‘high-stress’ females or males. Males did not avoid substrates sullied by high-stress males but did spend less time than expected on substrates from high-stress females. The differential response by males toward stimuli from high-stress females was replicated in a second study conducted approximately seven months after the first. These findings suggest that male D. ochrophaeus are capable of discerning among females, but not males, in ‘high-stress’ and ‘low-stress’ states. Female salamanders did not respond differently to substrates based on the stress level of stimulus donors.

As animals develop, demands on their physical form often change in response to ecological pressures. Structures associated with locomotion and habitat use can be particularly affected. Due to their smaller size, juvenile animals are often under selection to evade a larger and more diverse set of predators compared to adults of the same species. Adult Desert Horned Lizards, Phrynosoma platyrhinos, use a dorsoventral “shielding” as an anti-predator strategy to gape-limit potential predators. Because this strategy is likely size-dependent, we anticipated that juvenile lizards likely use different anti-predator strategies that would result in differences in habitat use, sprint performance, and morphology between age groups. We found differences in sprint speed and morphology, but not habitat use. Juvenile lizards had proportionally longer forelimbs and faster relative sprint speeds, potentially making juveniles more maneuverable than adults, though more work is needed to confirm this relationship. Our results suggest that selection for shielding behavior may constrain body shape throughout development, while shifts in limb lengths during development can enable juvenile lizards to evade their wider set of potential predators.

The Patagonian Redfish (Sebastes oculatus) is a viviparous species that inhabits the mid and outer shelf waters and rocky reefs off the Patagonian coast of Argentina where two morphotypes have been identified: the “dark” or “shallow” (mostly <30 m depth) and the “light” or “deep” (>80 m depth). Information on the reproductive biology of the “light” morphotype is scarce, so the main objectives are to describe the gonadal maturation phases and to determine the oocyte growth pattern of the species in deeper waters. In addition, we analyze the annual cycle of gonadal and liver condition indices in relation to sexual maturity and provide a preliminary estimate of potential fecundity. Samples were collected on commercial vessels by on-board observers between November 2016 and October 2017. The pattern of oocyte development showed that S. oculatus is a group-synchronous species, with gonad development beginning in the late austral winter and continuing into the spring, while larval emergence occurs in spring and early summer. Males mature before females, so copulation may occur in the fall, and females would retain sperm in the ovary until oocyte fertilization. The evidence suggests that viviparity of this species is lecithotrophic, and positive relationships have been found between relative fecundity with maternal size, which indicate that larger and older females have greater reproductive potential (producing more eggs than younger individuals).

Mountaintop endemic species are at particularly high risk of extinction due to a warming climate, yet very little is often known of the natural history of these species, especially in the tropics. One such poorly known tropical mountaintop endemic is the endangered Golden Treefrog (Phytotriades auratus, Hylidae). We conducted fieldwork on El Tucuche in Trinidad in an attempt to provide the first characterization of acoustic communication, tadpole diet, and parental care behaviors in this difficult to study, range-restricted, bromeliad specialist species. We succeeded in witnessing putative courtship behaviors which included not only acoustic vocalizations, but a surprisingly diverse acoustic repertoire. Four distinctly different call types were recorded, including two from a putative male (the “quack” and “eek” calls) and two from a putative female (the “trill” and “croak” calls). We provide quantitative descriptions of these acoustic signals and hypothesize functions for each. By photographing live tadpoles in the field and examining museum specimens, we found no evidence for eggs in the gut but abundant evidence of fine detritus. Despite some close relatives being bromeliad breeders with oophagous larvae, tadpoles of P. auratus appear to be detritivorous. Lastly, no clear interactions between adults and tadpoles were witnessed either in the field or on hundreds of automated video recordings, suggesting a possible lack of parental care behavior. While additional work is needed and many questions remain, these observations should begin to enable informed monitoring, conservation, and management activities for this at-risk species.

A new highly troglomorphic and diminutive swamp eel inhabiting muddy subsoil in remnants of a tropical rainforest in the Caribbean versant of Costa Rica is described. Comparative anatomical and mitogenomic data support the distinctiveness of the new species and its placement in the genus Ophisternon. The new species is unique among Neotropical congeners in having: 1) a greatly elevated number of precaudal vertebrae, 2) proportionally longer and larger premaxillary, dentary, palatine, and ectopterygoid teeth, 3) palatine and ectopterygoid teeth in a single row, and 4) a small, narrow, and crescent-shaped gill membrane opening. A novel phylogenetic hypothesis of synbranchid relationships proposed herein, derived from comparative mitogenomic data, adds to a body of evidence demonstrating that Ophisternon is not monophyletic (with respect to Synbranchus). This phylogeny, however, strongly supports the monophyly of Neotropical Ophisternon, with the new species resolved as sister to a clade consisting of Ophisternon infernale + Ophisternon aenigmaticum. A pattern of northwestern lineage dispersal and cladogenesis within the Neotropical clade of Ophisternon after its divergence from Synbranchus is inferred from our phylogenetic results and present-day species distributions. Our findings also reinforce the notion that the classification of synbranchid fishes is in dire need of a systematic and comprehensive revision, particularly with respect to the limits and composition of the genera with presence in the Neotropics.

Se describe una nueva anguila de pantano diminuta y altamente troglomorfa que habita el subsuelo fangoso en remanentes de una selva tropical en la vertiente Caribe de Costa Rica. Datos anatómicos y mitogenómicos comparados respaldan el carácter distintivo de la nueva especie y su ubicación en el género Ophisternon. La nueva especie es única entre sus congéneres neotropicales por presentar: 1) un número muy elevado de vértebras precaudales, 2) dientes premaxilares, dentarios, palatinos y ectopterigoideos proporcionalmente más largos y grandes, 3) dientes palatinos y ectopterigoideos en una sola fila, y 4) la abertura de la membrana branquial pequeña, estrecha, y en forma de media luna. Una nueva hipótesis de relaciones filogenéticas entre sinbránquidos aquí propuesta, derivada de datos mitogenómicos comparados, se suma a un conjunto de evidencia que demuestra que Ophisternon no es monofilético (con respecto a Synbranchus). Esta filogenia, sin embargo, apoya firmemente la monofilia de las especies neotropicales de Ophisternon, con la nueva especie resuelta como hermana de un clado que consiste en Ophisternon infernale + Ophisternon aenigmaticum. A partir de nuestros resultados filogenéticos y las distribuciones actuales de las especies, se infiere un patrón de dispersión y cladogénesis de linajes en dirección noroeste para el clado de las especies neotropicales de Ophisternon tras su divergencia de Synbranchus. Nuestros hallazgos además refuerzan la noción de que la clasificación de los peces sinbránquidos necesita urgentemente una revisión sistemática y exhaustiva, particularmente con respecto a los límites y la composición de los géneros con presencia en el Neotrópico.

Parental defense of offspring may be risky, so parents should balance costs and benefits, making context-dependent decisions based on the threat to offspring. Our previous field studies on Convict Cichlids, Amatitlania nigrofasciata, showed that the risk of brood mixing impacts aggression toward conspecific intruders. We also previously observed that parental pairs distribute differently in relation to conspecifics versus heterospecific pair locations with brood defense appearing to vary depending on intruder species (i.e., there appeared to be more aggression toward conspecifics than heterospecifics at closer distances). In the current study, we mapped pair distribution and found that more Convict Cichlid pairs had at least one neighboring pair within 3 m than did not. In addition, pairs with neighbors tended to be closer to heterospecific pairs than to conspecific pairs. To explore the relationship between the spatial distribution of pairs and parental defense behavior, we presented pairs of parental Convict Cichlids with stimuli consisting of a conspecific parental pair or a heterospecific parental pair (Hypsophrys nematopus). Each focal pair was exposed to each species separately and then simultaneously at both near (20 cm) and far (60 cm) distances. During separate presentations, focal parents were more aggressive at near distances versus far distances for both conspecifics and heterospecifics, though the aggression toward heterospecifics was always less than that toward conspecifics at each distance. In the simultaneous presentations, the focal parents were always more aggressive toward conspecific stimuli. These results support the idea that each species represent separate risks (such as conspecific brood mixing or predation) and benefits (such as shared offspring or territory defense) to reproductive fitness, which help shape the observed natural distribution of pairs.

We describe a new species in the Scinax granulatus group from the Atlantic Forest of northeastern Brazil and include the new species in an updated phylogenetic hypothesis for the group. The new species differs from all other species in the S. granulatus group by a combination of characters, such as a weakly bilobate vocal sac, moderately developed pre- and postaxial webbing of Toe IV, and advertisement call features. The newly described taxon is more similar with S. tropicalia, a species that is not closely related; both can be distinguished by the red-colored iris in the new species and differences in pulse rate of the call. The new species was recovered as the sister taxon of a clade including all other species of the S. granulatus group. However, the low support of some internal clades suggests that the knowledge about relationships in this group is still incomplete.

Leaf-frogs of the genus Phrynomedusa are rare phyllomedusine species known from a limited number of localities in the Brazilian Atlantic Forest, most of them known only from its small type series. Phrynomedusa fimbriata is known only from the holotype, a female collected in 1898. Despite subsequent efforts, no additional specimens have been collected or registered since this date, which led to the inclusion of P. fimbriata in the list of extinct taxa in the official Brazilian Red List. While examining the specimens deposited in the herpetological collection of the Museu de Zoologia da Universidade de São Paulo, Brazil, we discovered a second specimen of P. fimbriata, an adult male collected in the “Serra do Araraquara,” state of Paraná, Brazil, previously identified as Phrynomedusa appendiculata. Herein, we updated the diagnosis of P. fimbriata to include a description of an adult male and revised the doubtful voucher specimens identified as P. fimbriata and P. appendiculata in the herpetological collections outside of Brazil. In addition, we provide a new locality record of P. appendiculata in the state of São Paulo, Brazil.

Two new species of Rineloricaria are described from the trans-Andean region of Colombia. Rineloricaria atratoensis, new species, is distributed in the Atrato River and is distinguished by the absence of the mid-dorsal plate series and by having three rows of median abdominal plates, first (unbranched) ray of dorsal, pectoral, and pelvic fins extended as a short filament, and breeding males with hypertrophied odontodes on sides of head and dorsum of pectoral fin. Rineloricaria giua, new species, is found in the Magdalena and Ranchería Rivers and is distinguished by absence of mid-dorsal plate series and by having four or five rows of median abdominal plates, four plates along sides of dorsal-fin base, lateral margins of snout straight, and breeding males with hypertrophied odontodes on sides of head and dorsum of pectoral fin. Phylogenetic analyses of COI sequences of species of Rineloricaria from trans-Andean and Central American river basins revealed the different phylogenetic positions of the new species. Likewise, species delimitation analyses corroborated their status as independent lineages. An identification key for the trans-Andean and Central American species of Rineloricaria is provided.

Se describen dos especies nuevas de Rineloricaria de la región transandina de Colombia. Rineloricaria atratoensis, especie nueva, se distribuye en el río Atrato y se distingue por no tener la serie de placas dorsales medias, y por poseer tres series de placas abdominales medias, el primer radio (no ramificado) de las aletas dorsal, pectoral y pélvica extendido como un filamento corto, y machos reproductores con odontodes hipertrofiados en los lados de la cabeza y el dorso de la aleta pectoral. Rineloricaria giua, especie nueva, se encuentra en los ríos Magdalena y Ranchería y se distingue por la ausencia de la serie de placas dorsales medias, y por tener cuatro o cinco series de placas abdominales medias, cuatro placas a los lados de la base de la aleta dorsal, márgenes laterales del hocico rectos y machos reproductores con odontodes hipertrofiados en los lados de la cabeza y el dorso de la aleta pectoral. Los análisis filogenéticos de las secuencias COI de especies de Rineloricaria de las cuencas transandinas y centroamericanas, revelaron la diferente posición filogenética de las especies nuevas. Asimismo, los análisis de delimitación de especies corroboraron su condición de linajes independientes. Se proporciona una clave de identificación para las especies transandinas y centroamericanas de Rineloricaria.

Often organizations engaged in amphibian conservation are simultaneously trying to understand the mechanisms of species' decline and evaluate conservation actions employed to mitigate or reverse these declines. Capture–recapture monitoring methods are commonly used to identify and evaluate factors influencing population dynamics and associated vital rates, but these methods require individual identification for a subset of the population. Two commonly used anuran identification methods include passive integrated transponder (PIT) tags and pattern recognition. We combined these approaches via a double-marking method to quantify tag retention over five years and estimated potential effects of PIT-tagging on demographic rates for Western Toads (Anaxyrus boreas) in a reintroduced population in Colorado, USA. We used sharp, sterile scissors to cut a small dorsal incision (<3 mm) and inserted a 12 mm PIT tag subcutaneously. We found no negative effect of PIT-tagging on apparent survival, temporary emigration (skipped breeding), or recapture probability and no tag loss five years post-tagging. Vital rates from this reintroduced population were comparable or higher than those estimated from healthy populations in the same region. Our findings of 100% PIT-tag retention and no negative effects on toad demographic rates, together with high annual apparent survival and a growing population, suggest switching to PIT tags as an identification method is prudent for continued monitoring, though we encourage using the double-marking method for several more years until these findings are confirmed.

Understanding fundamental life history and ecological attributes of declining endemic fishes is essential for developing effective strategies for their conservation and recovery. In the Great Plains and desert rivers of North America, numerous imperiled leuciscids belong to a unique reproductive ecotype with drifting eggs and larvae (pelagophils). Herein, we synthesize three decades of research on the embryology and early life history of Rio Grande Silvery Minnow Hybognathus amarus, a federally endangered member of this ecotype, and explore how our findings can guide management and conservation of these sensitive taxa. We investigated three early developmental aspects of Hybognathus amarus through aquarium and laboratory studies: 1) egg morphology, development, and density, 2) larval development, growth, and behavior, and 3) morphologic and meristic analysis of larvae and early juveniles. Eggs nearly doubled in size at 10 min post-fertilization, were nonadhesive and nearly neutrally buoyant (specific gravity: 1.0011–1.0024), and hatched within 30 hrs in water about 23°C. Recently emerged protolarvae first transformed to mesolarvae after about one week, to metalarvae after about three weeks, and to juveniles after about six weeks at 20–24°C. Based on six candidate models, larval fish development (i.e., from protolarvae to early juveniles) was best explained by a cubic polynomial growth curve. While most protolarvae developed a gas bladder and began to feed within a week, the complete complement of fin rays (i.e., required for proficient swimming) had not fully formed until about one month post-hatching. Early developmental characteristics (e.g., egg specific gravity and larval fin ray formation), combined with river fragmentation, flow regulation, and habitat loss, can profoundly affect the upstream retention and recruitment of Hybognathus amarus and other native pelagophils. Long-term recovery of these highly imperiled species will depend on restoring sufficient seasonal flows, river and floodplain connectivity, and habitat complexity to promote their successful spawning, growth, and survival.

The diverse deep-sea order Stomiiformes includes 457 species of mesopelagic and bathypelagic fishes with a remarkable diversity of structures associated with feeding, locomotion, and bioluminescence. This study investigates their patterns of body-shape evolution using geometric morphometry in an ecological and phylogenetic context. A total of 473 specimens from 56 different species in 48 genera representing all five families were photographed and 14 homologous landmarks and 50 semilandmarks were marked on the digital images. A principal component analysis (PCA) visualized body-shape variation, and morphological disparity analysis evaluated differences in variance among species in relation to their dietary classes, habitat partitioned by depth, and the presence or absence of diel vertical migration. The study also tested phylogenetic and ecological signals. The PCA revealed that variation in fin size and position, particularly for the dorsal and anal fins, accounted for the most important axis of variation among species. Changes in relative body size and body depth also contributed to morphological diversity. There is a trend toward body elongation in relation to depth distribution, with the meso-bathypelagic species having more elongated bodies than those restricted to the mesopelagic zone. Piscivorous and generalist species exhibit higher morphological disparity when compared to zooplanktivorous species, and meso- to bathypelagic species exhibit higher morphological disparity when compared to strictly mesopelagic species. A high phylogenetic signal indicates that morphological diversification within the Stomiiformes fits the expectations of Brownian evolution, in which the degree of shared ancestry rather than similarity of ecological niche predicts anatomical similarity. However, the current dataset may lack the statistical power to uncover any causal relationship between shifts in depth, diet, or migration and the shape diversification of stomiiforms.

Warming temperatures are known to influence ectotherm life history and physiology. As climate change increases global temperatures, the consequences of direct and indirect effects of warming are becoming of high interest in biology. Warming temperatures could alter daily activity, change rates of food consumption, and influence allocation of energy, altering life history. Lizards are a taxon of concern regarding climate change, with documented thermal sensitivity in physiological performance and life history. The current study used a series of meta-analyses to examine how body temperature, food consumption, duration of daily activity, and growth rate influence lizards. The results indicated that warming temperatures increased food consumption but decreased growth rate. Meanwhile, increasing food consumption increases lizard growth rate. However, mechanistic studies are needed to determine the factors dictating identified trends, as the current approach is correlational. Overall, few data were available for the parameters of interest, with zero studies quantifying the influence of daily activity on food consumption. Restrictions in daily activity are a primary consideration with climate change models for lizards; however, empirical data quantifying the effects are lacking. The current study identified fruitful areas for future research, specifically on the effects of daily activity on energetics to understand indirect and direct effects of climate change.

The monographic series Fishes of the Western North Atlantic (FWNA) is widely used as a reference for fishes of the region. The original goal of FWNA was to develop comprehensive species accounts to address the identification, nomenclature, biology, and distribution of all the fishes in the region; however, only ten Parts were completed, from the lancelets, cyclostomes, and sharks in 1948 to the needlefishes, halfbeaks, sauries, and flyingfishes in 2019. Production of FWNA engaged broad participation from the ichthyological community with 48 authors from 28 institutions, including museums, universities, federal and state agencies, and marine laboratories. With publication of Part Ten, the series concluded, and all Parts were reissued. Here we present a history and evolution of the series over the 85 years since the series was proposed in 1937 and assess its impact on ichthyology, the ichthyologists who participated in FWNA, and the institutions that supported them.