Shifts in phenology have been one of the most frequently documented effects of climate change across a wide variety of taxonomic groups. These shifts can alter both species and ecosystem level processes and, for species of conservation concern, may impact the effectiveness of ongoing management programs. Here, we used ten breeding seasons (2010–2020) of drift fence data to quantify the breeding phenology of the imperiled Reticulated Flatwoods Salamander (Ambystoma bishopi) at two breeding wetlands in Florida. We then used downscaled climate projections from three Global Circulation Models (GCMs; Hadley Centre Global Environment Model 2 Earth Systems, Hadley Centre Global Environment Model 2 Carbon Cycle, and the Community Climate System model version 4) each with two emission scenarios to forecast how flatwoods salamander breeding phenology may change from 2030–2099. We combined these forecasts with an existing hydrologic model that was built using the same climate data to examine how wetland hydrology and phenology may interact to impact salamander recruitment in future years. We found that large movements (≥ 5 individuals) of adult salamanders moving into breeding wetlands were tightly linked to precipitation events with minimum temperatures above freezing, while juvenile emigration was less strongly tied to precipitation and occurred on more days than adult immigration. Under all six GCM-emission scenario combinations, only one scenario suggested that there would be fewer immigration opportunities by the year 2099, and two scenarios (both high emission) indicated that the timing of immigration may shift to later in the fall breeding period. All projections predicted that only a few years will have an ideal intersection of phenology and hydrology for flatwoods salamander reproduction but that many years would have marginal conditions where recruitment may still be possible. Because the frequency of successful breeding years affects population viability in flatwoods salamanders, ongoing management programs must ensure that populations are reproducing frequently enough to remain viable. Overall, our results indicate that altered wetland hydrology (e.g., shorter hydroperiods during the breeding season) and other effects of climate change (e.g., sea level rise) are more likely to contribute to flatwoods salamander declines over the next several decades than phenological shifts.

There are presently four recognized species of clinid (kelpfish family: Clinidae) on the west coast of North America: Gibbonsia elegans, G. metzi, G. montereyensis, and Heterostichus rostratus. In addition, Clark L. Hubbs proposed an endemic subspecies in the genus Gibbonsia on Guadalupe Island. Later investigations using allozymes indicated low levels of genetic diversity between populations and treated subspecies names as synonyms, leading to the present-day status of three species in the genus. Here, we use high-throughput sequencing and a combination of nuclear and mitochondrial markers to revisit the systematics and population structure of the genus Gibbonsia. We find that Guadalupe Island specimens that are morphologically identified as G. elegans form a distinct genetic lineage for both nuclear and mitochondrial markers, supporting Hubbs's hypothesis of a Guadalupe Island endemic, Gibbonsia erroli. Further, we find that while dispersal potential is high for all species in the genus, genome-wide markers and outlier analyses show population structure at short geographic distances, suggesting fine scale environmental variation leading to local adaptation.

Adaptation and modularity are two major features of morphological evolution that are increasingly investigated by modern macroevolutionary biologists. However, many such studies assume that adaptive processes or modularity are constant across species. Evolution of morphology and its modularity both relate to the ecological role of morphological traits. Here, we investigate whether morphological adaptation and modularity vary across families of the Neotropical superfamily Doradoidea, comprising the Aspredinidae (banjo catfishes), Auchenipteridae (driftwood catfishes), and Doradidae (thorny catfishes). We quantified morphological diversity using three-dimensional geometric morphometrics and estimated evolutionary rates, shifts between adaptive regimes, and evolutionary modularity and integration differences among families. We found that doradoids diversified into nine adaptive regimes across morphospace. We also found some significant differences in modularity and integration between families. Major morphological shifts have surprising correspondence to previously or currently recognized taxa within the Doradoidea. We found repeated, parallel evolution of body elongation across adaptive regimes, implying a role for selection in driving parallel evolution across a primary axis of shape diversification. However, modularity and integration do not necessarily shift in correspondence with shifts in morphological adaptive peaks.

Predators have evolved a variety of novel mechanisms for efficient prey location that rely on specific sensory modalities. Strike-induced chemosensory searching (SICS) is a behavior pattern common across squamate reptiles (snakes and lizards) where a series of specific searching behaviors are activated in the predator following the envenomating strike and immediate release of prey. Of all squamates, rattlesnakes (Crotalus spp.) have been studied most extensively for their SICS behavior, but field documentation of such behaviors is sparse and often lacking in detail. Our study took advantage of a wild population of Timber Rattlesnakes (Crotalus horridus) in the Ozark Mountains of northwest Arkansas. Individuals were implanted with radio transmitters as part of a larger study on the effects of supplemental rodent prey on the physiological ecology of C. horridus. From these supplemental feeding trials, we filmed n 5 10 successful episodes of SICS as rattlesnakes (n 5 7) struck, released, and relocated rodent prey. All rattlesnakes exhibited the typical phases of SICS (quiescence, searching, trailing), and though the duration of each phase did not differ, rates of tongue-flicking (RTF) and breathing significantly increased from quiescence to trailing. We noted rapid, shallow ventilation patterns in the rattlesnakes, burst-like ventilation (BLV), and propose that BLV functions to surveil volatile chemical cues in the environment. Rates of tongue-flicking are well known proxies for measuring vomerolfaction in squamates, and we suggest BLV may similarly serve as a proxy for estimating rates of olfaction. The short cycles of air exchange we quantified as BLV flush air across the olfactory epithelium and thus could serve to detect volatile chemical cues. Quantification of BLV may enable researchers to capture more information about the sensory processes involved in squamate foraging behavior.

Reliable length frequency distributions are useful tools for the assessment and management of fish populations. However, in situ estimation of fish length with single-camera video systems may be inaccurate. The use of allometric changes of eye diameter (ED) and head height (HH) was proposed as a promising technique to estimate fish length from single-camera footage. However, the method, so far, has proven to be effective for a limited number of species and families, and the replicability among taxa remains uncertain. We described the allometric patterns of eye diameter and head height for a set of Osteichthyes and Chondrichthyes bearing heterogeneous morphological, taxonomical, and habitat-type features from northern Patagonia, Argentina. To assess the usefulness of the method, we regressed fish length on the HH:ED ratio for each of 12 common species by using artificial neural network models and compared the results with those obtained by standard regression models. We found relevant variability in allometry among the species analyzed and described four general cases. Furthermore, artificial neural network models outperformed conventional regression, although both models converged to similar results for several species. Overall, our findings highlighted the utility of the allometry method and suggested an association of both allometric patterns and model performance with fish morphology and habitat type. Whereas osteichthyan reef species were highly suitable for using this technique, models obtained for chondrichthyans and fusiform body-shaped species were less accurate. Our findings have practical implications for the estimation of fish length using single-camera systems and provide a framework to understand the differential suitability of the allometric approach.

In the tadpoles of some anuran species, there is a set of one or more anterior labial tooth rows that are divided by the upper jaw sheath, which we call paraoral tooth rows. We studied the taxonomic distribution of these tooth rows based on published information and preserved specimens in 4,595 species of anurans from all currently recognized families. Paraoral rows were recorded in 594 species, most belonging to Ranoides and Anomocoela, but also occurring in Myobatrachoidea and a few notogaeanurans. The reconstruction of ancestral states indicated at least 15 independent origins of the character state during the evolutionary history of the anurans. The paraoral rows are a typical character of Anomocoela and Ranoides. The presence of paraoral rows was retained in both clades during their evolutionary history when specialized morphologies evolved, as long as labial teeth were not lost.

When multiple species within an ecological community are all threatened or endangered, it may be crucial to understand the interconnected relationships of populations in order to better inform their individual recovery plans. We examined the potential egg predation of the critically endangered Leon Springs Pupfish (Cyprinodon bovinus) endemic to the Diamond Y Spring system in West Texas. This one spring-fed pool also includes multiple species of invertebrate animals and another endangered fish, the Pecos Gambusia (Gambusia nobilis). Artificial mats were used to observe individual eggs laid by promiscuous females within the defended territories of various males. These eggs were then monitored over a 24-hour period, with and without protection from nocturnal predators. Analysis revealed that predation of eggs is occurring both diurnally and nocturnally, and examination of the pattern of egg predation suggests that this egg predation is a result of multiple species of predators. The number of eggs at the beginning of the observation period was significantly correlated with the number not preyed upon and present following 24 hours, suggesting that males should be investing considerably in spawning with females to increase their reproductive output. Further study is needed to understand the impact that egg predation is having on the reproductive success of this endangered pupfish.

The relationships of Guiana Shield members of Trichomycterus are examined using three mitochondrial genes (Cytochrome Oxidase 1, Cytochrome b, and 16s) and one nuclear gene (RAG 2). A time-calibrated phylogeny is implemented to examine how diversification is related to the timing of major geographical events in the Guiana Shield. There was topological discordance among the gene trees; however, they overall suggest the presence of two subclades. The T. guianensis subclade consists of the strongly supported relationships of T. sp. ‘Potaro, elongate’ (Potaro R.) sister to T. guianensis (Potaro R.) + T. sp. ‘Ireng, spotted’ (Ireng R.). The T. cf. guianensis subclade consists of the strongly supported sister group relationship of T. cf. guianensis (Mazaruni, Potaro, and potentially Caroni Rivers) + T. sp. ‘Mazaruni, plain’ (Mazaruni R.). Weakly supported as sister to this is T. sp. ‘Kusad Mountain’ (Takutu R.), and sister to all other members of the subclade is T. conradi (Ireng and Potaro Rivers). The dated phylogeny suggests that the Guiana Shield clade is derived from a lowland ancestor that entered the Proto-Berbice and/or Proto-Essequibo Rivers ∼17.4 Ma. The Proto-Berbice contained the lowland portions of the Ireng and Takutu Rivers, and the Proto-Essequibo contained the lowland portions of the Potaro and Mazaruni Rivers, but the histories of the upland portions of the Ireng, Potaro, and Mazaruni Rivers are less clear and have been thought to have drained northward in what we are referring to as the Grand Pakaraima River in which all members of the T. guianensis clade (except for T. sp. ‘Kusad Mountain’ and possibly T. conradi) were found. We interpret two geodispersal events into the Grand Pakaraima River and a potential vicariance event ∼9.4 Ma between uplands and lowlands. The likely formation of the modern Guiana Shield rivers occurred 3.8–1.9 Ma, with the modern Ireng River being captured first by the Proto-Essequibo ∼3.8 Ma and finally consolidated ∼1.9 Ma when captured by the Rio Branco.

The joint American Fisheries Society and American Society of Ichthyologists and Herpetologists Committee on Names of Fishes has updated the list of the species of fishes in the three countries of North America. This contribution provides succinct analyses of the changes in these data over the eight editions, for example, the discovery of new species and exotic species, as well as the conservation status of the fishes in the three countries and by habitat. There are 5,089 species of fishes in North America: 1,254 in Canada, 3,821 in the United States, and 3,261 in Mexico; 107 of them are introduced established species and 37 are extinct.

El Comité sobre Nombres de Peces, un comité conjunto de la Sociedad Americana de Pesquerías y la Sociedad Americana de Ictiólogos y Herpetólogos, ha publicado la última edición de la lista de especies de peces en los tres países de Norteamérica. Esta contribución ofrece análisis sucintos de los cambios a lo largo de las ocho ediciones, por ejemplo el descubrimiento de nuevas especies y de especies exóticas, así como el estado de conservación de los peces, en los tres países y por hábitat. Hay 5089 especies de peces en Norteamérica: 1254 en Canadá, 3821 en los Estados Unidos, 3261 en México; 107 de ellas son especies introducidas establecidas y 37 están extintas.

Le Comité sur les Noms des Poissons, un comité conjoint de la Société Americaine de Pêcheries et de la Société Americaine des Ichtyologistes et Herpetologistes, a publié la dernière édition de la liste des espèces de poissons dans les trois pays de l'Amérique du Nord. Cette contribution fournit des analyses succintes des changements survenus au cours des huit éditions, par exemple la découverte d'espèces nouvelles et d'espèces éxotiques, ainsi que l'état de conservation des poissons, dans les trois pays et par habitat. Il y a 5089 espèces de poissons en Amérique du Nord: 1254 au Canada, 3821 aux ÉtatsUnis, 3261 au Mexique; 107 d'elles sont des espèces introduites établies et 37 sont éteintes.

The taxonomy of the genus Phenacogaster is reviewed in Colombia, and nine species are recognized in the country. This study includes the description of four new species using morphological data. The new species are: Phenacogaster yari, new species, from the Amazon River basin that differs from its congeners by the combination of an incomplete lateral line, the relative posterior position of the humeral spot, 29–32 branched anal-fin rays, six gill-rakers on the lower limb of the first gill arch, presence of bony hooks on pelvic-fin rays of males, absence of hooks on pectoral-fin rays of mature males, and a relatively shorter standard length (adult males with 25 mm SL); Phenacogaster nukak, new species, from the Orinoco River basin that differs from the other species by the combination of an incomplete lateral line, humeral spot far from the psedotympanum, 8–11 perforated scales in the lateral line, 29–30 teeth in the maxilla, 32–34 branched anal-fin rays, body height 28.8–43.3% SL, and pre-ventral length 37.4–41.7% SL; Phenacogaster tukano, new species, from the Amazon River basin that differs from the other species by the posteriorly displaced humeral spot and a complete lateral line; and Phenacogaster guayupe, new species, from the Orinoco basin is recognized by an incomplete lateral line, a large and round humeral spot near the pseudotympanum in females with width greater than half the ocular diameter, 2–3 large tricuspid teeth in the outer row of the premaxilla, and a pre-ventral length 36.4–43.3% SL. A taxonomic key for the identification of species is provided, together with distribution maps of all species in the genus in Colombia.

The Gymnotiformes, or electric knifefishes, is a clade of freshwater ostariophysan fishes native to tropical South and Central America that are easily recognized by the presence of an elongate body and elongate undulating anal fin, and lack of dorsal and pelvic fins. In this study, we report on unusual specimens of the Black Ghost Knifefish Apteronotus albifrons (Apteronotidae) exported from Asian aquaculture facilities, which exhibit a fin located on the median dorsal surface. This fin exhibits the distinctive ball-and-socket articulating joint between the fin rays and pterygiophores otherwise only observed in gymnotiform anal fins and differs from the laterally restricted dorsal-fin-pterygiophore articulation of other ostariophysan taxa. We interpret the dorsally located fin of these specimens of Apteronotus albifrons as an ectopic expression of a median fin with an anal-fin phenotype and do not interpret the dorsally located fin as representing the reappearance of the plesiomorphic ostariophysan dorsal fin. The anterior–posterior position of the dorsally expressed fin corresponds closely with that of the dorsal organ, a fleshy electroreceptive structure that lies along the dorsal body margin of other apteronotids. This topological concordance implies the presence of a conserved embryonic tissue underlying development of both the dorsal organ and the dorsally expressed median fin.

Anthropogenic activities can increase contaminants in aquatic environments. These pollutants can have negative consequences for aquatic taxa, particularly amphibians, because of their permeable skin and biphasic life cycle. Water pollution is contributing to the global decline of amphibians, so understanding the impact of contaminants on these taxa is imperative. Glyphosate herbicides are typically formulated with a surfactant to increase effectiveness and with a soluble dye to reveal coverage. Typical formulations result in increased mortality of several amphibian species, but we do not have a good understanding for which formulation component (or components) reduce fitness. We conducted an outdoor mesocosm experiment to assess the individual and interactive effects of glyphosate, surfactant, and dye on survival, days to metamorphosis, and mass at metamorphosis of American Toads (Anaxyrus americanus). Our results showed that none of our fitness variables responded to glyphosate itself in two concentrations commonly found in contaminated freshwater habitats nor to the soluble marker dye. In contrast, survival in surfactant treatments was, on average, 6.6% compared to 81% for the control treatment, but surfactant led to larger mass at metamorphosis of larvae that did survive. These results suggest that surfactant is the main problem in glyphosate application and that formulations without the surfactant may be the best choice for riparian management.

The Devils River Minnow (Dionda diaboli) is a federally endangered species endemic to spring-fed tributaries of the Rio Grande drainage of Mexico and western Texas. Its occurrence in spring-fed stream habitats suggests that increased turbidity could negatively affect its survival in the wild. We used a laboratory experiment to assess the effect of turbidity (0 NTU: control; 10 NTU: low; 50 NTU: moderate; and 100 NTU: high) on time to initiate foraging, feed conversion ratio (FCR), specific growth rate (SGR), and condition coefficient for juvenile D. diaboli fed on a diet of chironomids, a pollution-tolerant invertebrate. Our results showed that increased turbidity significantly affected time to initiate foraging, but not the amount of food consumed, growth, body condition, and survival. Thus, although short-term exposure to turbidity conditions negatively affected feeding behavior, the treatments were not sufficient to cause significant differences in physiological performance and growth, suggesting D. diaboli may be resistant to short-term pulse increases in turbidity in its natural habitat. In this study, D. diaboli fed on chironomids had low average juvenile survivorship (27%) by the end of 12 weeks, with decreased growth and weight beginning by week 4 and 6, respectively. Thus, although increased turbidity did not directly affect D. diaboli, if elevated turbidity causes alteration of food resources toward pollution-tolerant macroinvertebrates, the species could be negatively affected. These results provide important information on the impacts of turbidity on the long-term conservation of D. diaboli, though further studies are needed to examine the species response to combined impacts of turbidity, droughts, non-native species invasions, and altered habitat.