We describe two new cryptic species of Bufo within the subgenus Anaxyrus discovered in Central Nevada of the western United States. Our analyses revealed that these two localized endemic toads are genetically divergent and morphologically distinct, yet were concealed under the range of the broadly distributed western toad (Bufo boreas), which occurs throughout Nevada. The newly discovered species are close in geographic proximity to each other (albeit, in different hydrological basins) but have evolved unique morphological characters that are distinct from each other and distinctive from all allied taxa within the B. boreas species complex. The delimiting of these two rare toads emphasizes the link between taxonomic crypsis and inadequate conservation as these newly described species are vulnerable to extinction due to severely restricted geographic ranges, unknown population sizes, and dependency on rare, fragile wetland habitat, which is a limited resource within Nevada, the primary state that makes up the arid Great Basin. These two endemics join the Great Basin B. boreas species complex as imperiled new members, and our study demonstrates that our knowledge of anuran diversity is incomplete and that new discoveries can still be made, even in unlikely settings.
The White Shark (Carcharodon carcharias) is a top predator cosmopolitanly distributed and heavily protected worldwide. Identification and information pertaining to White Shark nursery areas is limited yet crucial for the protection of sharks during their most vulnerable life stages. Here, we present morphometric, skeletal, and haplotypic characteristics of the smallest free-living White Shark reported to date (1066 mm TL). These characteristics correspond to a newborn White Shark smaller than those previously reported in an embryonic state but displaying the same number of rows of functional teeth as an adult. The individual was caught incidentally by an artisanal fishery operating along the Pacific coast of Baja California, near the international border between Mexico and the United States (USA). We found no genetic divergence between Isla Guadalupe and central California, two aggregation sites that have been proposed as a possible source for newborn sharks in this area. The newborn White Shark displayed the most common haplotype present among individuals at both aggregation sites. These findings provide evidence suggesting the presence of an extended nursery habitat in the Northeast Pacific, a transnational region between Mexico and USA.
The new species, Cirrhilabrus briangreenei, is described on the basis of the holotype and six paratypes collected from mesophotic coral ecosystems of the Verde Island Passage, Philippines, between depths of 82 and 110 m. The new species is most closely related to Cirrhilabrus pylei, but it differs primarily in the presence of: more pored scales on the posterior lateral line (7–9 vs. 5–6); a lower number of circumpeduncular scales (14 vs. 16); a lower number of gill rakers (16–17 vs. 18–20); and differences in coloration details of the dorsal and caudal fins. Both species differ from all other congeners in sharing the following combination of characters: pelvic fins very long (56.5–70.0% SL), often extending past anal-fin terminus in males; caudal fin scintillating and iridescent in males; dorsal fin with sinuous scribbling in both sexes; anterior dorsal fin with a metallic blue spot on first one to two interspinous membrane spaces; snout with three parallel stripes from maxilla to anterior edge of orbit; and rest of head with a network of short broken pinstripes in both sexes. These characters are also distributed in part amongst other species of Cirrhilabrus, in particular, C. katoi, C. lineatus, C. rhomboidalis, and C. rubrimarginatus, and their putative relationships are discussed on the basis of meristic, morphometric, and molecular sequence data. We briefly comment on the variability of morphological characters within Cirrhilabrus and their implications towards phylogenetic classification, with remarks on methods for data collection for species of Cirrhilabrus.
In southern Florida, Gopher Tortoises (Gopherus polyphemus) occupy mesic flatwoods and Florida scrub communities where habitat and climatic conditions differ from other portions of the species' range. Both of these habitats appear suboptimal for tortoises due to saturated soils in mesic flatwoods and low forage abundance in scrub. Nonetheless, these habitats support large numbers of tortoises in southern Florida, albeit at low intensities. We assessed influences of elevation and microtopography on the spatial distributions of tortoise burrows and examined burrow use patterns within six sites at Avon Park Air Force Range in south-central Florida. The six sites differed in dominant soil types and vegetation communities, allowing comparisons of burrow distributions among mesic flatwoods, Florida scrub, and mixed flatwoods-scrub habitats (two replicate sites each). Point-process modeling identified significant influences of microtopography on burrow intensities that superseded the effects of site-wide elevation trends in five of the six sites. The effects of microtopography were most pronounced in flatwoods, suggesting greater reliance on areas of slightly higher elevation in mesic habitat, presumably in response to saturated soils and frequent flooding. Burrow use patterns during an exceedingly wet year also suggested that tortoises respond behaviorally to unsuitable hydrology by moving frequently among burrows that were flooded with groundwater. Microtopographic variation may be an important predictor of small-scale habitat use for fossorial reptiles, especially in mesic soils, which could be readily explored using increasingly available LiDAR-derived elevation data combined with the modeling approach demonstrated here.
Vast differences in available resources between habitats can have profound influences on aspects of an organism's life history, such as reproductive investment. Our study investigated how differences in nutrient availability affect sperm size in Diamond-backed Watersnakes (Nerodia rhombifer). We compared body size and sperm morphometrics between two populations with differing nutrient availability: a naturally occurring lake and a commercial fish farm. We hypothesized that prey availability affects sperm morphometrics. Our null hypothesis was that there would be no significant difference in sperm morphometrics between populations, whereas our alternative hypothesis was that the snakes from the fish farm would have significantly longer sperm. We measured total sperm length, sperm head length, sperm tail length, and snout–vent length (SVL). We then used two-tailed t-tests and AIC model selection to test our hypotheses. SVL was not correlated with sperm size. Furthermore, none of the sperm morphometrics were significantly different between the two populations. Finally, a nearly 1:1 correlation between sperm tail length and total sperm length was found. AIC model selection corroborated these results by choosing only sperm head length and sperm tail length as significant predictors of total sperm length. This is the first published study to explicitly compare sperm morphometrics between two populations of the same snake species. Additional studies of this nature are required to corroborate whether lack of significant differences in sperm morphometrics among snake populations are common.
A new species of Hyphessobrycon from a tributary of the Rio Paru do Oeste (Rio Trombetas basin), at the lower Amazon basin draining the Guiana Shield region in Pará State, Brazil, is described. The new species presents a unique combination of an irregularly-shaped humeral blotch, a broad diffuse midlateral stripe, and a roughly triangular caudal peduncle blotch. The new species is herein included in the Hyphessobrycon agulha species-group, and comparisons with species belonging to this group and to a similar-looking non-congener, Hemigrammus bellottii, are presented.
Information about the life history of larval fishes can be sparse, especially at the edges of typical geographic ranges and among fishes for which there is no commercial fishery. We report a new observation of larval Arctic Shanny (Stichaeus punctatus) far south of their typical geographic range in the western North Atlantic. Only two previous records of adult of S. punctatus have been documented in this region, and there has only been one previous report of larvae in US Atlantic waters. From May through July 2018, we observed large numbers of larval S. punctatus by night-lighting off a dock at Shoals Marine Laboratory on Appledore Island, Maine, in the Gulf of Maine. We include approximations of catch per unit effort (number of larvae per ten-minute sampling interval) throughout the sampling period and information regarding identifying features. The high number of larvae seen could indicate that the Isles of Shoals is a spawning locality for this species and could indicate a future increase in their abundance in the southern Gulf of Maine.
While organisms are typically considered permanent residents of a community, many transient organisms occupy a community for only brief periods. Despite the duration, the effects of a short visit by a top predator may remain long after departure. To test hypotheses on the impacts of a short-term visit by a top predator on pond communities, we used artificial ponds and constructed food web treatments that varied in trophic structure (Control Food Web = no predators present, Bluegill Food Web = only intermediate predators present, and Full Food Web = top and intermediate predators present). The constructed food webs were replicated five times and contained two prey species (frog tadpoles), an intermediate predator (fish), and one top predator (freshwater turtle). The Full Food Web simulated a four-day visit by Chelydra serpentina (Common Snapping Turtle). Predation by Lepomis macrochirus (Bluegill) reduced mean tadpole survival for Hyla chrysoscelis (Cope's Gray Tree Frog) in all food webs, including the Full Food Web with C. serpentina, compared to the Control Food Web. Although C. serpentina had no effects on tadpoles of H. chrysoscelis, the top predator reduced mean survival and increased mean mass of Rana sphenocephala (Southern Leopard Frog) when compared to the Bluegill Food Web. Therefore, our results suggest that brief visits from transient organisms, especially top predators, can alter community structure and initiate cascading effects.
In this study, we use a geometric morphometric and a character evolution approach to study the evolutionary patterns of body-shape change and habitat transition in the Aulopiformes. Aulopiform fishes (lizardfishes; 289 spp.) inhabit diverse marine habitats from coral reefs to the deep sea and exhibit a wide range of body morphologies. Herein, we examine over 400 aulopiform specimens representing 38 of 44 genera and all families and identify that there are distinct patterns of body-shape change across the aulopiform radiation that coincide with habitat. A fusiform (torpedo-shaped) body is predominant among aulopiforms distributed in inshore-benthic and deep-sea benthic environments (e.g., Aulopidae, Bathysauridae, Synodontidae). There is a trend towards body elongation in taxa distributed in deep-sea pelagic habitats at depths of 200–4,000 meters (e.g., Alepisauridae, Lestidiidae, Notosudidae, Paralepididae) and a trend of body elongation with more centrally positioned dorsal and anal fins in the deep-benthic family Ipnopidae (tripodfishes). Additionally, deep-sea pelagic aulopiforms exhibit the largest variance in body-shape disparity with significant shape disparity compared to aulopiforms found in inshore-benthic and deep-sea environments. Deep-sea benthic lineages also have significantly higher body-shape variance and disparity compared to inshore-benthic lineages. We identify that there are considerable changes in body shape as aulopiform lineages transitioned to differing marine habitats. We infer the common ancestor of aulopiforms to have lived in a deep-sea benthic environment with a single transition to an inshore-benthic environment in the common ancestor of the Aulopoidei (lizardfishes, flagfin fishes) and two independent transitions into deep-sea pelagic environments, once in the common ancestor of Giganturidae, and once in the common ancestor of Alepisauroidea + Notosudoidea. This is the first study to quantitatively investigate changes in the body shape of aulopiform fishes tied to habitat transitions in marine environments from the deep sea to coral reefs. Our findings suggest that aulopiform body plans have broadly diversified in deep-sea pelagic and benthic habitats while remaining comparatively conservative in inshore-benthic habitats.
Nongenetic inheritance-involving epigenetic, behavioral, or environmental factors-is increasingly viewed as being important in development and evolution. Here, we describe a possible novel form of nongenetic inheritance in the tadpoles of the Mexican Spadefoot (Spea multiplicata): the transmission of information about the environment from dead individuals to living individuals of a later cohort or generation. When we exposed live tadpoles to the remains of desiccated conspecifics from a naturally occurring dry pond, we found that they used phenotypic plasticity to adjust their development in ways that would increase their chances of escaping a drying pond. Specifically, compared to their siblings that were reared with soil lacking tadpole remains, those reared with soil containing desiccated conspecifics grew larger, developed faster, and were more likely to express an alternative, environmentally induced phenotype-a distinctive carnivore morph that is favored in rapidly drying ponds. We also found evidence of underlying genetic variation in the plasticity to produce carnivores, suggesting that this plasticity could mediate adaptive evolution when populations experience different environmental conditions. Such a tendency of living individuals to respond to cues associated with dead individuals from a previous generation may be vital in giving each generation a head start in their environment.
Accurate, comprehensive data on life expectancy, growth rates, age structure, and sexual maturation are necessary to inform decision-making for conservation action, but they are often difficult to obtain from wild animals. Osteohistology has proven a reliable method for accessing chronological data in extant and extinct vertebrates. Traditional mark–recapture methods require repeated measurements in the field and do not allow comparison with far more extensive data from specimens housed in museum collections, thus reducing statistical power and inviting unjustified extrapolation. We investigate longevity and growth in the large-bodied iguanian lizard Sauromalus ater (Common Chuckwalla). We find highly variable growth to be typical for S. ater occupying a spectrum from rapid growth to sexual maturity within two to three years leading to above-average body size later in life or slow growth early in life with sexual maturity at four to eight years followed by growth to body sizes around the average adult size. We show individual S. ater achieve final body size in about ten years, not decades, and that body size and age in adults are significantly correlated. This study suggests conflicting reports on growth, maturation, longevity, and generation cycle in S. ater are all correct and reflect complex ontogeny in squamates.
We examined eye-bulging behavior in relation to scent-marking and chemosensory behavior in three species of iguanian lizards, Sceloporus jarrovii, S. tristichus, and S. virgatus, in a controlled environment. We studied males of the three species and also females of S. jarrovii and S. tristichus. Overall, the frequency of eye-bulging was positively correlated to the frequency of chin wipes in males, but not females. Chin wipes rarely occurred in the absence of eye-bulging; they were closely associated with the latter and, to some degree, to other chemosensory behavior. Of the three species, S. virgatus exhibited the highest eye-bulging frequency. The possibility of eye-bulging behavior being utilized for chemical communication is discussed.
Riverine fishes are sensitive to human-induced changes to their ecosystems and have experienced substantial declines in the past century. The presence and operation of dams modifies natural flow regimes thereby disrupting cues that signal migration and negatively influencing habitats critical to riverine fishes. Blue Suckers (Cycleptus elongatus) make large annual movements, require large and unfragmented reaches of river, and may be sensitive to modifications of cues that initiate migration. We assessed the influence of individual and abiotic factors on home ranges and movements of 62 transmittered Blue Suckers from 2006-2014 in the Missouri River upstream of Fort Peck Reservoir in Montana. Populations in this area are disjunct from those downstream and are influenced by upstream dam regulation. Blue Suckers used large expanses of river with overall home ranges similar to 88 river kilometers, but these home ranges were about two times smaller than reported elsewhere. Increasing discharge and water temperature were associated with movement rate and movement probability and cued spawning movements of Blue Suckers. Movement rates increased with discharge to peak and decreased thereafter. Surprisingly, movement rate and probability were highest at the lowest water temperatures we observed (similar to 1-58 degrees C) unlike previous studies in other systems when peak movement occurred at >= 10 degrees C. Blue Suckers aggregated and showed interannual fidelity to several locations during spawning. Aggregation and fidelity suggest that optimal spawning areas, which exist in tributaries, may be limited within our study area. Our results support evidence that riverine fishes require natural trends in discharge and water temperature, including occasional flood pulses and connectivity among seasonal habitats. The Upper Missouri River retains pseudonatural discharge and temperature regimes that elicit responses of Blue Sucker to environmental cues, but other rivers may not. Preserving or restoring these features, and entire riverscapes, would maintain natural environmental cues and habitats required by riverine fishes to complete their life histories.
A second species of Acanthobunocephalus is described from tributaries of the lower Purus River in the Amazon Basin, Brazil. Acanthobunocephalus scruggsi, new species, is distinguished from all other aspredinid species by its reduced number of fin rays: four pectoral-fin rays (vs. five or more), two dorsal-fin rays (vs. three or more, except Amaralia hypsiura), five pelvic-fin rays (vs. six), four to five anal-fin rays (vs. six or more, except Bunocephalus verrucosus), and nine caudal-fin rays (vs. 10, except Hoplomyzontinae, Amaralia, Platystacus, Bunocephalus chamaizelus, and Bunocephalus minerim). Osteological aspects of the new species of Acanthobunocephalus are described using cleared and stained specimens and high-resolution x-ray computed tomography (HRXCT), and compared with Acanthobunocephalus nicoi and other aspredinids. Generic assignment is based on putative apomorphic shared features and a morphological diagnosis for Acanthobunocephalus is presented.
L ESLIE WILLIAM KNAPP was born in Auburn, New York on November 17, 1929 and died May 17, 2017 in Maryland. He graduated from Port Byron Central School, Port Byron, New York in 1947. Les is survived by his wife Betty who runs a greenhouse business, Loch Less Farm, and their two sons. Les entered the College of Agriculture of Cornell University in September 1948 and received his B.S. degree in 1952. He enlisted in the U.S. Army and served from 1952 to 1954. He entered the University of Missouri in February 1955 and completed his master’s degree in August 1958, ‘‘A distributional study of the fishes of the upper White River, Missouri,’’ studying under Arthur Witt, Jr. In September 1958 he began his ichthyological studies under Edward C. Raney at Cornell University and received his Ph.D. degree in February 1964 studying the systematics of the Rainbow Darter, Etheostoma caeruleum. This was a busy time for darter studies at Cornell with Robert V. Miller, William Richards, and me all studying different groups of darters under the guidance of Edward Raney. From Cornell, Les was hired by the Smithsonian Oceanographic Sorting Center in Washington, D.C., which was just getting started, to process material collected by expeditions such as the International Oceanographic Campaign. Les published seven studies on darters from 1963 to 1976, including joining me to produce a catalog of all type specimens of all the darters (Collette and Knapp, 1967). Les then turned his efforts to studying two families of marine fishes, the flatheads, Platycephalidae and Bembridae, publishing 24 papers from 1973 to 2012, seven with Hisashi Imamura from Japan. He also completed the sections on Bembridae and Platycephalidae which are still in press in the long-delayed volumes of Fishes of the Western Indian Ocean (Table 1).
Given the conservation status and ecological, cultural, and commercial importance of chondrichthyan fishes, it is valuable to evaluate the extent to which research attention is spread across taxa and geographic locations and to assess the degree to which scientific research is appropriately addressing the challenges they face. Here we review trends in research effort over three decades (1985–2016) through content analysis of every abstract (n = 2,701) presented at the annual conference of the American Elasmobranch Society (AES), the oldest and largest professional society focused on the scientific study and management of these fishes. The most common research areas of AES abstracts were reproductive biology, movement/telemetry, age and growth, population genetics, and diet/feeding ecology, with different areas of focus for different study species or families. The most commonly studied species were large and charismatic (e.g., White Shark, Carcharodon carcharias), easily accessible to long-term established field research programs (e.g., Lemon Shark, Negaprion brevirostris, and Sandbar Shark, Carcharhinus plumbeus), or easily kept in aquaria for lab-based research (e.g., Bonnethead Shark, Sphyrna tiburo). Nearly 90% of all described chondrichthyan species have never been mentioned in an AES abstract, including some of the most threatened species in the Americas. The proportion of female* first authors has increased over time, though many current female* Society members are graduate students. Nearly half of all research presented at AES occurred in the waters of the United States rather than in the waters of developing nations where there are more threatened species and few resources for research or management. Presentations based on research areas such as paleontology and aquarium-based research have declined in frequency over time, and identified research priorities such as social science and interdisciplinary research are poorly represented. Possible research gaps and future research priorities for the study of chondrichthyan fishes are also discussed.
Target enrichment of conserved nuclear loci has helped reconstruct evolutionary relationships among a wide variety of species. While there are preexisting bait sets to enrich a few hundred loci across all fishes or a thousand loci from acanthomorph fishes, no bait set exists to enrich large numbers (>1,000 loci) of ultraconserved nuclear loci from ostariophysans, the second largest actinopterygian superorder. In this study, we describe how we designed a bait set to enrich 2,708 ultraconserved nuclear loci from ostariophysan fishes by combining an existing genome assembly with low coverage sequence data collected from two ostariophysan lineages. We perform a series of enrichment experiments using this bait set across the ostariophysan tree of life, from the deepest splits among the major groups (>150 Ma) to more recent divergence events that have occurred during the last 50 million years. Our results demonstrate that the bait set we designed is useful for addressing phylogenetic questions from the origin of crown ostariophysans to more recent divergence events, and our in silico results suggest that this bait set may be useful for addressing evolutionary questions in closely related groups of fishes, like Clupeiformes.
In freshwater turtles, movements have been shown to be influenced by seasonal changes in water levels, with members of the family Podocnemididae exhibiting some of the longest nesting migrations yet documented. In this study, we quantified linear home range sizes and seasonal movements of the Magdalena River Turtle (Podocnemis lewyana) using capture–mark–recapture and radio-telemetry techniques. We marked 924 turtles and recaptured 7.8% of these individuals one or more times, thereby documenting the movements of 41 juveniles, 13 males, and 18 females. Turtle movements differed significantly among sex/size classes, with males moving more. While 85% of all individuals had estimated linear home range sizes of less than 1 km, one juvenile moved 3.1 km, one female moved 2.5 km, and one male moved 4.8 km. We also obtained data on the movements of six reproductively mature females using radio telemetry. We documented seasonal movements out of channels into wetland or riverine habitats, increasing the estimates of total distance traveled for this sex/size class to a mean of 13.8 km (range = 6.9–18.7 km), with greater displacements documented during low water periods. Together, our results show that individuals of P. lewyana in the middle Magdalena River drainage occupy limited linear home ranges, but that reproductively mature females make extensive displacements during low water periods, presumably related to their need to access nesting beaches in riverine habitats. There are currently no protected areas within the range of this endemic species, but our results argue that any reserve created for protecting this critically endangered turtle must be large enough to cover all of its habitat requirements, including nesting beaches in the dry season that are separated from habitat where they maintain stable home ranges during the remainder of the year.
