This paper describes direct video observations of two manefishes, likely Paracaristius sp., from the mesopelagic waters of the north-central Gulf of Mexico. One fish was observed with a remotely operated vehicle at a depth of 829 m by an industrial ROV as part of the SERPENT Project. The second was observed at 496 m from a manned submersible. Little is known about the behavior of manefishes because most records result from net-collected material. Our observation demonstrates that manefishes are capable of precise locomotory and posture control using extended, erect fins and that the pelvic fins of these fishes are extended in a parachute-like manner. Moreover, one of the specimens exhibited an unusual vertical, sinusoidal oscillation of its caudal fin. One of the observations took place in association with a physonect siphonophore. These observations may include the deepest published record for a manefish in the Gulf of Mexico.

Interspecific competition for resources is predicted to be high in dense populations of closely related species and should lead either to species partitioning resources along one or more niche axes, or exclusion of the competitively inferior species. Between 19 June and 19 July 2003, we collected 71 recently metamorphosed Rana areolata (Crawfish Frogs) and 69 recently metamorphosed R. sphenocephala (Southern Leopard Frogs) from a single pond in northeastern Oklahoma and compared their morphology and diet. We found that recently metamorphosed R. areolata and R. sphenocephala are morphologically similar. Further, diets of both species were similar: hemipterans predominated, prey items were similarly sized, and dietary niche breadths overlapped, but R. areolata had significantly lower volumes of prey in their stomachs. Because of the high risk of desiccation, especially in Great Plains populations, newly metamorphosed Rana are not expected to disperse far from their natal ponds. During this first season, Rana also experience rapid growth. Dietary restrictions directly influence growth rate, which in turn are known to have major consequences during later life stages, ultimately affecting fitness. Rana areolata is a species of conservation concern across its range. Competitive interactions with other species of Rana have been proposed to be contributing to declines in R. areolata. Our results indicate that competitive interactions with R. sphenocephala have the potential to negatively affect prey consumption, and ultimately fitness, in R. areolata.

Historically, the Eastern Box Turtle (Terrapene c. carolina) was found in 31 counties in Michigan's Lower Peninsula, although it has been extirpated from 13 of those counties in the last ten years. One possible cause of the decline is road-based habitat fragmentation with resulting demographic and genetic consequences. Accurately identifying population structure is necessary to determine conservation units and aid in the recovery of Terrapene c. carolina. We genotyped 163 turtles at eight microsatellite loci from three locations in southwestern Michigan covering 360 km². We found high levels of genetic variation (H  =  0.83; A  =  16) and low levels of genetic differentiation (F_ST  =  0.006) in the system. The three areas exist as a single population and there was a low rate (11%) of misassignment across the sites. There was initial evidence of a genetic bottleneck in two of the three populations and the system as a whole. However, additional analysis failed to find a mode-shift in allele frequencies and did not detect any further evidence of a bottleneck in any of the populations. We conclude that the conflicting genetic indication of a bottleneck, despite the geographic evidence, is due to the long generation time of Terrapene c. carolina. Further, our study suggests that the retention of genetic variation despite population declines allows managers flexibility in dealing with the conservation of long-lived species.

The pathogenic chytrid fungus Batrachochytrium dendrobatidis, typically associated with anuran amphibians, is present in natural populations of the terrestrial salamander, Batrachoseps attenuatus, from California, USA, and four congeners from California and Oregon, USA. I demonstrate that the chytrid has been present in wild populations of B. attenuatus since at least 1973, and while infected salamanders collected in the wild exhibited 100% mortality in the laboratory, wild populations appear to have remained stable with seasonally variable infection rates. Laboratory experiments showed that inoculated salamanders housed in dry microhabitats, mimicking summer aestivation conditions, are able to shed the chytrid infection. Combining these data with the decrease in prevalence from spring to fall suggests that environmental conditions in the natural range of B. attenuatus mediate the effects of this potentially highly lethal pathogen, stabilizing this host–pathogen relationship. While B. attenuatus continues to be an abundant salamander, other amphibians are experiencing marked declines. An understanding of the relationship between the amphibian chytrid fungus and species of Batrachoseps may be applicable to patterns of declines and persistence in other species of plethodontid salamanders, and amphibians in general.

When molecular phylogeography results in the discovery of hidden diversity, this diversity is often labeled as cryptic. Few studies have gone back to the morphology to determine whether or not this molecular diversity is in fact detectable at the morphological level. The Notropis rubellus species complex has a widespread distribution in freshwater streams of eastern North America. Recent molecular studies have identified up to seven allopatric clades, suggesting that there may be morphologically cryptic diversity within the group. This study uses traditional meristics and geometric morphometric methods to test molecular hypotheses of cryptic diversity within the species complex. Meristic data and a principal component analysis of geometric morphometric data supported the cryptic hypothesis. Canonical variates analyses (CVA), however, were able to detect statistically significant, clade-specific morphological variation, suggesting that in this case, cryptic diversity was an artifact of the detection method. CVA thus provided a useful tool for identifying subtle or complex shape variation. However, morphological variation within the N. rubellus species complex was undetectable without a pre-existing molecular hypothesis.

We describe a new species of tree frog related to the Bokermannohyla circumdata group, the northernmost record from Atlantic Forest remnants in eastern Bahia, northeastern Brazil, within regions known as Vale do Jiquiriçá, Baixo Sul, and Litoral Sul. The new species is diagnosed by medium size (snout–vent length 46.8–64.1 mm), head longer than wide, small tympanum, posterior surfaces of thighs with dark brown transverse stripes without additional thin stripes between them, vocal slits in adult males, and distinct advertisement call with a single note composed of 30–110 pulses distributed within 2–9 pulse groups, similar to the bleating of a goat. The new species is morphologically similar to B. hylax and B. lucianae, but is readily distinguished by the presence of barred posterior surfaces on the thighs without thin stripes between them (immaculate in B. lucianae; thin stripes intercalated with wider stripes in B. hylax) and by its distinct vocalization.

A new species of Corydoras from the Rio Urucu basin, a right-bank tributary of the Rio Solimões is described. The new species shares a distinctive pigmentation pattern with Corydoras arcuatus, C. gracilis, and C. narcissus, composed of a uniform light ground color on the body, and a dark, arched stripe from tip of snout to caudal-fin base along the upper portion of the dorsolateral body plates. The new species is readily distinguished from these congeners by the absence of a continuation of the arc-like stripe onto the snout. It also differs from Corydoras gracilis and C. narcissus by the posterior part of the arc-stripe reaching the base of the lower caudal-fin rays, and from C. arcuatus and C. narcissus by the distinctly rounded profile of the snout in lateral view, a greater preadipose distance, and the position of the posterior limit of the cleithrum. Despite the general resemblance, investigation about the position of the new species in light of previous phylogenetic hypotheses concerning this subfamily indicates that the arc-striped coloration pattern was independently acquired.

We describe a new species of scandent/arboreal frog from Sudest Island, Louisiade Archipelago, off the southeastern tip of New Guinea that exhibits a remarkable ontogenetic change in color pattern. Juveniles are shiny black with lemon-yellow spots; adults are uniform peach with bright blue eyes. We detail the ontogenetic changes in color-pattern elements that comprise this transformation. This ontogenetic change, uniform peach adult coloration, and blue iris all appear to be unique features within the genus Oreophryne, most of whose members are tan, brown, or gray. We presume the striking juvenile color pattern to serve an aposematic function, but this conjecture requires testing. The new species is restricted to a relatively small patch of cloud forest perched on the highest peak of Sudest Island. Climate change may pose a threat to the new species if changing rainfall or temperature regimes result in the loss of this forest.

During two nesting seasons we monitored 19 naturally incubated nests of Podocnemis lewyana obtained from two sites in the Mompos Depression of northern Colombia. We incubated another nine nests in the laboratory under similar humidity conditions, but at six different temperatures. We sexed the hatchlings obtained from all nests to confirm for the first time the occurrence of temperature-dependent sex determination in this species and quantify sex ratios and the pivotal temperature for this population. In both nesting seasons, the majority of the nests in the field produced hatchlings of both sexes, but sex ratios differed between study beaches/years. The pivotal temperature documented (33.4°C) appears to be among the highest reported for a turtle species. Incubation conditions in the naturally incubated nests also influenced hatching success rates and incubation periods, but not hatchling size or weight. Hatchlings obtained from the nests incubated in the laboratory were reared for one month in order to study the influence of pre-hatching factors on growth rates. In these nests we documented maternal effects on egg size, initial hatchling size, and weight and growth rates. Incubation temperature also influenced hatching success rates, sex ratios, growth rates, and hatchling size, but not hatchling weight.

Pogonophryne stewarti, new species, is described from collections made at 1700 m on the continental slope of the Indian Ocean Sector of the Southern Ocean, off Wilkes Land, Antarctica. The new species is assigned to the unspotted P. albipinna species group and is related to P. immaculata. It is distinguished from all other species of the P. albipinna species group by the following combination of characters: a long (about 15–20% SL) mental barbel without a terminal expansion, a shallow head and slender trunk with only slight taper to caudal peduncle, 8–13 middle lateral-line pores, and divergence in the mitochondrial ND2 gene. We discuss the composition and validity of the P. albipinna group, which, up to this point, has been based on three holotype specimens. We provide meristic and morphometric data for seven recently collected adult specimens of P. immaculata. Bayesian analyses of mitochondrial gene sequences for 11 of the now 19 recognized species of Pogonophryne, sampled from all five of the proposed species groups, resulted in reciprocal monophyly of the monotypic species groups. The P. albipinna and P. mentella species groups were each monophyletic and resolved as sister lineages. We provide a revised key for the four species of Pogonophryne classified in the P. albipinna group.

I investigated the contributions of several life-history traits to small body size in the two smallest species of the genus Desmognathus, D. aeneus and D. wrighti. The research was conducted in the southern Nantahala Mountains of western North Carolina, where the two species co-occur and are similar in body size and life history. Desmognathus ocoee, the next-smallest species in the local Desmognathus assemblage of six species, served as a reference species. All three species have similar juvenile growth rates. Desmognathus aeneus and D. wrighti have smaller propagule sizes (i.e., egg and hatching sizes) and higher developmental rates to sexual maturation than D. ocoee. These two factors, especially the latter, appear to explain much of the difference in adult size between D. ocoee and both D. aeneus and D. wrighti. Thus, miniaturization in D. aeneus and D. wrighti may be mainly a product of acceleration in developmental rate. I suggest that body size itself, rather than other, correlated life-history traits, has been the target of selection in these two species, in response to ecological opportunities for small salamanders in the mesic forests of the southern Appalachian Mountains.

Intraspecific competition during the larval stage has important consequences on growth and development resulting in fitness loss at higher densities in many anuran species. Larvae of Crinia georgiana can complete metamorphosis without feeding, which may make the effects of intraspecific competition potentially less significant in this species. The aim of this experiment was to determine if intraspecific competition occurs and results in fitness loss in larvae of C. georgiana. Larvae were raised at high and low densities in mesocosms in the laboratory that simulated natural ponds in the field. Offspring at higher densities metamorphosed at significantly smaller sizes and suffered higher mortality rates than larvae in the low density treatment. Despite this species possessing an egg with a large yolk content in comparison to most anuran species with exotrophic larvae, and having the ability to complete metamorphosis without feeding, intraspecific competition results in important density dependent fitness loss in larvae of C. georgiana when food resources are present.

The tuatara, Sphenodon punctatus, is known to exhibit a male-biased sexual size dimorphism, often attributed to the territorial behavior of males. Our data based on preserved specimens from museum collections also show a previously undocumented dimorphism in head and limb shape in Sphenodon, with males having bigger heads and longer limbs for a given body size than females. A review of the existing literature on the ecology and behavior of these animals suggests that this may provide males with a greater sprint speed capacity relevant to territory defense. Differences in head shape, on the other hand, may be related to ecological niche differentiation as males have been suggested to eat larger prey than females, but this remains to be tested. An additional role for sexual selection in driving the divergence in head shape between males and females is likely but cannot be confirmed at present.

Scorpaeniform fishes of the family Liparidae (snailfishes) are anatomically distinctive, morphologically variable, ecologically diverse, and globally distributed. Liparids have both boreal and austral centers of diversity; they are one of the most speciose fish families in the North Pacific Ocean, and are the most speciose fish family in the Antarctic Southern Ocean. In a previous communication we described the nervous and sensory systems of Paraliparis devriesi from the Ross Sea of Antarctica. Our goal with the present communication is to expand and generalize these findings by examining the nervous and sensory systems of two North Pacific/sub-Arctic species, P. pectoralis and P. ulochir, which live along the northwestern coast of North America and in the Bering Sea. We find that the brains and sensory systems of all three species are grossly similar, more similar to each other than to species outside the family. These brains are derived. In response to the cold and dark conditions of the deep sea, species of Paraliparis have an augmented olfactory system, a large cephalic lateral line system, an enhanced trunk somatosensory system, and an enlarged motor coordination (cerebellar) system. But they also have a reduced, rod-only visual system, a highly reduced trunk lateral line system, and have lost some portion of the higher order processing networks for these systems (in the tectum, telencephalon, and inferior lobes). It is these reductions that give the overall impression (confirmed by outgroup comparison) that the brains of these species are comparatively small. The genus Paraliparis represents a successful evolutionary lineage by the criteria of both species diversity (106 currently described species) and distribution (global, among deep-sea [>200 m] marine environments). This evolutionary success appears to be tied to the ability to inhabit the deep-sea, the world's largest living space. For Paraliparis, the loss of brain mass is one tradeoff for occupying the world's largest habitable space and the evolutionary advantages this confers.

Populations of the Desert Massasauga Rattlesnake (Sistrurus catenatus edwardsii) have declined rapidly as desert grassland communities have become reduced and fragmented. To provide information useful for management of remaining populations, the genetic characteristics (based on microsatellite DNA loci) of the last demonstrably extant population in the state of Arizona were compared to a population in the Rio Grande Valley of New Mexico. Results indicated that genetic diversity was relatively high in both populations, with statistically significant heterozygote deficiencies detected at only one of six loci in each population. Contingency tests, Wright's F-statistics, and Bayesian clustering algorithms all indicated substantial subdivision between populations in Arizona and New Mexico, but only contingency tests supported differentiation within the Arizona population. A preliminary hierarchical analysis of variance (incorporating both our data and published microsatellite data for the Eastern Massasauga) indicated that 73% of the total molecular variance was explained by variation within populations, with variation between the two subspecies accounting for 15% of the total variance. Results support the high conservation value of individual populations, as well as the need for further population genetic studies of the Desert Massasauga Rattlesnake.

Ephemeral pools are traditionally considered to be tadpole refuges, with few or no predators. While it is recognized that some tadpoles are predaceous, little attention has been given to understanding how tadpoles shape age and size structures of populations and the composition of tadpole assemblages. I examined the incidence of intraguild predation (IGP) among three species that co-occur in ephemeral pools in the Osa Peninsula, Costa Rica. I found a high incidence of IGP among the three species, with IG predators differing in their voracity for prey eggs and IG prey differing in their vulnerability to IGP. I also examined the factors that influence the intensity of cannibalism and tadpole performance in a model species, Smilisca phaeota. I manipulated predator and prey size and developmental stage, tadpole density, food quantity, and tadpole relatedness in microcosm experiments. Cannibalism in S. phaeota was dependent on tadpole predator and prey size and developmental stage, with medium and large tadpoles causing almost complete mortality of embryos, but little mortality of mobile hatchlings. In contrast, predation by small tadpoles was restricted primarily to the embryo developmental stage. Tadpole mortality was high in low plant food quantity treatments, suggesting a high incidence of cannibalism. Other measures of tadpole performance, including survival to metamorphosis, metamorph mass, and larval period, were influenced by tadpole density and plant food quantity. Additions of conspecific prey eggs and degree of tadpole relatedness did not affect tadpole performance. My results suggest that tadpoles are capable of playing a regulatory role, influencing the relative abundance and composition of species in pools through differential IGP and cannibalism on eggs and hatchlings. The intensity of IGP in ephemeral pools is likely influenced by the morphology of IG predators, reproductive mode and fecundity of IG prey, and priority effects. My study supports the view that we need to reconsider the position tadpoles occupy within the aquatic food webs, with greater appreciation for their role as predators.

Hybridization is an evolutionarily important process with varied outcomes that depend on interacting factors of time since common ancestry, behavioral differences, and environmental conditions. Hybridization is relatively common in teleost fishes, and patterns from naturally occurring hybrids and experimental interspecific crosses provide insight into the evolution of reproductive barriers that lead to speciation. It has been several decades since records of hybrid darter specimens (Percidae: Etheostomatinae) have been collected and analyzed. We assembled a dataset of 252 reported natural hybrids from museum collections and literature reports that comprise 67 unique hybrid combinations involving 63 darter species. Frequencies of unique hybrid combinations decrease with phylogenetic distance and are lower between species with different egg deposition behaviors. Large range size and egg burying reproductive behavior were characteristics of the species most frequently identified as a parental species of hybrid specimens. Evidence of genetic introgression was not consistently predicted by the frequency of records for a particular hybrid combination. This dataset likely underestimates the amount of hybridization that has occurred among darter species, because of the relatively narrow evolutionary time frame during which specimens have been collected and identified.

Studies on geographic variation in reproductive characteristics can contribute to an understanding of the effects of environmental factors on animal population structure and dynamics. Using a ten-year mark–recapture data set (1994–2003), we studied microgeographic variation in reproductive characteristics (body condition, growth, age to maturity, pregnancy interval, fecundity, and size of offspring) among three Western Rattlesnake (Crotalus oreganus) populations within 40 km of each other. Significant differences existed among snakes from the different den sites in length, body condition, growth rate, fecundity, and size and body condition of offspring. Furthermore, there was a consistent pattern in the variation among populations. Individuals from the population in the most disturbed area, were shorter, had lower body condition, grew slower, had lower fecundity, and had shorter and lower body condition offspring compared to other populations. The results from this study have important applied implications for understanding fine scale variation in reproductive characteristics. This study suggests that some rattlesnake populations have reproductive characteristics that may make them more susceptible to future disturbances.

Because many species of semi-aquatic turtles have specific habitat requirements and unique life history characteristics, they are particularly vulnerable to anthropogenic habitat modification. The federally threatened Bog Turtle (Glyptemys muhlenbergii) requires specialized wetland habitats, such as bogs and fens, in the eastern United States and often occurs in isolated populations. To develop a more a detailed understanding of the habitat use, movement, and thermal biology of Bog Turtles, we radiotracked and monitored the temperatures of 11 adult Bog Turtles at an isolated Piedmont meadow bog in North Carolina from May 2007 to March 2008. We found that turtles used soft, shallow mud habitat in the bog, but moved to a streambed when the bog became dry. While in the bog, turtles were often found within or underneath woody debris. Although most turtles resided exclusively in the southern part of the bog and the stream, two male turtles made substantial over-land movements away from the bog exceeding 130 m. All but one turtle overwintered in a streambed adjacent to the bog. Turtles overwintering within stream habitat were not exposed to temperatures below 0°C, but one turtle that overwintered in the bog did reach below-freezing temperatures. This study suggests that high-quality bog habitat and habitat heterogeneity are critical for populations living in isolated and dynamic habitats. However, maintenance of corridors between suitable habitats may be necessary for the long-term survival of Bog Turtle populations.

The testes of Hemidactylus turcicus are composed of seminiferous tubules lined with continuous germinal epithelia in which multiple germ cell morphologies can be found during the active months of sperm development. Spermatogenesis is quiescent during September, with only spermatogonia A and spermatogonia B present in the seminiferous epithelia and minimal mitotic activity is observed. Recrudescence begins in October and the early stages of spermatogenesis progress through November. The onset of spermiation is observed in December and continues through August with the heaviest sperm release occurring in June and July. Multiple generations of late elongated spermatids are found in association with early mitotic and meiotic cells during the months of December–August. This temporal germ cell development strategy is similar to that described in other squamates and anamniotes and is different from the spatial development exhibited by birds and mammals, in which germ cell populations collectively progress through the stages of spermatogenesis. The reptilian temporal model of germ cell development within a structurally amniotic testis leads to two hypotheses in character evolution: birds and mammals exhibit convergence of germ cell development strategy, or the spatial development strategy is a synapomorphy in amniotes, and reptiles represent an evolutionary reversal to the strategy employed by anamniotes. These findings, along with present and future data, may allow for more concrete phylogenetic analyses by creating more characters for phylogenetic matrices and may prove to be useful in future histopathological studies.

Anthropogenic habitat fragmentation and reduction are major causes of population declines and extinction. As these processes intensify, our ability to rescue imperiled taxa is critically dependent on an understanding of historical, demographic, and genetic parameters of diminishing populations. We assessed the effects of recent geographic isolation and population reduction on genetic variability for endangered Dusky Gopher Frogs, Rana sevosa. Only two populations of R. sevosa exist, each is geographically isolated and restricted to a single breeding pond, and one of them may have gone locally extinct. Therefore, we studied the largest and perhaps only population of R. sevosa. The only option for comparison to non-isolated populations was of its ecologically similar sister species (other Gopher Frogs, R. capito) and of the sister species to R. sevosa and R. capito (Crawfish Frogs, R. areolata). Variation in seven microsatellite DNA loci was assessed for each population to determine the effects of isolation and population bottleneck on R. sevosa. In comparison to the average non-isolated population, R. sevosa had significantly lower genetic variation and a strong signature of population bottleneck. In fact, R. sevosa had H_O that was 72%, H_E that was 81%, and A that was 61% of the average non-isolated population. Results indicated a severe, negative genetic consequence of recent population reduction and geographic isolation via lack of gene flow, enhanced effects of drift, and inbreeding. Extensive demographic data have been collected for R. sevosa beginning when the species was rediscovered in 1987 and continuing through our study. These previously collected demographic data aid in interpretation of our genetic data and discussion of implications for conservation and management.

The brief original description, without illustration, of Citharichthys fragilis was based on specimens collected in the central and northern Gulf of California, Mexico. We expand the description of the species, including its secondary sexual dimorphism, and compare it with C. gordae, a similar, relatively deep-water sanddab, mainly, although rarely, collected from the southern Gulf of California. We reject the recent placement of C. gordae in the synonymy of C. fragilis and conclude that both species are valid. They show an essentially allopatric distribution, C. fragilis being quasi-endemic and C. gordae endemic to Mexico. The distributional range of C. gnathus is widened from the Galapagos Islands to the Pacific coast of Colombia, and the Gulf of California is excluded from the geographical range of C. xanthostigma. A key to the species of Citharichthys from the eastern Pacific is provided.