Ophichthus brevirostris, a new species of snake eel, subfamily Ophichthinae, is described from a specimen trawled in deep water (406–440 m) off North Carolina. It is distinguished from its congeners by the following combination of characters: large orbit; filamentous pectoral fin; two preopercular pores; short snout; minute dentition; body coloration; and vertebral formula (13/60/153). It is most similar to Ophichthus arneutes from the Galápagos, O. genie from New Caledonia and Maldives, and two undescribed congeners from Seychelles and Tonga. It differs from them in its dorsal-fin origin, dentition, and vertebral numbers. Its characteristics do not agree with that of any of the 15 known leptocephali of western Atlantic relatives.

A new species of Atractus is described from Serra de Baturité, an Atlantic Forest enclave in the semiarid Caatinga of the state of Ceará, northeastern Brazil. The new species is distinguished from all congeners by the combination of 17 dorsal scale rows at midbody, long loreal, two postoculars, seven upper and lower labials, first four infralabials in contact with chinshields, seven maxillary teeth, moderate body and tail sizes, slightly bilobed and semicapitate hemipenis with lateral-tip projections, light dorsal color pattern uniformly scattered with small dark brown dots, and ventral color pattern uniformly creamish white. The new species shares most of the external morphology and hemipenis characters with A. pantostictus, differing from this taxon by general color pattern and number of subcaudal scales.

A new labrid fish, Halichoeres burekae, is described from specimens collected at Stetson Bank, Flower Garden Banks National Marine Sanctuary (FGBNMS), in the northwestern Gulf of Mexico over claystone, sponge, and coral substrata. The bright purple, blue-green, and yellow body coloration, and anterior black pigmentation of the dorsal fin in the terminal male, large black irregular spot at the base of the caudal peduncle, salmon body coloration, yellow snout in the initial stage/female, and diagnostic differences in the mitochondrial DNA cytochrome b gene separate this species from all other western Atlantic labrids. Adult H. burekae were observed in small schools along the reef crest mixed with Thalassoma bifasciatum and Chromis multilineata, and small juveniles were observed in mixed schools with juvenile Clepticus parrae. It feeds primarily on calanoid copepods and other plankton and is a close relative of H. socialis from Belize. This species is currently known from the FGBNMS and reefs off Veracruz, Mexico, in the western Gulf of Mexico.

Dissection and histological analyses revealed the swimbladder of Hemiramphus far and H. robustus to comprise a matrix of discrete, gas-filled vesicles of 1–6 mm in diameter. The vesicles are not richly vascular and no discrete capillary bed organs were found. The anterior and posterior ends of the swimbladder have asymmetric projections that extend rostrad and caudad, respectively. These projections and some surrounding fatty tissue contain what we term protovesicles, which have thick walls that we infer expand to become the thin-walled vesicles of the main vesicular swimbladder. Dissection of museum specimens of other species of Hemiramphus and Oxyporhamphus convexus confirmed the presence of a vesicular swimbladder. However, examination of museum specimens of other hemiramphids, including O. micropterus, and flyingfishes revealed only a simple sac-like swimbladder. Presence of this unusual swimbladder in two genera within the same family is indicative of a strong synapomorphy that, in conjunction with recent molecular data, suggests that Hemiramphus and Oxyporhamphus convexus are closely related.

Potamarius usumacintae, new species, is described based on specimens collected in the Río Usumacinta basin in Guatemala and México. The species is diagnosed from other freshwater ariids distributed in Mesoamerica by the following combination of features: lateral gill rakers on first gill arch 17–20 (mode 19); mesial gill rakers on first two gill arches well developed; accessory tooth patches on palate present; premaxillary tooth band length 2.4–2.9 in its width; snout length 1.4–1.8 in postorbital length; maxillary barbel not extending behind gill membrane; dorsomedian fleshy groove on head absent. A key to identify nine Atlantic slope ariid species from North and Central America is provided.

Green Anoles (Anolis carolinensis: Sauria, Polychrotidae) have been reported to alternate the sex of successive offspring, a pattern not known in any other vertebrate. However, no adaptive explanation has been posed for this novel pattern in Anolis, and the extent to which sex alternation is a phylogenetic constraint versus a facultative reproductive strategy in this taxon has not been determined. I examined consecutive offspring produced by A. carolinensis and A. sagrei from four locations in the southeastern United States over three years under a common garden design in order to identify population and species level variation in patterns of offspring sex independent of maternal and incubation environments. These data do not indicate sequential alternation of offspring sex in either species and allow for rejection of even small deviations from the pattern expected under random production of the sexes. I conclude, therefore, that anole reproduction is not universally constrained to a pattern of sequential alternation of offspring sex and speculate that this pattern is conditionally manifest depending on interactions between stress hormones and fluctuations in parental resources in the form of maternally deposited yolk steroids.

Several species of darters of the genus Etheostoma possess a chemical alarm substance, but it is not known how widespread this substance is within the genus. We performed behavioral bioassays on Fantail Darters (E. flabellare), Rainbow Darters (E. caeruleum), and Redfin Darters (E. whipplei). Redfin Darters reacted with a fright response upon exposure to skin extracts from conspecifics and Rainbow Darters. Rainbow Darters, which are known to respond to conspecific extracts, responded to skin extracts from Redfin Darters. Neither Rainbow Darters nor Redfin Darters showed a significant response to Fantail Darter extract, and Fantail Darters did not respond to skin extracts from either congeners or conspecifics. Percid alarm substance is hypothesized to originate from epidermal sacciform cells. Histological examination of epidermal tissue demonstrated that sacciform cells were present in all three species. Our results demonstrate that chemical alarm signals are not ubiquitous for the genus Etheostoma, and that the presence of sacciform cells does not always predict the presence of the alarm response.

We describe a new species of Allobates from the Magdalena Valley in Colombia. The new species and its sister species, A. talamancae, are the only two species of Allobates known to occur west of the Andes. The new species differs from A. talamancae in being smaller, possessing a diffuse pale oblique lateral stripe, and exhibiting strong swelling of finger III in adult males. Tadpoles also differ in the relative size of anterior and posterior labial papillae; in the new species anterior papillae are conspicuously larger than posterior papillae, whereas in A. talamancae they are subequal in size. Allobates talamancae and the new species are allopatric. Among the cis-Andean species of Allobates, the new species most resembles A. melanolaemus, which also possesses a diffuse pale oblique lateral stripe and a solid black throat in adult males, but from which it differs in being smaller and adult males having finger III strongly swollen and solid black pigmentation covering the chest and most of the belly.

Age and sex-based as well as individual-level diet variation are known to occur in many natural populations, and may have important ecological and evolutionary implications. In the case of individual-level diet variation, most examples come from species-poor, temperate communities, and it is currently believed that it results from population niche expansion following interspecific competitive release. We investigated and measured the intrapopulation diet variation in four species of frogs, Leptodactylus ( = Adenomera) sp., Eleutherodactylus cf. juipoca, L. fuscus, and Proceratophrys sp., that are part of species-rich frog communities of the Brazilian Cerrado. Specifically, we investigated age and sex-related, as well as individual-level, diet variation. We measured individual-level diet variation with the IS index of individual specialization, which is a measure of the degree of overlap between individual niches and the population niches. We found no ontogenetic shifts or sex-related differences in the types of prey consumed. However, we found evidence of individual-level diet variation in the four studied species (IS ˜ 0.2–0.5). There was a negative correlation between IS and the population niche width (r  =  –0.980; P < 0.0001), indicating that interindividual diet variation is more pronounced in more generalized populations. This pattern suggests that individual niche widths remain constrained even when population niche breadth is wide, consistent with the presence of functional trade-offs. We found no evidence that these trade-offs arise from morphology, since there was no diet–morphology correlation. We hypothesize that trade-offs have a behavioral or physiological basis, which needs further investigation. This is the first documented case of individual-level diet variation in a diverse tropical community, indicating that this phenomenon is not restricted to competitive release-driven niche expansion in temperate, depauperate communities.

Schilbid catfishes of the genus Eutropiichthys are reviewed. Eutropiichthys murius occurs in Bangladesh, northern India, and southern Nepal. Eutropiichthys vacha, considered by previous authors to be distributed from Pakistan across India, Nepal, Bangladesh, and Myanmar to Thailand, was found to include four species, with E. vacha limited to the rivers of eastern Pakistan, northern India, Nepal, Bhutan, and Bangladesh. Eutropiichthys burmannicus, originally proposed as a variety of E. vacha but not subsequently recognized as valid, was found to be a distinct species inhabiting drainages from the Irrawaddy River of Myanmar to the lower Salween River of Myanmar and Thailand. Two additional species of Eutropiichthys are named in this paper: Eutropiichthys britzi is described from the Irrawaddy and Sittang Rivers of Myanmar; and E. salweenensis is described from the portion of the Salween River in Thailand. A lectotype is designated for Eutropiichthys burmannicus. Hypophthalmus goongwaree, which has been considered to be a member of Eutropiichthys, was found to lack the characteristics of that genus. Similarly, Pseudeutropius murius batarensis was found not to pertain to Eutropiichthys. A key to the species of Eutropiichthys is provided.

Species of the deep-sea stomiid fish genus Malacosteus are readily diagnosed within the Malacosteinae by the presence of a single round nostril on each side of the snout, palatine bones without teeth, and a single large tear-shaped accessory light organ positioned below the anterior margin of the eye. In contrast to the many recent investigations into the biochemical basis of the red-shifted bioluminescence produced by the accessory light organ, Malacosteus has received little taxonomic scrutiny in the last 75 years. Four nominal species of Malacosteus have been described: M. niger, M. indicus, M. choristodactylus, and M. danae. Two species are considered valid: M. niger and a new species known from 182 specimens captured in temperate and sub-Antarctic waters of the southern hemisphere, the tropical Indian Ocean, and waters of the Indo-Australian Archipelago. Diagnosed primarily on the basis of postorbital photophore size and serial photophore counts, the new species differs further from its only known congener in having relatively small jaws and fleshy orbit.

We examined burrow microclimate and cocoon formation of the burrowing frog, Cyclorana australis, from northern Australia, during the dormancy season by monitoring frogs in burrows in the field. At the beginning of the dry season, while the soils were still quite moist, frogs dug shallow burrows, with 2–8 cm of soil above the top of the burrow chamber. The frogs spent 2–3 months underground without cocoons, but they began to form cocoons once the soils dried to water potentials that would dehydrate the frogs (as determined by laboratory experiments on water exchange). Frogs remained underground for up to six months, and then emerged when soil water potentials were great enough to permit water absorption, although it is unclear whether this was the primary cue for emergence. Soil temperatures adjacent to burrows were intermediate to those in full sun and full shade at 10-cm depth and increased throughout the dormancy period. Frogs removed from burrows after 2–4 months underground had a body mass 136% of their standard mass, indicating that burrowed frogs store a considerable amount of water in the bladder while in the burrows in the early weeks of aestivation. Because C. australis absorb water during the first part of aestivation (or at least maintain water they absorbed prior to burrowing), and construct a relatively impermeable cocoon during the latter part of aestivation, when they could lose water, these frogs may never experience water stress, despite being underground in the dry season for 5–6 months.

A new species of Amolops is described from a mountainous area of southern Yunnan Province, China. The species is unique in having a dark purple dorsum with small light yellow spots. The spots are smaller than the smallest finger disk. Other characters that distinguish this species from other species of Amolops include smooth skin (lacking tubercles) over the entire body and lack of dorsolateral folds, transverse bars on the legs, and a visible pineal body.

The Speckled Rattlesnake (Crotalus mitchellii) is a polytypic taxon presently composed of five subspecies that range across southwestern North America, including the Baja Peninsula and islands in the Pacific Ocean and Sea of Cortés. The principles of genealogical concordance were employed to test the taxonomic status of three of the five subspecies (C. m. mitchellii, C. m. pyrrhus, and C. m. stephensi). We used two molecular marker systems: mitochondrial (mt) DNA ATPase 8 and 6 genes (675 base pairs, bp), and introns 5 and 6 of the nuclear (n) DNA ribosomal protein (RP) gene (449 bp). These markers were evaluated across 104 individuals of C. mitchellii: C. m. mitchellii (n  =  3), C. m. pyrrhus (n  =  83), C. m. stephensi (n  =  18), with Sistrurus c. catenatus as the distant outgroup. Deep phylogenetic splits were detected in the subspecies of C. mitchellii, with 5.0–6.4% mtDNA sequence divergence (SD) separating C. m. mitchellii and C. m. pyrrhus, while C. m. mitchellii and C. m. stephensi had SD values of 6.4–7.3%. Similarly, C. m. pyrrhus and C. m. stephensi had SD values of 5.2–6.7%. In addition, C. m. mitchellii and C. m. pyrrhus were identical in all 449 intron bp, but C. m. stephensi differed from both at a single nucleotide polymorphism. Our molecular results diagnose C. m. stephensi as sister to mainland subspecies of the C. mitchellii complex, a result consistent with certain head scalation characters and its northernmost geographic distribution in this complex. Furthermore, four morphological synapomorphies (supraocular scales prominently ridged and/or creased, contact between rostral and prenasal scales, ground coloration of tail congruent with that of body, and black rings in the distal 15% of the tail) also diagnose C. m. stephensi from all other subspecies of C. mitchellii. We hypothesize that the northern distribution of C. m. stephensi likely resulted from two vicariant events: Pliocene expansion of the Sea of Cortés as the Salton Trough, and Pliocene development of the lacustrine Bouse Embayment along the Colorado River drainage. Despite earlier conclusions based on morphology, our molecular results showed no evidence of intergradation between C. m. pyrrhus and C. m. stephensi. Based on the principles of genealogical concordance, we advocate that C. m. stephensi be elevated to a full species, which renders a minimum of two species within the C. mitchellii clades we examined.

We redescribe Hypsiboas semiguttatus (Lutz, 1925) and describe its tadpole and vocalization. We also describe a new species, previously confused with H. semiguttatus from Misiones, Argentina, and potentially from Brazil. This new species differs from H. semiguttatus in being more robust, having a tadpole with complete marginal papillation (no anterior gap), and a labial tooth row formula of 3/5. We discuss the status of populations previously assigned to H. semiguttatus and discuss the relationships of the new species within the Hypsiboas pulchellus group.

We sampled the larvae of a rare streamside salamander, Eurycea junaluska, across a range of stream sizes to determine habitat use patterns at both reach (75-m length of stream) and watershed scales (i.e., the network of streams draining fourth-order watersheds and their relationship to the larger river channels). An information-theoretic approach to logistic regression indicated an association between larval E. junaluska occurrence and lower gradient (<2%) reaches with a relatively high amount of silt substrata. At the watershed scale, these types of reaches were associated with moderate-sized streams and smaller low gradient streams crossing the floodplain of larger rivers. Our results suggest that E. junaluska prefers larger stream and river channels and that past channel impoundment and modification has resulted in fragmentation of remaining populations.

The family Colocongridae and the genus Thalassenchelys are two enigmatic anguilliform taxa whose phylogenetic affinities are poorly understood. Here we present results from parsimony and Bayesian phylogenetic analyses of mitochondrial ribosomal RNA sequences from a taxonomic sample designed to test alternative placements of colocongrids and Thalassenchelys among anguilliforms. The phylogenetic analysis invariably and robustly supports a clade composed of Coloconger and Thalassenchelys, which, in turn, is supported as most closely related to the derichthyids. The degree of DNA sequence divergence observed between Coloconger and Thalassenchelys is comparable to that observed between congeners in the genus Ophichthus and lower than that observed between two members of the subfamily Muraeninae. Because no evidence has been offered to support an alternative placement of Thalassenchelys, we propose that it be included in the Colocongridae. In addition, the results of the present study are congruent with recent molecular-based hypotheses that suggest a close relationship between Anguillidae, Serrivomeridae, and Nemichthyidae, and a monophyletic group comprised of the families Congridae, Ophichthidae, Colocongridae, Derichthyidae, Muraenesocidae, and Nettastomatidae. We found no support for the three major anguilliform lineages that have been proposed based on morphology.

A large number of factors are known to affect amphibian population viability, but most authors agree that the principal causes of amphibian declines are habitat loss, alteration, and fragmentation. We provide a global assessment of land use dynamics in the context of amphibian distributions. We accomplished this by compiling global maps of amphibian species richness and recent rates of change in land cover, land use, and human population growth. The amphibian map was developed using a combination of published literature and digital databases. We used an ecoregion framework to help interpret species distributions across environmental, rather than political, boundaries. We mapped rates of land cover and use change with statistics from the World Resources Institute, refined with a global digital dataset on land cover derived from satellite data. Temporal maps of human population were developed from the World Resources Institute database and other published sources. Our resultant map of amphibian species richness illustrates that amphibians are distributed in an uneven pattern around the globe, preferring terrestrial and freshwater habitats in ecoregions that are warm and moist. Spatiotemporal patterns of human population show that, prior to the 20^th century, population growth and spread was slower, most extensive in the temperate ecoregions, and largely exclusive of major regions of high amphibian richness. Since the beginning of the 20^th century, human population growth has been exponential and has occurred largely in the subtropical and tropical ecoregions favored by amphibians. Population growth has been accompanied by broad-scale changes in land cover and land use, typically in support of agriculture. We merged information on land cover, land use, and human population growth to generate a composite map showing the rates at which humans have been changing the world. When compared with the map of amphibian species richness, we found that many of the regions of the earth supporting the richest assemblages of amphibians are currently undergoing the highest rates of landscape modification.

Many animals obtain reliable information about potential mates, including whether they are conspecific, sexually mature, and healthy or not, mostly from olfactory cues. Previous experiments with snakes and lizards have shown that individuals can recognize conspecifics, sex, mating status, and health condition of potential partners by chemical cues. Using choice experiments, we examined whether both male and female Hermann's Tortoises, Testudo hermanni, can detect and distinguish the odor of conspecifics from that of another species and an odorless control, and are able to discriminate sex and sexual maturity of individuals by chemical cues. We found that both sexes correctly discriminated between their own species and another species' odors, but only males can distinguish sex and sexual maturity of potential mates by olfactory cues. These results indicate a sexual dimorphism in olfactory sensitivity in this species that might be derived from sexual selection and suggest that males and females should rely on different communication channels during social interactions.

We used skeletochronology to determine the ages of 149 (74 females, 44 males, and 31 juveniles) Mountain Yellow-legged Frogs (Rana muscosa) from 13 locations (elevation 1509–3501 m) throughout their current range in the Sierra Nevada mountains of California. Lines of arrested growth (LAGs) from excised toe bones were distinct in these high elevation frogs, and each LAG was assumed to represent one year of age. Females ranged in age from 0–10 years (mean  =  4.1 years) and males from 0–8 years (mean  =  4.0 years). The skeletochronological age was that of the post-metamorphic frog and did not include the tadpole stage. Mountain Yellow-legged Frogs spend 3–4 years as tadpoles, but no age markers are found in their cartilaginous skeletons; thus, their total age, if both tadpole and post-metamorphic stages were included, would range up to 14 years. Females were significantly longer (snout–vent length: SVL) than males and had greater mean mass, but there was no difference in the mean ages. Juvenile frogs of unknown sex ranged in age from 0–3. The von Bertalanffy growth curve demonstrated that female SVLs were larger than males for all ages. Using a semi-parametric growth model, we also found that elevation within the Sierra Nevada range was an important variable in the relationship between SVL and age; frogs from lower elevation sites were consistently larger at a given age when compared to higher elevation sites. For each increase of 1000 m in elevation, the estimated length (on average) decreases by 8.7 mm. This is the first age determination study of a Sierra Nevada amphibian, and compared to other anuran species, Mountain Yellow-legged Frogs were found to be relatively long-lived, which will have implications for restoration and recovery plans.

Throughout the geographic range, adult Eastern Massasaugas (Sistrurus catenatus) exhibit plasticity in movement, fecundity, diet, and activity range size; however, the ecology of subadults remains unknown. We attached radio transmitters to 16 free-ranging neonate S. catenatus and monitored their movements and growth for up to 56 days prior to their initial hibernation. Neonate movement frequency (70%) was consistent with values reported for adults throughout the geographic range, but activity range size (0.36 ha) and mean daily distance moved (5.3 m) were smaller. Males gained significantly more mass than females over the first 50 days, but no difference in length was detected. Neonate S. catenatus returned to their general birthing area to overwinter. Because of ontogenetic shifts and differences in the spatial distribution of resources, regionally-specific management plans based on data for all age classes are essential in providing effective conservation measures.

Allozyme analyses were conducted on samples obtained from Trachemys scripta callirostris adults harvested in the Mompos Depression of Colombia. Genetic variability was low and there was no apparent genetic structure at either the micro- or macrogeographic scale, which contrasts markedly with the results of previous studies of a Trachemys population in the southeastern United States. These results have management implications for this subspecies and also suggest the need for further studies of the population genetics and systematics of other tropical Trachemys populations.

Brightly colored poison frogs of the family Dendrobatidae contain an alkaloid-based chemical defense against predation. The bright coloration of these frogs is generally considered an aposematic signal to potential predators; however, relatively few studies have specifically tested this hypothesis. Herein we report the results of a field-based experiment designed to test the hypothesis of aposematism in the dendrobatid frog, Oophaga ( = Dendrobates) pumilio from the La Selva Biological Station, Costa Rica. We used plasticine frog models to evaluate natural predation rates as a function of color. Predation rates on brown models were almost twice that of red models, suggesting that predators avoid brightly colored frog models. Birds accounted for the majority of attacks on the models. The results of this study provide experimental evidence in support of the hypothesis that bright coloration in dendrobatids functions as an aposematic signal to predators.

Semi-terrestrial tadpoles of the Sri Lankan dicroglossid rock frog (Nannophrys ceylonensis) feed by scraping the surface microfilm from the wet rocks on which they live. Gut content analysis of 40 tadpoles revealed microflora, microfauna, detritus, and mineral particles. Conspecific eggs and tadpoles were rarely also found in the tadpoles' guts. Absolute gut length decreased by 59% between Gosner stages 26 and 42, and the number of gut coils decreased as well. Tadpoles of N. ceylonensis shift from primarily herbivory to primarily carnivory as they develop, with the greatest shift occurring from Gosner stages 32 to 34. This dietary shift is correlated with a decrease in the length of the gut and the number of gut coils. Precocious metamorphosis of the alimentary tract to accommodate a carnivorous diet may facilitate tadpole survival and growth in a heavily shaded terrestrial environment with relatively low primary productivity.

Lizards from different families use acoustic signals in different communicative contexts. This study characterizes the hissing sounds emitted by individuals of Pristidactylus volcanensis (Polychrotidae) of both sexes, when confronted with a threatening stimulus. These hissing sounds have broadband spectra centered at 2.4–3.6 kHz throughout most of the emission. In some cases the hisses end with a downward frequency modulation component within the frequency range of the ongoing signal. The structure of these sounds resembles the alarm signals produced by other vertebrates in response to extremely stressful situations, such as an imminent predator attack. The occurrence of sound production in other Polychrotidae suggests that these displays have an ancestral origin in the family; however, the scattered occurrence of acoustic signals in lizards, points to an independent evolution of sound production in different families of these reptiles.

We comment on the results of a previous study which evaluate the accuracy of mouthpart depigmentation as an indicator of Batrachochytrium dendrobatidis (Bd) infection in anuran larvae. Macroscopic mouthpart inspection is a useful technique for Bd identification since it is practical and nonlethal; however, this method is also expected to result in increased rates of false negatives and false positives when compared to other methods. We therefore suggest that there are scenarios in which the use of mouthpart depigmentation is not appropriate, and we present a conceptual framework for deciding when mouthpart depigmentation is an appropriate indicator of oral chytridiomycosis in tadpoles. We conclude that more sensitive techniques are preferable when false positives or false negatives could result in the incorrect classification of populations as infected or uninfected, namely when Bd is absent or present at low prevalence. In contrast, mouthpart depigmentation is an appropriate indicator of infection when Bd prevalence is high and especially when conservation or practical concerns preclude lethal methods such as histological preparation.