Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact helpdesk@bioone.org with any questions.
We describe a new forest skink species of the genus Sphenomorphus based on specimens from northern Vietnam and from Hainan Island, southern China. The new species is differentiated from the congeners by the combination of the following characters: size small (SVL 35.8–48.8 mm); prefrontals in contact with each other mesially; supralabials seven; primary temporals two; external ear opening present, without lobules, tympanum slightly sunk; midbody scales in 32–34 rows; dorsal scales smooth, paravertebral scales 65–72, not widened; limbs well developed, pentadactyl; 15–19 smooth lamellae under fourth toe; free margins of upper and lower eyelids edged in white; neck, dorsum, and tail base bronze-brown with a discontinuous dark vertebral stripe; upper lateral zone black, interrupted by small light spots from behind the neck. In addition, we provide a review of Vietnamese Sphenomorphus with the first country record of Sphenomorphus mimicus. The generic allocation of Sphenomorphus devorator (allocated to Scincella), Leptoseps tetradactylus (allocated to Sphenomorphus), and Livorimica bacboensis (allocated to Sphenomorphus) is discussed.
We describe a new species of semiarboreal frog in the genus Gephyromantis from midelevation rain forests of the Marojejy Massif in northeastern Madagascar, which, according to previously published molecular data, forms a clade with Gephyromantis ambohitra, Gephyromantis asper, and Gephyromantis spinifer. The new species is morphologically most similar to G. ambohitra but differs by its advertisement call and a high genetic distance in mitochondrial DNA. Considering intensive recent logging activity in Marojejy National Park, we propose an IUCN status of Vulnerable for this new species.
We describe a new species of marsupial frog (genus Gastrotheca) from an isolated patch of cloud forest in the upper reaches of the Pachachaca River, a tributary of the Apurímac River in southern Peru (Apurímac Region). The new species is small with males less than 30 mm and a single female 35.3 mm in snout–vent length. A juvenile was collected from inside an epiphytic bromeliad at ∼3 m, suggesting that this species is arboreal or uses bromeliad tanks as microhabitats. We describe the advertisement call, which has a dominant frequency above 2.2 kHz. Based on morphology and advertisement call, the new species is most similar to Gastrotheca piperata described from the Yungas of Bolivia. The new species differs from G. piperata by having smaller size, no dermal fold on the tarsus, a bluntly rounded to vertical snout in profile, gray coloration on dorsal surfaces of Fingers I and II and by producing advertisement calls that have a higher dominant frequency and a smaller number of pulses.
Mel José Rivera Rodríguez, Ehren J. Bentz, Daniel P. Scantlebury, Rebecca R. John, Daniel P. Quinn, John S. Parmerlee, Robert W. Henderson, Robert Powell
Typhlops tasymicris was known previously from only two specimens, both immature females collected on Grenada in 1968. In June 2010, we rediscovered the species on Union Island, St. Vincent and the Grenadines, where we encountered five individuals (and captured four) on the forested slopes above Chatham Bay. The new specimens agree closely with the two previously reported individuals for all scale characters and coloration, but they differ in sizes and proportions. At least two of the new specimens are adults, but all seem to be females. This first record of a typhlopid snake in the Grenadines suggests a greater range than indicated by the earlier specimens. Although suitable habitat occurs nowhere else on Union Island, the species could occur elsewhere in the Grenadines where relatively mature forests persist. DNA sequence data clearly show a closer affinity with South American species than with any West Indian congeners.
During courtship, adult male plethodontid salamanders transfer protein pheromones that augment female receptivity. The majority of plethodontid species apply pheromones transdermally (to the female's dorsal skin). These pheromones apparently diffuse through the skin and enter into circulation, a unique type of pheromone delivery in vertebrates. In contrast, a behavioral and physiological transition occurred in the Plethodontinae, resulting in one clade of species (Plethodon glutinosus group) that uses a different pheromone delivery mode. Males within this clade apply pheromones directly to the nares of a female, and the pheromones subsequently are detected by the vomeronasal organ. We tested whether female Red-Legged Salamanders (Plethodon shermani), despite normally detecting pheromones via the vomeronasal organ, have retained the ancestral ability to respond to pheromones delivered transdermally. We staged courtship encounters and recorded the behavior of females given either pheromones or control solutions on the dorsal skin. Female receptivity (as inferred from courtship duration) in P. shermani was not affected by dermal application. Also, we used immunocytochemistry on female vomeronasal neurons to show that (1) females responded normally to pheromones delivered to the nares and (2) dermal application of pheromones did not activate vomeronasal neurons. We conclude that female P. shermani are not stimulated by pheromones delivered dermally and infer that this condition may characterize all the members of the P. glutinosus group, which use olfactory pheromone delivery.
In applying foraging theory to cryptic predators like many snakes, one of the most difficult variables to measure is effort spent in foraging. We estimated foraging effort from time invested in foraging using records for habitat use accumulated over a period of three years for 50 radio-tracked adult watersnakes (Nerodia sipedon). Because watersnakes eat predominantly aquatic prey, and limited prey records for the population studied were all fish, time spent foraging was estimated from the number of records in which snakes were found in water compared to the total number of records. Based on the data collected, this population of watersnakes devoted 1.43–2.38% of its time to foraging. Although the data do not permit allocation of foraging effort for most snakes to specific times, combining all relocation data suggests that adult watersnakes in this population forage infrequently. Opportunistic records of stomach contents regurgitated by captured snakes of all sizes suggest that these watersnakes find fish prey by active foraging and that the adult population benefits from periodic exploitation of dead or dying large fish (trout) following stocking.
Vocalizations are critical advertisement signals used during anuran courtship. In most species, acoustic signals have primacy, but visual cues also have been shown to play an important role in anuran mate attraction. Male Túngara Frogs, Physalaemus pustulosus, produce advertisement calls, and males that are successful in attracting a mate build conspicuous white foam nests in which fertilized eggs are deposited. Foam nests persist for several days and on subsequent nights, male frogs are often observed calling adjacent to these foam nests. We tested the hypothesis that females approach the vocalization of a male adjacent to a foam nest preferentially. We conducted choice tests allowing females to choose between two speakers broadcasting a male vocalization—one speaker adjacent to a foam nest and the other speaker lacking a foam nest. Females expressed a significant preference for a speaker with a foam nest when the nest was visible. These results indicate that males may increase their probability of attracting a mate when calling adjacent to a foam nest relative to males located farther from a foam nest.
Over the past three decades the Booroolong Frog (Litoria booroolongensis) has declined across the majority of its range, with predation from introduced fish hypothesized as contributing to this decline. In this study we undertook an experiment in artificial enclosures to test the propensity for three introduced fish species (European Carp, Cyprinus carpio; Redfin Perch, Perca fluviatilis; and Mosquito Fish, Gambusia holbrooki) to prey on L. booroolongensis tadpoles. We manipulated the presence–absence of refuge habitat and alternative prey to examine how these two factors may affect tadpole predation risk. All three fish species consumed L. booroolongensis tadpoles, with juvenile C. carpio consuming nearly all tadpoles in all treatments. The provision of rocks within enclosures did not reduce the proportion of tadpoles consumed for any of the fish species examined; however, there was a reduction in the proportion of tadpoles consumed by P. fluviatilis and G. holbrooki when alternative prey were present. Although L. booroolongensis currently persists in streams inhabited by these introduced fish, this study supports the likelihood that these species are having a negative impact on populations of this endangered frog.
Chemical contamination and physical alteration of the environment can separately or in combination cause changes in the abundance and diversity of amphibian species. However, these factors are typically considered in isolation using experiments focused on single life stages. We examined the terrestrial performance (i.e., growth, survival) of Southern Leopard Frog (Rana sphenocephala) juveniles that had been chronically exposed to one of three initial concentrations of the heavy metal cadmium (0, 5, or 18 µg Cd/L) as aquatic larvae. Juveniles were reared in terrestrial enclosures within deciduous forest and open field habitats through their first growth season (summer to autumn). The effect of cadmium (Cd) on terrestrial survival depended on habitat type; survival increased with Cd concentration in the field enclosures and decreased with Cd concentration in the forest enclosures. Terrestrial survival was 73% in the forest enclosures and 54% in the field enclosures, but the difference was not significant. The trend for mass at metamorphosis to increase with Cd concentration was maintained through the first growth season, and frogs collected in autumn from the field enclosures were heavier than their counterparts in the forest. Individuals that survive larval Cd exposure may benefit from a large size, but carryover effects that reduce juvenile survival may occur in forest habitats. The conversion of forest habitat into open fields may be of mixed consequence to the Southern Leopard Frog, in the form of lower survival but better growth among the survivors.
Studies that assess current and historical population densities accurately provide valuable information for management of wildlife species, particularly those in need of immediate conservation concern. The Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis) has experienced drastic declines throughout its range during the previous few decades. This study documents its continued decline over the past 25 years in the last known remaining population in southern Indiana. We conducted mark–recapture surveys from June 2008 to October 2008 and July 2009 to September 2009 at 35 sites. Despite a considerable increase in effort over previous surveys, we documented fewer total captures and extremely low population densities. Density was estimated at 0.06 individuals/100 m2, and catch per unit effort was 0.05 individuals/person hour throughout the entire study area. This represents not only a significant decline in numbers from the historical study, but also is well below that reported for populations throughout the species' range. Sex ratios were skewed significantly toward males (2.6 males ∶ 1 female). No subadults or larvae were found, and only two nests were located. This population consists almost exclusively of large, older-age class individuals that show limited signs of reproduction.
We describe a new species of Luperosaurus from the Luzon faunal region, northern Philippines. The new species is most similar to, and has long been confused with, Luperosaurus cumingii from Luzon Island but differs from this and all other Luperosaurus by numerous characters of scalation, color pattern, and a suite of variables related to its small body size. The new species has been recorded at four localities along the eastern seaboard of Luzon and on Camiguin Norte, a small island just northeast of Luzon; it may also occur on Polillo and Lubang Islands. Data from our recent survey work suggest that some Luperosaurus species may be adapted to low elevation, coastal forest and that these species may now be encountered rarely now because this habitat type is so severely imperiled by centuries of deforestation and near complete development of virtually all Philippine coastlines.
In this paper we describe a new species of toad of the genus Incilius. This species was originally recorded as Bufo simus, a synonym of I. occidentalis. It differs from I. occidentalis by having the following combination of characters: a pale brown dorsal ground color with numerous dark brown spots and lacking a vertebral stripe and a high density of granules on the dorsum producing a rugose skin texture. The most developed of the cranial crests is the supraorbital, while the parietal is poorly developed. Incilius mccoyi inhabits pine and pine-oak forests of the southwestern Sierra Madre Occidental in Chihuahua, Mexico.
Two morphologically distinctive, monotypic genera of Australian agamid lizards, Moloch and Chelosania, are of uncertain relationship to the main Australian arid zone radiation, the amphiboluroids. We report that the karyotypes of both Moloch horridus and Chelosania brunnea are both 2n = 36 with six pairs of macrochromosomes and 12 pairs of microchromosomes. This is probably the plesiomorphic karyotype for agamids, and different to the 2n = 32 karyotype (10 pairs of microchromosomes) that is a synapomorphy of the amphiboluroids. This finding supports recent DNA sequencing studies of Australian agamids that find an early origin and independent branching position for these two genera. Both genera therefore seem to have no special relationship with the amphiboluroids, indicating colonization of the arid habitats by more than one lineage of agamids at an early stage of their diversification on the Australian continent.
Exposure to altered conductivity can negatively impact many freshwater system inhabitants, including bacteria, plants, invertebrates, and vertebrates. Several studies have shown increased conductivity to affect amphibian behavior and ecology. Comparatively fewer studies have taken a physiological approach to understanding the effects of altered conductivity in amphibians. This study used laboratory experiments to assess conductivity effects on stress hormone (corticosterone) levels in Jefferson Salamander (Ambystoma jeffersonianum), Wood Frog (Rana sylvatica), and Gray Treefrog (Hyla versicolor) larvae. Prey consumption (only in A. jeffersonianum) and survival (in all species) also was examined after exposure to increased conductivity (0, 2,000, 4,000, and 8,000 ppb). There was a significant positive effect of increased conductivity exposure on baseline corticosterone levels in A. jeffersonianum after 1-week exposure. Exposure to increased conductivity did not influence baseline corticosterone levels in R. sylvatica and H. versicolor or confinement-induced corticosterone levels in all three species. Prey consumption in A. jeffersonianum was significantly negatively associated with increased conductivity (4,000 and 8,000 ppb). No mortality occurred in any species as a result of exposure to increased conductivity. These results suggest that exposure to increased conductivity can be a powerful environmental stressor for amphibians, despite having species-specific effects on corticosterone levels.
We examined how differences in the allocation of resources influence prebreeding somatic stored energy reserves (fat and glycogen) in males and females of the hylid frogs Pseudacris crucifer and Pseudacris triseriata. Males had shorter snout–vent lengths than did females but similar wet and dry carcass masses. Nonpolar lipid and glycogen contents of the carcass increased with carcass mass in males but not in females. Similarly, triglyceride and glycogen contents of the liver increased more acutely with increasing liver mass in males than in females. Ovarian mass in gravid females correlated with body size and in P. crucifer the gonadal-somatic index increased with increasing body size, indicating a greater than proportional increase in ovary mass with increasing body size. These findings suggest that, during the pre-reproductive period, larger males allocate more energy toward preparation for courtship activity than do smaller males, whereas larger females may allocate more energy toward production of eggs.
The first snake craniomandibular fossil specimen from the Campanian–Maastrichtian of South America is described herein. The specimen, from the Allen Formation in Río Negro Province, consists of an incomplete anterior portion of a left dentary. The general morphology of the bone resembles that of the basal legged snake Najash Apesteguía and Zaher and the small madtsoiids from the Eocene–Miocene of Australia. The dentary was found associated with several isolated snake vertebrae, most of which are referable to madtsoiids, thus it probably belongs to one of the already known madtsoiid taxa.
The oldest paleontological record of the Stinkpot Musk Turtle, Sternotherus odoratus, from the WaKeeney local fauna (approximately 10 million years ago, Mya) is refuted here. Kinosternids from this fauna are represented only by the genus Kinosternon. Kinosternon sp. probably represents a new taxon, but lack of sufficient material hinders a proper description. A gap of between 9 and 12.5 million years now exists between the first occurrences of Sternotherus (at approximately 4.5–7 Mya) and sister group Kinosternon (between 16 and 17 Mya).
Turtles are the most common vertebrates in the upper Eocene and lower Oligocene rocks of Nebraska. In this work we characterize a striking decline in overall turtle abundance in the early Oligocene at two Nebraska localities: Toadstool Park and Scotts Bluff National Monument. In both locations, this decline occurs at a prominent change in rock composition, the contact between the Orella and Whitney members of the Brule Formation. The two study sites are 140 km apart, suggesting that this decline in turtle fossils was a regional event. Although the reasons for the abundance changes are not entirely clear, we present preservation biases or regional cooling and drying as competing hypotheses.
Although the treefrog Hypsiboas albopunctatus (Spix, 1824) (Anura: Hylidae) is abundant in South America, especially in regions of open vegetation in Brazil, information regarding its natural history is still scarce. This study describes its ecology including aspects of microhabitat use, population dynamics, diet, and reproduction in the Cerrado biome of central Brazil. We used model selection to test hypotheses of variation in survival and recapture rates as a function of differences in sex, seasonality, and climatic variables. We also tested hypotheses regarding sexual dimorphism. This species uses mainly herbaceous vegetation and bushes along margins of the ponds. Apparent survival, estimated using the Cormack-Jolly-Seber mark-recapture model, was higher for males than females and was negatively correlated with rainfall. Recapture probability was influenced by seasonality, presenting higher values in the wet season. This highlights the influence of weather, especially seasonal rainfall, on the population dynamics of anurans occurring in tropical savannas. The analysis of previously preserved individuals showed strong sexual dimorphism in body size and shape, with females being larger than males. Female body size positively correlated with clutch volume. Hypsiboas albopunctatus seems to have a generalist diet, consuming primarily Coleoptera, Aranae, and Orthoptera (assuming accidental vegetal ingestion). Prey size was positively correlated with anuran head size. Hypsiboas albopunctatus seems to be a generalist, as demonstrated by its continuous activity and reproduction, generalist diet, and habitat use, presenting some breeding adaptations to enhance offspring size, such as sexual size dimorphism related to clutch volume in females.
Brachycephalus didactylus, a leaf litter frog endemic to the Brazilian Atlantic rain forest, is considered the world's smallest tetrapod. Currently, there is little information about the ecology of this species. In this study, we estimated the population density and analyzed the diet, sexual dimorphism, and some reproductive aspects of two populations of B. didactylus in Rio de Janeiro State, Brazil. The estimated density was 4.0 and 1.2 ind/100m2, suggesting that this is not a locally rare species. However, collecting these frogs may be difficult because of their very small body size (< 11.0 mm SVL) and cryptic color pattern. Individuals from the two populations did not differ in body size, but females from one population were significantly larger than were males. In both populations, the most important food items consumed were Acari and Collembola, most of them measuring less than 1.0 mm in length. Females of the two populations had 3.6 ± 1.3 and 2.5 ± 0.8 mature oocytes averaging 1.6 ± 0.5 mm and 1.4 ± 0.5 mm in diameter, respectively. Frogs with direct-development generally deposit a relatively small number of eggs, and this trend is even more extreme in miniaturized species, such as B. didactylus, which probably lays one egg per clutch. Because the body size of females significantly influenced the mean diameter of oocytes, but not the number of oocytes per female, reproductive success is probably associated with the production of relatively large eggs and, consequently, larger froglets, which may confer an adaptive advantage.
Sampling methods that can be implemented efficiently while minimizing bias are central for achieving strong statistical power in field studies. We estimated site occupancy and detection probabilities for Red-Backed Salamanders, Plethodon cinereus, using natural cover object (NCO) and leaf litter surveys and tested the power of these methods to detect occupancy differences in simulated data. Both NCO and leaf litter surveys performed well in their ability to detect P. cinereus (pˆ = 0.59 ± 0.07 [± 1 SE]; 0.49 ± 0.08, respectively) and produced similar site occupancy estimates (ψ ˆ = 0.75 ± 0.09; 0.77 ± 0.11, respectively); however, leaf litter searches took three times longer to complete. Our simulation study revealed the time required to complete leaf litter surveys limited the number of sampling sites, which reduced statistical power for detecting a 25% change in salamander occupancy between two groups of sites. Natural cover object searches provided greater power for detecting a similar change in occupancy, largely because of high sampling size. Although reliable salamander detection data can be collected quickly using NCO surveys, we discuss situations where this technique may not be appropriate. Our study highlights the importance of accounting for imperfect detection probability when conducting visual encounter surveys for terrestrial plethodontids.
Understanding the causes of population declines is difficult when the ecology of the organisms themselves is insufficiently known. The common South American toad, Rhinella arenarum, inhabits a wide variety of habitats. Their populations are abundant; however, life-history characteristics of the adult, including reproductive traits, are poorly known. We studied the reproductive ecology of R. arenarum for several populations in central Argentina during two breeding seasons (2007–08). Breeding activity was compared for the two seasons with respect to variation in habitat variables. Females deposited a mean of 23,226.67 eggs per clutch (N = 10), and snout–vent length did not show any significant effect on the number of eggs. Spawning females lost 27% of their mass when spawning occurred, and the heavier females had greater reproductive output. We found a significantly positive relationship between amplexed male and female snout–vent lengths, indicating size-assortative mating. Females in good body and somatic condition produced larger clutches independent of snout–vent length. Because clutch hydration in ponds occurs, reproductive effort as a function of body loss mass of spawning females is a more appropriate estimate of reproductive output for R. arenarum. Trends in the number of egg strings over several breeding periods can provide information about changes in population size. Long-term studies designed to monitor populations are needed to determine the impacts and consequences of environmental changes.
This article is only available to subscribers. It is not available for individual sale.
Access to the requested content is limited to institutions that have
purchased or subscribe to this BioOne eBook Collection. You are receiving
this notice because your organization may not have this eBook access.*
*Shibboleth/Open Athens users-please
sign in
to access your institution's subscriptions.
Additional information about institution subscriptions can be foundhere