Bolitoglossa nicefori is a terrestrial salamander only known from its original description. We report the discovery of two populations of this species; analyze annual reproductive activity, diet, and microhabitat use of one population; and compare this information with that known for other species of Bolitoglossa. Sexually mature males ranged between 29 and 50 mm standard length and females between 39 and 75 mm. Histological analyses of testes and ducts revealed the presence of sperm through the year, indicating continuous reproductive activity for males. Adult females were captured year-round; however, reproductive females were observed only during the driest months of the year (November to February), indicating that females have a seasonal reproductive activity. The contents of 89 stomachs were analyzed, and perch height, type of vegetation, and substrate type were registered. The diet of this population consists of 13 items, with ants and coleopterans accounting for 87% of food ingested by the different age and sex classes. Ants represent 58% of the diet, reflecting their greater availability in this microhabitat. Intra- and intersexual differences in diet were not found. Bolitoglossa nicefori exhibited both terrestrial and arboreal behaviors related to temperature and humidity conditions during the daily cycle. Mature nonreproductive females, males, and juveniles were found perching from 0–60 cm above the ground on Araceae bushes that predominate in the study area, whereas reproductive females were always found within the leaf litter. Life-history features of B. nicefori are determined by environmental conditions; however, they follow common trends shared with other species of Bolitoglossa.

I describe a new species of Anolis formerly referred to as Anolis (or Norops) altae from Monteverde, Costa Rica. The new species differs from Anolis altae by having a small unilobate hemipenis (large and bilobate in A. altae), in male dewlap coloration (male dewlap more or less uniformly reddish-orange in A. altae versus basal portion yellow ocher to orange yellow, distal portion reddish-orange in the new species), and in the mean values of several scalation and morphometric characteristics (e.g., ratio tail length/SVL 1.8–2.2, mean 2.1 in A. altae vs. 1.7–1.9, mean 1.8 in the new species). At this point no characteristics, besides geographic location, are known to separate females of the new species from A. altae.

A new species of keel-headed amphisbaenian of the genus Anops is described from the Cerrado of the Jalapão region, Tocantins state, Brazil. This new species of Anops is described from a single specimen, which may be easily distinguished from the other species of the genus, Anops bilabialatus and Anops kingii, by showing an extremely narrow head (37.2% head length); a row of eight occipitals anterior to the first body annulus; temporal present; mental and postmental fused; four postgenial rows located between the malars; and two malars posterior to the second infralabial. The new species is the first of the genus found in the Cerrado core area, and, based on the available records, the single species in the genus may be restricted to this region.

All animals studied to date exhibit sleep or sleeplike behavior, but sleeping animals are at risk because they are generally unaware of and unresponsive to the environment. Selection should favor animals that make good trade-offs between sleep attributes (e.g., location, timing, duration) and predation risk; in other words, sleep should be facultative. The few studies that document sleep plasticity in response to predation risk have focused on endothermic vertebrates. We tested the hypothesis that a representative ectothermic vertebrate, the Desert Iguana (Dipsosaurus dorsalis), exhibits behavioral sleep plasticity in response to predation risk. We found a reduction (>50%) in total sleep time during daylight when Desert Iguanas were exposed continuously to a Sidewinder (Crotalus cerastes) in a laboratory setting. During asynchronous eye closure (ASEC) bouts, the eye of the iguana distant to the Sidewinder was more often closed, whereas the proximal eye was more often open, suggesting unihemispheric sleep (which has not been confirmed yet in reptiles) to maintain vigilance. Desert Iguanas spent more time aboveground and less time within their burrows when the Sidewinder was present. Snake activity was minimal, with movements occurring just 1.1% of the time, suggesting that iguanas were not merely responding to a moving object. Our findings suggest that Desert Iguanas will forgo sleep and remain vigilant when the potential for predation is increased. These findings illustrate the importance of ecology in shaping the behavior and probably the associated physiological and neurological attributes of sleep in ectothermic vertebrates.

Wild Desert Tortoises, Gopherus agassizii, are eating different foods now than they were decades ago, because exotic plant species have invaded and flourished in the Mojave Desert over the last century. Reservations about the nutritional quality of exotic vegetation compared to native vegetation led us to conduct feeding experiments with growing, juvenile Desert Tortoises. We determined the digestibility of dry matter, energy, fiber, and nitrogen in four foods: Achnatherum hymenoides (a native grass), Schismus barbatus (an exotic grass), Malacothrix glabrata (a native forb), and Erodium cicutarium (an exotic forb). The largest nutritional differences among diets were between food types (fresh forbs and dry grasses) rather than between native and exotic species. The two grass diets were higher in fiber content and they contained less digestible energy than the two forb diets. The grasses contained little protein, and tortoises actually lost mass and body nitrogen while eating them. The exotic forb yielded more energy and nitrogen per unit dry mass than did the native forb, but this may be related to differences in phenological stages and associated fiber contents of these foods when they were collected. Juvenile tortoises gained weight rapidly when eating forbs and showed no evidence of having a lower digestive capability than did adults, despite their small size and immaturity. Estimates of nitrogen requirements compared to annual nitrogen intake on these diets suggested that growth of juveniles may be limited in part by dietary nitrogen.

Although the number of temporary wetlands used by many amphibian species has declined nationally, permanent wetlands have increased on the landscape in many regions. Species like Bullfrogs (Rana catesbeiana) may benefit from permanent wetlands and increase their density on the landscape, making them more likely to encounter wetlands used by amphibians breeding in temporary ponds. Although Bullfrogs are typically viewed as inhabitants of permanent wetlands because of their long larval periods, they are known to use temporary ponds. This study examined how larval density influenced proportion of Bullfrogs metamorphosing, time to metamorphosis, mass at metamorphosis, and total Bullfrog survival in mesocosm ponds. Proportion of Bullfrogs metamorphosing and tadpole development were greatest in mesocosms with low tadpole density with up to 25% of tadpoles reaching metamorphosis. Our study indicates Bullfrogs can metamorphose in more northern climates within a single season across a range of densities, and highlights the potential for Bullfrogs to successfully use temporary pond environments.

An animal's requirements (e.g., food vs. shelter) from its environment are likely to vary seasonally and, therefore, so too should habitat selection. Here, we test the hypothesis that Texas Ratsnakes (Elaphe obsoleta) choose habitats based on prey availability during their active season and on cover during winter. We examined snake habitat selection at three spatial scales and compared that to abundance of small mammals and nesting birds, which we confirmed by diet analysis to be the snakes' principal prey. Small mammal trapping and avian point counts showed that overall prey abundance was higher on mesas and slopes compared to savannahs. Compared to availability of habitats within the entire study area, snakes selected home ranges with a high proportion of slope habitat. Within home ranges, however, selection for slopes was exhibited only during winter when foraging is at a minimum and snakes are relatively inactive. Snakes did not use habitat within home ranges selectively during the active season or during the avian breeding season. The latter result suggests that ratsnakes are effective avian nest predators despite preying on birds opportunistically. However, it is also possible that some individual ratsnakes specialize on birds, whereas the majority preys on mammals. Microhabitat analysis comparing winter and active season sites showed that snakes preferentially used areas of high canopy cover and rock ground cover during winter. Collectively these results provide limited support for the hypothesis that ratsnakes use habitats based on prey availability but do indicate that ratsnakes select winter habitat based on cover availability.

The North American genus Thamnophis is a widely distributed and abundant group of snakes. Previous research has indicated that most garter snakes are generalist predators that largely consume anurans, with some degree of geographic and temporal plasticity in response to resource variation. We studied the dietary habits of the Plains Garter Snake, Thamnophis radix, based on stomach contents from 548 animals collected in the field from 1995–2006 at the northern limit of the species' range in central Alberta, Canada. Feeding frequency overall was low (22%) and was highest in spring and early summer. Diet was composed mainly of anurans (85%), especially Wood Frogs (Rana sylvatica) and Boreal Chorus Frogs (Pseudacris maculata), and occasionally invertebrates (10%) and small mammals (5%). Small snakes (<200 mm) began feeding shortly after birth and consumed mainly smaller frogs. Larger snakes ate a wider range of prey sizes and types, but frogs still constituted the majority of prey consumed. Despite sexual size dimorphism, males and females ate prey of the same size and type; however, gravid females contained food less frequently than both males and nongravid females. This study adds to the growing number of dietary studies on T. radix and provides additional evidence for the ecological plasticity of Thamnophis species. Further studies are needed to examine how important these snakes are as components of wetland food chains.

Multiple paternity is widespread among reptiles in general and turtles specifically. However, its frequency is highly variable even among closely related species. Paternity is an important component of the genetic mating system of a species, and it can provide insight into the social mating system of the species. I investigated the occurrence and frequency of multiple paternity in a population of Blanding's Turtle (Emys blandingii), a rare freshwater species. A high frequency of multiple paternity was detected in this population, with 13 of 16 (81%) clutches showing evidence of siring by multiple males at one locus and nine of 16 (56%) at two or more loci. Multiply sired clutches received approximately equal contributions by both, and rarely three, sires. Therefore, polyandry appears to be the most common reproductive strategy for females in this population. Evidence was also found to suggest that sperm storage between years may occur in this species. The high frequency of multiple paternity observed here suggests that multiple mating may be beneficial to females and/or their offspring. Further research is needed to determine whether this is the case and, if so, how females may benefit from multiple matings.

Rhinella spinulosa is a toad common in rivers, streams, and steppe wetlands where they face a variety of insect predators. Rhinella spinulosa tadpoles are known to be unpalatable to dragonfly naiads at some developmental stages. In this paper, we studied susceptibility of R. spinulosa tadpoles to predation by two species of predators, water bugs (Belostoma bifoveolatum, Belostomidae) with piercing-sucking mouth parts and dragonfly larvae (Rhionaeschna variegata, Aeshnidae) with chewing mouth parts. We conducted feeding trials to test the effectiveness of tadpole chemical defenses against water bugs. We also performed behavioral and choice experiments to study whether tadpole behavior influences their vulnerability to predators, and whether R. variegata has the capacity of discern between palatable (stages 38–45) and unpalatable tadpoles (stages 24–26). Rhinella spinulosa tadpoles, when fully palatable, responded by reducing their activity levels in the presence of dragonfly larvae but did not alter their behavior at unpalatable-early stages. Chemical defenses were not effective against the sucking predator (B. bifoveolatum) and no changes in tadpole activity were observed. Selectivity experiments revealed the ability of dragonfly larvae to distinguish between unpalatable and palatable tadpoles. Inducible (behavior) and constitutive (toxins) defenses observed in R. spinulosa tadpoles and the transition between them could result in an important survival mechanism in response to variable predator risk in the habitats in which they co-occur.

Secondary sexual characteristics are often under intense sexual selection as ornaments for attracting mates or as traits associated with male-male competition such as combat. Secondary sexual traits under sexual selection are predicted to be related to male phenotype, because only high-quality males should be capable of developing these costly and exaggerated traits. Therefore, high-quality males should have larger or more elaborate secondary sexual traits than poor-quality males. We used the Green Frog (Rana clamitans) to test this hypothesis using three sexually dimorphic traits (the enlarged forelimbs, enlarged tympanum, and yellow throat of the male Green Frog) and two measures of male phenotype (body condition and size). Forelimb size was condition-dependent—males with larger forelimbs were in better condition than males with small forelimbs. Males with an intermediate shade of yellow on their throat tended to be in better condition than males with dark and light yellow throats, but the degree of yellow was related to body size—males with a dark yellow throat were larger than males with a light yellow throat. There was no evidence of condition-dependence of tympanum diameter; although after correcting for body size, males with a large tympanum had large forelimbs suggesting that tympanum size reflected some other, unmeasured, indicator of male quality. These results are consistent with the hypothesis that males produce multiple signals and cues that reflect different aspects of male quality. Females can maximize the benefits of mate choice by using multiple traits to assess male quality.

Lizards of the viviparous genus Phymaturus inhabit regions in which a significant proportion of the year is unsuitable for growth and reproduction. All Phymaturus studied have shown biennial female reproductive cycles. We studied the reproductive biology of Phymaturus zapalensis, which lives on rocky outcrops in cold and arid environments of Patagonia, Argentina. Male and female reproductive cycles, mean annual reproductive output, and sexual dimorphism were analyzed. Additionally, new dimorphic traits of Phymaturus antofagastensis and Phymaturus tenebrosus were compared with published data. The female reproductive cycle of P. zapalensis is annual-biennial (because of skipping a year of reproduction), and synchronous with the annual male reproductive cycle. In midspring, males show spermatozoa in epididymis, and females have enlarged follicles, characteristic of imminent ovulation. The presence of 45% of the adult females with oocytes smaller than 4 mm, in all months of capture except October, suggests a year of skipped reproduction. Female P. zapalensis had greater SVL and a relative larger interlimb length than males. Males exhibited relatively greater head width, neck width, and diameter of front and hind legs. Our data indicate that the potential for annual reproduction exists in this biennial breeding genus. The capability of P. zapalensis to perform either an annual or biennial reproductive cycle, instead of the characteristic biennial cycle of the genus, could be the result of a longer activity season, higher temperatures during spring, summer, and autumn months, together with a high-energy omnivorous diet.

We studied the population biology of the Spiny-Tailed Iguana (Ctenosaura bakeri) endemic to the Honduran island of Utila and previously assumed to be close to extinction. Here, for the first time, we present a comprehensive mapping of its overall distribution and nesting area. The total range of C. bakeri comprised about 1,091 ha of mangrove swamp. Nesting sites were restricted to 109 ha of sandy coastal territory. We used two closed capture-recapture models to estimate adult population densities at 35–78 and 72–114 adults/ha within three mangrove areas, respectively. Population densities were largely related to the presence of suitable retreats. Population estimates for the entire mangrove habitat based on these mean adult densities ranged from 57,823–93,826 individuals, far higher than earlier reports have suggested. Also, no evidence was found for an unbalanced demographic structure. About 27% of all iguanas captured were juveniles (<150 mm snout–vent length). Notably, juveniles were difficult to detect and capture, and additional sightings of 0.8–2.3 juveniles/day indicated even higher abundances than given by captures. The sex ratio of males to females (1 ∶ 1.2) was consistent with reports of adult social groups in other large iguanids. Threats to C. bakeri included hunting and habitat pollution but mainly the loss of habitat and nesting sites caused by unrestricted property development. Without proper habitat management, we anticipate significant declines of the C. bakeri population within the next 20 yr.

The effects of sex, ontogeny, and season on the diet of Ranitomeya virolinensis were studied over one year. The diet of this Andean species is composed mainly of small prey; the most important prey categories according to index of relative importance (IRI) were Acari, Formicidae, Holometabolous larvae, and Collembola. There were no differences in total prey gut content over time assessed in number and volume; however, the diet composition of this Santander Poison Frog changed between dry and wet seasons, with Formicidae, holometabolous larvae and Collembola as the prey categories that contributed most to the difference. Males had fewer prey in their guts than females, but there were no compositional differences between sexes. There was a shift in the importance of prey caused by ontogeny. Mean prey volume increased with body size, whereas the occurrence of Acari and Formicidae varied inversely with SVL. Formicidae was the second most important prey category according to IRI. Therefore it is an important category as has been described previously for other Dendrobatid species. However, its importance fluctuated with the season. Acari was the most significant prey type in R. virolinensis as is the case for other small related species of the genus, although its importance changed with the ontogeny. The diet of this frog had a substantial phylogenetic component because closely related species have similar diets; nevertheless, its diet is clearly affected by other intrinsic and extrinsic factors.

In lizards, chemical senses play important roles in ecology and behavior. Previous studies have shown that food chemical discrimination, phylogeny, and foraging modes are associated in squamates. The two major clades, Iguania and Scleroglossa, display marked differences in foraging behavior. A large majority of iguanians are primarily ambush foragers and lack prey chemical discrimination, whereas scleroglossans, mainly active foragers, are capable of prey chemical discrimination. However, evidence for prey chemical discrimination in tuatara (Sphenodon), the only living representative of the order Rhynchocephalia (the sister group of Squamata) is not clear. Here, we compare responses to food chemical stimuli between Tuatara (Sphenodon punctatus) and a gekkotan lizard, the Common Gecko (Hoplodactylus maculatus). We found that tuatara showed the same responses as Common Geckos when presented simultaneously with a series of stimuli: they spent more time in the prey zone (odor of mealworms) than the pungency or control zones; they bit only the prey stimulus; and they showed similar latency to bite and give-up time as geckos. However, unlike Tuatara, geckos showed lingual sampling (tongue flicking) toward the prey stimulus. We showed that Tuatara could use chemosensory cues to detect prey in the absence of stimulus movement. Consequently, the coding of traits used to characterized tuatara as an outgroup in chemoreception studies should be revised.

Livestock grazing is a common land use across the western United States, but concerns have been raised regarding its potential to affect amphibian populations. We studied the short-term effects of full and partial livestock grazing exclosures on Rana luteiventris (Columbia Spotted Frog) populations using a controlled manipulative field experiment with pre- and posttreatment data (2002–2006). Despite a significant increase in vegetation height within grazing exclosures, we did not find treatment effects for egg mass counts, larval survival, or size at metamorphosis 1–2 years following grazing exclosure installation. Water samples taken in late summer showed concentrations of nitrite, nitrate, ammonia, and orthophosphate that were low or near detection limits across all ponds and years. The results of this experiment do not support a hypothesis that limiting cattle access to breeding ponds will help conserve R. luteiventris populations in our study area. Further research is needed to evaluate regional variation and long-term effects of grazing exclosures on R. luteiventris populations.

A new genus and species of extinct lizard is described from the Early Pliocene to Early Pleistocene deposits of Wellington Caves, New South Wales, Australia. The description is based on the anterior half of a left mandibular ramus that shows a suite of unusual characteristics. The fossil is referred to the Scincidae, based on its combination of a distinct coronoid process of the dentary and completely fused Meckelian groove, but it differs significantly from living scincids in several respects. The dental sulcus disappears posterior to the symphysis. The dentition shows slight enlargement of the teeth posteriorly, with the terminal tooth the largest. The new taxon has an exceptionally massive jaw, with a hypertrophied symphysis and coronoid region and the angle at the symphysis suggests a short, deep snout. The new species is not obviously related to any of the major extant scincid lineages.

Methods for obtaining plasma from anurans are unsatisfactory in that they are inadequately described, are difficult to perform, or are lethal to the subject. A lymph extraction technique involving temporary ligation is described that enables sufficient fluid to be obtained for analysis from frogs greater than 20 g. Lymph was more easily obtained from Bufo marinus than from the austral-hylids Litoria caerulea and Cyclorana australis. Lymph accumulation was faster in hydrated frogs or those with full bladders, whereas it was relatively slow in animals that had been dormant or that were dehydrated. Differences between the osmolality of lymph and blood-plasma were variable but slight; presumably the relatively high endothelial permeability of amphibians facilitates significant fluid exchange.

Information on the predation rate of Eastern Snapping Turtles (Chelydra serpentina serpentina) and Western Fox Snakes (Pantherophis vulpinus) on waterfowl, particularly ducklings, is minimal. Most information that exists focuses on the percent of waterfowl found in the diet of sampled turtles or snakes. Although this information is useful, it does not elucidate the potential effect of reptile predation on waterfowl populations by measuring predation rate (i.e., the number of sampled ducklings consumed by reptile predators). We attempted to determine this by tracking the fate of 448 day-old Mallard (Anas platyrhychos) ducklings from 1991–1994 on the Upper Mississippi River. A total of 120 ducklings were preyed upon during the study (26.7% predation rate). Of these, 13 were consumed by Eastern Snapping Turtles (2.9% predation rate) and four by Western Fox Snakes (0.8% predation rate). Predation rate by reptiles was lower than mammals and similar to that of fish and birds, but several depredations with undetermined sources could have been caused by Eastern Snapping Turtles. For a proper perspective on predation impacts on duckling populations, one must also consider the influence of habitat quality as it relates to the interactions of predation, food resources, and cover.

The tadpole of Telmatobius mayoloi from central Peru (Departamento de Ancash) is described based on specimens ranging from Gosner Stage 28–41. The tadpole of T. mayoloi is similar to other Telmatobius larvae with pond type morphology. Geographically closest to T. mayoloi are Telmatobius carrillae and Telmatobius rimac. The tadpole of T. mayoloi differs from the latter in reaching a maximum total length of 102.1 mm at Stage 38 whereas T. carrillae (maximum total length  =  99.20 mm at Stage 39) and T. rimac (maximum total length  =  77. 70 mm at Stage 36) are smaller. Furthermore, the snout of the tadpole of T. mayoloi is slightly narrower between the nares, and its tip is pointed compared to the broader snouts of T. carrillae and T. rimac. The tadpole of T. mayoloi is the fourth largest in Telmatobiinae; data comparing tadpole total lengths and adult snout–vent lengths of Peruvian Telmatobiinae are presented.

Rana sylvatica tadpoles have been shown to alter their oral structures in response to increased competition. The placement of mirrors on tank walls has previously been used to simulate increased density and to induce phenotypic changes in tadpole size and timing of metamorphosis. Here, we examine the effects of simulated overcrowding, induced with mirrors, on the oral structures of R. sylvatica tadpoles. Our data suggest that, although phenotypic changes caused by visually simulated competition are not as drastic as those produced by actual competition, they do occur. These alterations manifest in a failure to develop specific tooth rows.