Organisms may reduce the risk of predation by responding to chemical cues from predators. Recent research shows that many species vary their antipredator response depending on the diet of the predator. We examined the responses of three plethodontid species of salamander (Plethodon cinereus, Eurycea bislineata, and Desmognathus ochrophaeus) to chemical cues from a shared snake predator (Thamnophis sirtalis). At the time of the study, Eurycea bislineata showed overlap in habitat with Plethodon cinereus and Desmognathus ochrophaeus, but Plethodon cinereus and Desmognathus ochrophaeus showed no overlap with one another. Each salamander species was presented with chemical cues from snakes fed Desmognathus ochrophaeus (TS_Do), Eurycea bislineata (TS_Eb), and Plethodon cinereus (TS_Pc). Plethodon cinereus avoided both TS_Pc and TS_Eb, whereas Eurycea bislineata avoided only TS_Eb. Conversely, Desmognathus ochrophaeus did not avoid any cues from the predator, regardless of the diet of the snake. When we analyzed activity data, we discovered that Plethodon cinereus showed higher activity levels when exposed to TS_Pc than to the other cues. Individual Eurycea bislineata did not vary their activity to the three treatments. Lastly, Desmognathus ochrophaeus, which did not avoid any of the cues from the predator, were more active in response to TS_Do and TS_Eb than to TS_Pc. These results show that phylogenetically related prey species may employ a variety of antipredator behaviors and suggest that discrimination of predator diet-cues may be linked to the degree of microhabitat overlap among the different prey species at the time of our study. Our study also highlights the importance of using multiple response variables when examining antipredator behavior.

Evidence for ecological character displacement must include correlation between the morphological character in question and the function of that character in the organisms' environment. Examination of the cranial skeletons and jaw components of sympatric populations of Plethodon cinereus and Plethodon hoffmani correlate well with the sympatric shift in diet in these two species relative to their respective allopatric populations. This hypothesized relationship between cranial features and diet is consistent with ecological character displacement. A biomechanical model predicts a stronger, slower jaw in sympatric P. cinereus and a faster, weaker jaw in P. hoffmani relative to their respective allopatric populations. Inherent in this model is the assumption that no differences in the jaw muscles exist. Here we test this assumption using data on jaw muscle mass and tooth number in sympatric and allopatric populations of P. cinereus and P. hoffmani. Our findings indicate significant differences between species, but no consistent pattern of character displacement in these structures. We discuss the consistency of our data with the previously proposed biomechanical model and alternative hypotheses.

The pattern of growth, age and size at sexual maturity, and sexual size dimorphism were determined for 30 Indian bullfrogs, (Hoplobatrachus tigerinus) reared in out-door terraria, from metamorphosis to 3 years of age. Size and the growth rates for males and females were comparable throughout the study. For SVL, annual mean growth rate was very high in the first year (7.31 cm) but declined in the 2^nd (2.70 cm) and 3^rd (0.53 cm) years. For body mass, annual mean growth rate was similar (∼68 g) for the 1^st and 2^nd years but declined (24.31 g) in the 3^rd year. In general, growth was faster during summer than in winter months. After attaining maturity, growth rate declined for both sexes. Some males attained sexual maturity in the first year (10 months old), while the remaining males and all females matured at the end of 2^nd year. In naturally occurring breeding populations, males tend to be smaller than females. This difference appears to be due to the presence of males and females of different age groups rather than differences in early growth rates.

We performed intrusion experiments and observed the course of 13 male-male agonistic interactions to gather information on the communicative role of visual signaling in the Amazonian tree frog Hyla parviceps. To obtain information on the ecological context potentially associated with visual signaling, we performed nightly censuses of calling activity and tested whether males differentially used microhabitats in relation to properties that affect both acoustic and visual communication. Among seven behaviors performed by males, two were visual displays. Foot-flagging displays and advertisement calls were used at a similar rate and at similar distances between interactants. Arm-waving displays were less common and used at a closer range than foot-flagging displays. The analysis of a dyadic transition matrix revealed that foot flagging significantly elicited foot-flagging displays by the opponent frog. Furthermore, resident males produced more arm wavings and calls than intruders, although the latter difference was not significant. We conclude that male H. parviceps respond to intruders by combining advertisement calls and visual displays, and that visual signals may serve functionally as a spacing mechanism. Comparing the properties of perches used by calling males with a random sample of available perches indicates that males prefer perches surrounded by denser and higher vegetation. Furthermore, calling activity occurred during or shortly after heavy rains and coincided with calling activity of several co-occurring species of hylid frogs, which probably decreases the locatability of calling males. We suggest that, under these conditions, the simultaneous production of auditory and visual signals may momentarily increase a sender's locatability when a conspecific receiver is detected.

The use of relocations, repatriations, and translocations as amphibian and reptile conservation strategies has received much debate. In the case of endangered species, their use may outweigh the potential negative consequences. We performed an experimental repatriation of the eastern massasauga (Sistrurus catenatus catenatus), which has experienced range-wide population declines and extirpations. The experiment included measures to minimize negative conspecific effects to the donor populations as well as inter-species effects on the release and donor sites. Snakes released during late July had lower mortality rates, larger home ranges, and gained more mass than snakes released in early September. The July release cohort also successfully reproduced, while no breeding activity was observed with September release snakes. Results of this study suggest that repatriation may be a viable method of restoring eastern massasauga populations. We hope the methods and conservation measures used in this experiment will serve as a template for future repatriations.

We studied habitat selection by the litter-dwelling gecko Sphaerodactylus nicholsi in the Cabo Rojo National Wildlife Refuge in southwestern Puerto Rico to determine how this small diurnal species exists in an apparently xeric habitat. We divided the 240 ha refuge into 956 quadrats each measuring 50 m × 50 m and selected 60 quadrats at random to search for geckos. The 60 quadrats yielded 33 discrete locations with sphaerodactylids that we called occupied sites. Occupied sites were located beneath the dense canopies of broad-leaved evergreen trees and were completely shaded. The average area of an occupied site was 103 m². We paired each occupied site with a nearby random site and compared relative sphaerodactylid density and habitat variables to determine features important in habitat selection. Occupied sites were in dense shade of evergreen trees and contained trees that produced large seeds or fruits; random sites commonly were exposed to sunlight, either directly or filtered through a thin deciduous canopy. Occupied sites had significantly lower daytime substrate temperatures, more leaf litter, less grass, less bare ground, and an order of magnitude more sphaerodactylids than the random sites. The four random sites with sphaerodactylids also had dense shade. Despite its small size, diurnal habit, and apparent vulnerability to dehydration, S. nicholsi thrives through selection of the scattered patches of relatively mesic environment within a xeric landscape.

The smallest tortoise, Homopus signatus, is inadequately protected, and information on its reproductive ecology can facilitate effective conservation. We combined X-ray radiography and ultrasonography to assess the reproductive status of free-ranging female Homopus signatus signatus during August–September 2000 (n = 30) and September–October 2001 (n = 29). Females produced only single-egg clutches but can produce more than one clutch in a season. Most (ca. 75%) of the females were gravid each spring, so H. s. signatus probably has a seasonal pattern of egg production. This pattern may be related to the seasonal climate; summers are hot and dry, yet winter rainfall is moderately predictable. Females were gravid from August through October, but further analyses are necessary to characterize the entire reproductive season and quantify clutch frequency. Large females produced large eggs, compared to eggs of small females. The smallest gravid female had a straight-line carapace length of 84.1 mm while the largest female measured 110.0 mm. Compared to gravid females, nongravid females were in poorer body condition (body mass and mass relative to carapace length) only in 2000, when there was lower rainfall and plant availability than in 2001. The difference in body mass approximated the mass of one egg. The low clutch size and fecundity suggest that populations have low intrinsic rates of natural increase. This plus their limited range and specific habitat requirements make H. s. signatus vulnerable to anthropogenic impacts.

We used radio-telemetry to study the movements and habitat use of Western toads (Bufo boreas) in the Targhee National Forest in southeastern Idaho. Eighteen toads (10 male and 8 female) that bred in a seasonally flooded pond, were fitted with radio-transmitters, tracked, and their movements mapped and analyzed with global positioning and geographic information systems. We also analyzed their patterns of habitat selection at micro- and macro-scales by comparing sites used by toads with randomly selected sites. After breeding, two male and six female toads left the breeding pond and used terrestrial habitats extensively. Male and female toads showed different patterns of movement and habitat use, although all toads seemed to behave in ways that reduced loss of body water (e.g., such as traveling on nights of high humidity). Male toads traveled shorter distances from the pond than females (581 ± 98 m and 1105 ± 272 m, respectively). Female toads used terrestrial habitats extensively and were selective of cover types (e.g., shrub) that provided greater protection from dehydration. Female toads also preferred certain habitat edges and open forests over forests with closed canopies or clearcuts. Information from this study can assist land managers in establishing protective buffers and managing forests for the protection of toad populations.

A critical variable in both ecological and conservation field studies is determining how many individuals of a species are present within a defined sampling area. Labor intensive techniques such as capture-mark-recapture and removal sampling may provide estimates of abundance, but there are many logistical constraints to their widespread application. Many studies on terrestrial and aquatic salamanders use counts as an index of abundance, assuming that detection remains constant while sampling. If this constancy is violated, determination of detection probabilities is critical to the accurate estimation of abundance. Recently, a model was developed that provides a statistical approach that allows abundance and detection to be estimated simultaneously from spatially and temporally replicated counts. We adapted this model to estimate these parameters for salamanders sampled over a six year period in area-constrained plots in Great Smoky Mountains National Park. Estimates of salamander abundance varied among years, but annual changes in abundance did not vary uniformly among species. Except for one species, abundance estimates were not correlated with site covariates (elevation, soil and water pH, conductivity, air and water temperature). The uncertainty in the estimates was so large as to make correlations ineffectual in predicting which covariates might influence abundance. Detection probabilities also varied among species and sometimes among years for the six species examined. We found such a high degree of variation in our counts and in estimates of detection among species, sites, and years as to cast doubt upon the appropriateness of using count data to monitor population trends using a small number of area-constrained survey plots. Still, the model provided reasonable estimates of abundance that could make it useful in estimating population size from count surveys.

Abstract: A new species of Pseudoeurycea is described from cloud forests of the Sierra Madre Oriental of Puebla, México. The new species is distinguished from all other Pseudoeurycea by its small size, stout body, short tail, large nostrils, presence of characteristic glandular convergent ridges on the pelvic region and the tail, and by its distinctive limb structure, with very small hands and feet that are extensively webbed and bear prominent but short and pointy middle digits. The only apparent close relative of this species is P. praecellens, from which it differs by the position and distribution of the dorsal and caudal glands, body proportions, nostril size and coloration. All specimens of the new species were found in cloud forest, under a canopy of Liquidambar, Quercus, and arborescent ferns, as well as in a coffee grove. The elevational range for the species is narrow, between 905 and 1400 m, unusually low elevations for Pseudoeurycea.

We describe a new species of Cochranella from the Montañas de Mache in the Chocó Ecoregion of the lowlands of northwestern Ecuador. The new species is placed in the Cochranella granulosa group and can be distinguished from all other species of Cochranella by having: (1) white parietal and visceral peritonea; (2) a snout that is gradually inclined in lateral aspect; (3) conspicuous dermal folds, and large, white tubercles on ventrolateral edges of Finger IV, forearms, elbows, tarsi, Toe V, and heels; (4) fleshy, tuberculate, ∩-shaped cloacal fold; and (5) dorsum green with small yellow dots in life. The new species shares several characters with C. daidalea, C. resplendens, C. savagei and C. solitaria, including dermal folds with white tubercles on the arms and legs, snout gradually inclined in profile, and cloacal ornaments. Finally, we briefly discuss the characters that define the Cochranella granulosa group.

We describe a new species of Chiasmocleis from the municipality of Una, in the Atlantic Rainforest of southern Bahia, northeastern Brazil. The new species is the smallest member of the genus and is characterized by having an ovoid body; a truncate snout in dorsal view, rounded snout in profile; no webbing on hands and feet; fingers lacking disks, toe tips slightly expanded; fingers and toes weakly fringed (less fringed in females), with few lateral dermal spines in males and none in females; the dorsal surface of body and limbs with dermal spines in males, absent in females; in preservative, color on dorsum uniformly grayish brown, paler brown on dorsal surface of limbs; posterior surface of thighs with a white, longitudinal line; and belly boldly marbled in brown and pale cream.

We describe two new species of Proctoporus and a new species of Euspondylus (all from central Peru, Departamento de Huánuco, 2545 to 3010 m elevation). The new species are distinguished from all species presently assigned to Proctoporus and Euspondylus by unique characteristics of pholidosis, morphometrics, and color pattern. A key to the Peruvian species of Proctoporus and Euspondylus is provided. The current allocation of species to Proctoporus and Euspondylus may not reflect the phylogenetic relationships of the species under consideration. Based on the available data there appears to be no evidence to justify the separation of these genera. However, because of nomenclatural problems that would arise from synonymizing the two genera (e.g., producing a secondary homonymy in the case of Proctoporus guentheri Boettger and Ecpleopus guentheri O'Shaughnessy), we chose to retain the two genera until phylogenetic information is available.

We describe a new species of rainfrog of the Eleutherodactylus fitzingeri species group from central Panama. This species is most similar to members of the E. melanostictus subgroup and can be distinguished from other members of the E. fitzingeri group from Lower Central America by a combination of characters, including a large supraocular tubercle, barred thigh pattern, a granulate venter, marked sexual dimorphism in the tympanic membrane, and basal toe webbing. We analyzed a data matrix of 24 allozyme, morphological, and karyological characters, following the phylogenetic analysis of Miyamoto (1986), and included four additional characters. The 12 species of the E. fitzingeri group are included, in addition to the new species. The relative phylogenetic position of two species, E. emcelae and E. phasma, are proposed for the first time. The new species is hypothesized to be a member of the E. melanostictus subgroup, which contains the predominantly montane species E. melanostictus, E. rayo, E. emcelae, E. monnichorum, and E. cuaquero.