We monitored 11 populations of eight species of Eleutherodactylus in Puerto Rico from 1989 through 2001. We determined relative abundance of active frogs along transects established in the Caribbean National Forest (El Yunque), Carite Forest, San Lorenzo, and in the vicinity of San Juan. Three species (Eleutherodactylus karlschmidti, E. jasperi, and E. eneidae) are presumed to be extinct and eight populations of six different species of endemic Eleutherodactylus are significantly declining at elevations above 400 m. Of the many suspected causes of amphibian declines around the world, we focused on climate change and disease. Temperature and precipitation data from 1970–2000 were analyzed to determine the general pattern of oscillations and deviations that could be correlated with amphibian declines. We examined a total of 106 tissues taken from museum specimens collected from 1961–1978 and from live frogs in 2000. We found chytrid fungi in two species collected at El Yunque as early as 1976, this is the first report of chytrid fungus in the Caribbean. Analysis of weather data indicates a significant warming trend and an association between years with extended periods of drought and the decline of amphibians in Puerto Rico. The 1970's and 1990's, which represent the periods of amphibian extirpations and declines, were significantly drier than average. We suggest a possible synergistic interaction between drought and the pathological effect of the chytrid fungus on amphibian populations.

The reproductive ecology and mating success of male Limnonectes kuhlii, one of the fanged frogs which are characterized by a suite of unusual sexually dimorphic traits (males have larger body, head, and fang sizes than females), were studied under natural conditions in subtropical Taiwan in order to clarify the role of sexual selection on male body size. There were no significant temporal peaks in the number of adult males or amplexed females observed along an 81-m transect of a small creek throughout a 3-mo study period. The nightly sex ratio was highly male biased. Over the study period, the distribution pattern of males showed a significant tendency toward clumping at oviposition sites (represented as oviposition sections of the creek where females laid eggs). During the nights, males usually showed a nonclumped distribution pattern along the transect, probably due to male-male interactions mediated through vocalization and physical combat, including vigorous biting. The calling sites of males were considered as breeding territories and sites of oviposition. Larger males often changed their nightly position along the transect, whereas smaller males remained at the same sites over the study period. The number of different oviposition sections in which each male was present over the study period ranged from 0–11 and was positively correlated with male body size. The number of matings by each male ranged from 0–9, and 42% of the males mated at least once. Male mating success was positively correlated with six male traits that included body size and the number of nights present. However, multivariate analysis revealed that a direct factor determining male mating success was the number of different oviposition sites which a male visited. This study also demonstrated that large-male mating advantage in L. kuhlii occurred indirectly through the size-dependent spatial movement pattern. A large body size in male L. kuhlii seems to have evolved through intrasexual selection (male-male competition by physical combat) in the context of a resource-defense polygyny mating system.

The green anole (Anolis carolinensis, Sauria: Polychrotidae) is the only native member of the neotropical genus in the United States and can be found as far north as North Carolina and Tennessee. Green anoles remain active throughout the winter in Tennessee, a rare behavior for reptiles at this latitude (35° 34′ N). In the Little Tennessee River population observed, individuals shift habitats in winter to a south-facing bluff where they aggregate in rock crevices at night and on cloudy days. The crevices provide thermal protection from air temperatures that routinely drop below freezing. Aggregations did not seem to provide any thermal benefits to lizards. Lizards emerged from the crevices when the sun illuminated their section of the bluff. The emergence order of lizards from a crevice was nonrandom; some lizards consistently emerged earlier than others. Position in the emergence sequence was determined by the depth of the lizard within the crevice, with shallow lizards emerging first. Lizards remained close to the same group of crevices throughout the entire winter and often returned to the same section of the bluff the following winter season.

Use of cover objects for hiding is a well developed behavior in reptiles, including snakes. Snakes sometimes aggregate under cover objects, which may reflect a shortage of suitable cover, very favorable conditions, social attraction, or simply chance. However, most studies of aggregation behavior have been conducted in the laboratory. In this study, I investigated the tendency of six species of snakes to aggregate under rocks in the field in southern Ontario, Canada. Most snakes under rocks were by themselves, but I found single- and mixed-species aggregations of up to four snakes. Although all species were involved in mixed-species aggregations, I did not find all possible combinations of species; no aggregations involved more than two species. Goodness-of-fit tests suggested that the pattern of aggregation sizes was well described by a geometric distribution, implying a nonrandom tendency toward aggregation. Nonetheless, because data were pooled over time, random occurrence of aggregation cannot be ruled out. However, aggregations were clearly nonrandom in another sense: individuals in aggregations tended to be the same size, perhaps indicating size-specific choice of rock and/or fellow snake. Careful field experimentation will be required to test these ideas.

We describe two new species of lizards of the genus Liolaemus from western Argentina. Both species belong to the petrophilus group and are easily distinguished from other members by a combination of chromatic and squamation characters. We used sequences of the mitochondrial cyt–b, 12S, and ND4 and the nuclear C–mos genes to infer the phylogeny of described species of the group. We found evidence for a monophyletic petrophilus group within the L. elongatus–kriegi complex. The petrophilus group includes Liolaemus petrophilus and two strongly supported clades, one containing the species distributed in the north, which includes one of the new species, L. talampaya; the second clade includes the species distributed in the south, including the new species, L. gununakuna.

Abstract: Many aquatic amphibians live in habitats with low visibility. In such habitats, chemical cues may be more reliable than visual cues for predator recognition. Adult perrenibranchiate graybelly salamanders, Eurycea multiplicata griseogaster, occupy clear-water streams with low levels of sedimentation and relatively few visual obstructions. In a previous laboratory experiment, graybelly salamanders distinguished between chemical stimuli from predatory fish (banded sculpins, Cottus carolinae) and nonpredatory tadpoles (Rana sphenocephala). In the present study, when only visual cues were available, salamanders did not distinguish between sculpins and tadpoles. Instead, they reduced activity in response to both predatory and nonpredatory heterospecifics in comparison to a blank control, indicating an alarm response to general disturbance rather than recognition of the specific predator, per se. To confirm that chemical stimuli are important under natural conditions, we tested whether graybelly salamanders in a natural stream habitat distinguished between chemical stimuli from sculpins, nonpredatory fish (stonerollers, Campostoma pullum), and a blank control. In contrast to their response to the nonpredator treatments, salamanders quickly moved away from the sculpin stimulus and then burrowed into the gravel substrate. Therefore, even for salamanders from clear-water habitats, chemical stimuli are more effective than visual stimuli for recognition of visually cryptic predators.

We redescribe Trimeresurus cornutus, a species that has not been reported for more than half a century, based on a recently collected live specimen from the Annamite Mountains of Central Vietnam. Besides new data on the distribution and habitat, we compare coloration and morphological data of the first known male of the species with the type specimen and a third known specimen from North Vietnam. We describe male genital morphology and analyze the systematic relationships of the species using external morphology, hemipenial morphology and molecular data. A phylogenetic hypothesis, based on four mitochondrial genes, suggests that the species is most closely related to Protobothrops jerdonii. The external morphology and hemipenial morphology are consistent with this placement. Based on the few specimens available, Protobothrops cornutus comb. nov. exhibits a very patchy distribution, with an altitudinal range reaching from 150–2000 m.

Anuran larvae evacuate their feces through the vent tube, which communicates with the posterior intestine and opens to the exterior. In the dextral configuration, the vent tube extends posteriorly from the body wall to the right side. The morphology and microanatomy of the dextral vent tube configuration were studied in various species classified into three categories: (1) marginal external tube, (2) nonmarginal external tube, and (3) without external vent tube, but with an external aperture in the posterior wall of the body. These dextral configurations were compared to medial vent tube configurations in Orton larval types 2, 3, and 4. Although vent tubes show greater morphological diversity in the dextral than in the medial condition, the histological organization in all cases is based on the same tissues (dermis and epidermis), and, thus, the medial and dextral configurations are fundamentally similar. Part of the cloaca located in the pleuroperitoneal cavity has a region covered by ciliated epithelium, which suggests that it is derived from the proctodeum. Cilia remain in the cloaca, until at least Gosner Stage 34. The rectus abdominis muscle fibers are orientated in a different direction relative to the cloaca in tadpoles with different ecotypes.

Salamandra salamandra has an unusual mode of reproduction. Females retain eggs in their oviducts and give birth to aquatic larvae or, in some populations, to fully metamorphosed juveniles. We investigated how variation in the birth size of larvae of five different sibships of S. salamandra affected larval survival, larval growth rates, time to metamorphosis, and size at metamorphosis under different food and temperature conditions. Maternal effects, via the effect of larval birth size, attenuated throughout development in all environments but still affected metamorphic traits at lower temperatures. Larval developmental time was negatively correlated with larval birth size and positively correlated with size at metamorphosis. After controlling for the effect of larval birth size, broad-sense heritabilities were obtained for residual values of metamorphic traits, indicating that enough genetic variability exists at lower temperature environments and that responses to selection of metamorphic traits are possible. The size at and the time to metamorphosis were phenotypically and genetically correlated. Since both traits presumably affect fitness, genetic dependence between size and time to metamorphosis may act as a constraint on adaptive evolution through antagonistic pleiotropy. Mass-specific growth, time to metamorphosis, and size at metamorphosis were plastic under different temperature and food conditions, but no significant sibship × environment interaction was found for any trait. In addition, significant cross-environment correlation for size at metamorphosis with respect to the food gradient indicates low potential for the adaptive evolution of reaction norms to heterogeneous food environments.

The genus Lachesis Daudin, 1803 was partitioned into six geographic groups to evaluate the taxonomic status and phylogenetic relationships among these groups. Characters of external morphology and hemipenial anatomy were evaluated. Results obtained through the phylogenetic and statistical analyses support recognition of the Central American species L. melanocephala and L. stenophrys as distinct species, whereas the South American L. muta is recognized as monotypic, without further differentiation in subspecies. These results provide further evidence of the independence of the Central American and South American lineages and are congruent with other studies based on molecular data.

We describe two new species of the leptodactylid frog genus Physalaemus from the lowlands of western Ecuador. Both species belong to the P. pustulosus species group. They differ from other group members, except P. coloradorum, in their smaller size. They can be distinguished from P. coloradorum by their less tuberculate dorsal skin and a more depressed loreal region. The new species differ from each other markedly in advertisement call. Although the ranges overlap, body size, flank gland length, and parotoid gland length (relative to snout-vent length) are also significantly different. Overall the new species are similar in color patterns and body shape; they are difficult to diagnose from each other with morphological characters.

A new species of the Eleutherodactylus unistrigatus group is described from forests near Oxapampa, Peru, at elevations of 2050–2200 m in the Cordillera Oriental in central Peru. The new species differs from all described species by having an extremely long, acuminate snout and a red (white in preservative) longitudinal stripe on the posterior surface of each thigh.

A new species of rattlesnake is described from the upper elevations of Cerro Tancítaro in Michoacán, in the western portion of the Transverse Volcanic Cordillera. This diminutive rattlesnake appears to be most closely related to several species also occurring at high elevations in Mexico and the southwestern United States including Crotalus intermedius, C. pricei, and C. transversus. The Tancítaro species is most similar to C. transversus, but differs in aspects of lepidosis and color pattern.