Previous research suggests that some individuals of the red-backed salamander (Plethodon cinereus) in Virginia form socially monogamous relationships. We investigated if living together for 9 d is sufficient to establish such a relationship. In our first laboratory experiment, we tested two hypotheses: that increased familiarity between territorial males and female intruders would lead to (1) reduced aggression and (2) increased touching (conciliation) by the males, as expected in social monogamy. We posed the same two hypotheses in our second experiment for territorial females responding to male intruders. When residents and intruders first met, residents in both experiments spent more time in threat postures than they did 9 d later. Thus, familiarity led to decreased aggression toward intruders of the opposite sex. We then removed the now familiar first intruders and replaced them with unfamiliar second intruders. Aggression by residents in both experiments increased, suggesting that male and female residents can distinguish between a familiar and an unfamiliar intruder of the opposite sex. When we shortly thereafter removed the second intruders and, 2 d later, reintroduced the original first intruders, in both experiments residents maintained low levels of aggression. This suggests that they could remember the first intruders after 2 d of separation, even with the intervention of an unfamiliar member of the opposite sex. We found no difference in touching behavior for residents in either experiment. Thus, our first hypothesis (concerning reduced aggression) was supported while our second hypothesis (concerning increased touching) was not. Therefore, the formation of socially monogamous relationships may require longer than 9 d of living together and/or a ‘choice’ of partners, which would be possible in the natural habitat but was randomized in our experiments.

It is sometimes perceived that the cues affecting chorusing behavior in frogs are simple combinations of weather variables, and that closely related or sympatric species should respond to these cues in similar ways. We investigated these ideas by examining chorusing behavior in two species of tropical Australian microhylid frogs, Austrochaperina robusta and Cophixalus ornatus. Both species have small adult body sizes, are terrestrial breeding, direct-developers, and extensively co-occur in the Australian Wet Tropics. We used timed tape recorders to monitor calling activity over two breeding seasons (October to March) during 1995–96 and 2001–02. Calling activity was recorded at three times each night at seven locations along a 550 m transect. In the 2001–2002 seasons, dataloggers recorded temperature, humidity, and rainfall, and we calculated moon phase each night. Individuals of C. ornatus called more times per minute than individuals of A. robusta, and called at much more consistent levels across nights, in a seasonal pattern that closely followed a quadratic curve in both seasons. Calling activity by A. robusta males could occur at any level on any night of the breeding season, and varied greatly among nights. Principal components analyses for the 2001–02 data showed that 78.1% of variation in A. robusta calling activity could be due to factors common to the entire transect, while such factors could account for 62.8% of the variation in calling by C. ornatus. This result suggests that weather influences calling activity of A. robusta males more than of C. ornatus males. Canonical discriminant function analyses and partial rank correlations of the relationships between environmental variables and calling activity over the season indicated that initiation of calling in A. robusta males was strongly affected by rainfall, and continuation of calling by rainfall and humidity. Calling initiation in C. ornatus males was less correlated with weather variables, and appeared most strongly affected by humidity. Calling levels within species were correlated across the three recording times each night, but much less strongly than would be expected if caused by responses to weather. Calling activity also was correlated between species at each time of night, and a substantial proportion of this correlation did not appear to be caused by common responses to the weather variables we measured. We suggest that in both species weather conditions affect the probability of initiation of calling activity, and that initiation and continuation of calling are probably also affected by intraspecific and perhaps interspecific social facilitation.

Studies of lizard foraging modes and their correlates have led to major advances in our understanding of the evolution of lizard taxonomic, morphological, physiological, ecological and behavioral diversity. Although two basic foraging modes, ambush and active foraging, have been recognized, variability in foraging movements among species has led to controversies about their existence and the complexity and continuity of foraging behaviors. The variables central to the controversies are number of movements per minute and percent time moving. A third variable, the average duration per bout of movement, has been neglected. For 80 species I show that average duration, like the other variables, is continuous, unimodal, and lognormally distributed. Average duration is highly correlated with percent time moving, but only weakly with number of movements per minute. In discriminant function analysis and cluster analyses, average duration performed slightly worse at separating species by mode than percent time moving as a single variable and in combination with movements per minute. Because it is so highly correlated with percent time moving, average duration cannot be used as a third axis of a multivariable foraging space, but a variable indicating the variability of movement duration might provide new insights. Species for which modes were misclassified had percent time moving close to 10%. Average duration data support earlier reports that some gekkonids have unusually long-lasting movements for ambush foragers, yet remain immobile for long intervals between movements.

The aim of this laboratory experiment was to examine courtship behavior and reproductive success under two different perceived male densities in the Alpine newt (Triturus alpestris). Male behavioral patterns were similar at unbiased and male-biased operational sex ratios (OSR). Although the exhibition of luring behaviors is risky in the presence of other males, no difference in the frequencies of displays was found at the two male densities. Similarly, the responsiveness of females towards males and the success rate of the encounters (i.e., spermatophore transfer) were not explained by the OSR. Our results show that courting Alpine newts do not change their courtship patterns when other males are present and do not interact directly. However they are not necessarily opposed to those of previous experiments showing sexual interference and female aversion in male-biased OSR with possibility of interactions. These observations suggest that the evolution of courtship behavior may not be driven by the risk of sexual interference with other males prior to potential physical contact and that the benefits of breeding regardless of OSR can overcome the risk of competition at male-biased OSR.

Nocturnal car traffic often results in amphibian casualties, especially during rainy nights. The behavior of amphibians presumably influences their vulnerability to mortality on the road, but this hypothesis remains untested. We investigated the behavioral response of individuals of six species of amphibians on roads when confronted by an approaching vehicle. We first conducted a field study consisting of 50 night-driving surveys over 4 yr during which we recorded the behavior (i.e., moving or immobile) of frogs, toads, tree frogs, and salamanders encountered on a 20-km stretch of road. In an effort to tease apart the effects of headlights and the sound of motors on amphibian behavior, we carried out a field experiment on a test road where we exposed individuals to different car-associated stimuli. Here, we tested the hypothesis that simultaneous exposure to headlights and the sound of a car motor would elicit a stronger response than exposure to a single stimulus or a control. Based on the observations of the 2767 individuals in the field survey, immobility was the most common response to the approach of a car (mean probability of 0.82 of remaining immobile); the response differed across species but depended on the season of the survey (May–June vs. July–September). Similarly, the 91 individuals included in the field experiment were more likely to move during the control treatment than during any of the car-associated treatments. The combined stimuli elicited the strongest response, followed by the headlights-only and the motor-only treatments. Spring peepers (Pseudacris crucifer) tended to move more often than the other species we tested in the field experiment, which suggests they spend less time on the road and are less vulnerable to traffic mortality than other species. Both the field survey and field experiment consistently indicated that amphibians tend to remain immobile at the approach of a vehicle. This behavior highlights the vulnerability of amphibians to road traffic and should be considered in measures to mitigate road impacts.

We report on likely mixed paternity in a natural population of snow skinks (Niveoscincus mirolepidotus) from alpine Tasmania, Australia. This species is nonterritorial and males guard females after copulation, suggesting that guarding behavior has evolved to prevent rival mating of still-receptive females. To what degree does this mate-guarding prevent rival copulations? We sampled gravid females at random in the wild and looked for within-clutch mixed paternity among their offspring using amplified fragment length polymorphism (AFLP). Incorporating all visualized fragments, offspring band-sharing based on maternal bands was 0.94 (±0.05, SD), whereas for paternal fragments it was 0.54 (±0.46, SD). We then tested paternal band-sharing scores for all young of pairs against the mean score of the maternally inherited fragments to assess whether paternal genetic variation was larger than for a known single parent, hence, suggesting multiple sires. To reduce the risk of unequal sampling of polymorphic maternal and paternal fragments, we based our statistical tests on heterozygous bands only. Offspring band sharing based on maternal heterozygous fragments was on average 0.68 (±0.22, SD), versus 0.35 (±0.33, SD) based on paternally inherited fragments. In six of eight clutches (75%), at least one pair of young in a clutch had paternal scores outside of the confidence interval for a single parent (i.e., the mother). Thus, mixed paternity seems to be widespread in this population, despite prolonged postcopulatory mate-guarding by males.

Among frogs endemic to the Colombian Andes, the dendrobatid Colostethus palmatus has an exceptionally wide geographic distribution. We examined the patterns of variation in calls and genetic properties to determine whether this variation is associated with geographic barriers and distances between populations. We analyzed variation in advertisement calls and RAPD products in seven populations along a 346-km transect from south to north throughout the Cordillera Oriental covering an extensive part of the geographical range of C. palmatus. Populations of this species inhabit both slopes of the Cordillera Oriental, and are separated by a continuous ridge along these mountains. We found more inter- than intrapopulational variation. Four call variables and male snout–vent length exhibited clinal variation, generating a predictable geographic pattern which coincided with a climatic gradient of increasing moisture and seasonality. The genetic relations between populations are explained by their location on the Andes, particularly by the side of the slope. Differences between populations in four call characteristics and genetic distance were significantly correlated with linear geographic distances between populations on the same slope. We found evidence for genetic and bioacoustic differentiation between populations living on opposite slopes.

The annual growth line hypothesis predicts that a single, countable growth line is deposited annually in turtles. Support for this hypothesis is implied whenever growth line counts are used to estimate age in turtles. However, the hypothesis has not been thoroughly tested. We tested the annual growth line hypothesis by calibrating growth line counts against elapsed time in a population of red-eared sliders, Trachemys scripta elegans, in central Oklahoma. Thirty-one percent of all individuals (349/1129) had countable growth lines. The maximum number of growth lines that could be reliably counted was four. In each year of the study, the first turtles were captured early in March, yet the first new growth lines were not documented until late April. We recorded 1569 captures of 106 turtles that were captured in consecutive years and had countable growth lines throughout the study. Within these turtles, the annual growth line hypothesis was supported. Growth line counts agreed with elapsed time for 100 (94%) turtles. Three turtles appeared to add two growth lines in one year, and three turtles did not add a growth line in one year. We conclude that growth line counts can be used to age turtles in this population up to age four. However, we recognize several sources of error in growth line counts, and encourage researchers to conduct intensive sampling with repeated growth line counts from individuals.

The salamander Salamandra luschani is characterized by a tubercle, well documented in males, projecting from the dorsal surface of the tail base. To determine whether females have a tubercle containing modified secretory glands, we surveyed museum specimens and conducted a histological investigation of the dorsal tail base region. Our results show that most mature females do have a tubercle in the dorsal tail base region and even nontubercle females have hypertrophied glands in this area. Both granular and mucous glands within the tubercle are hypertrophied. The tubercle is smaller in females than in males. Underlying the hypertrophied granular glands in the tubercle region of some females are very large, previously undocumented, exocrine glands.

We used data from 10 years of continuous, concurrent monitoring of oak toads at eight isolated, ephemeral ponds in Florida longleaf pine-wiregrass uplands to address: (1) did weather variables affect movement patterns of oak toads?; (2) did pond hydrology and the condition of surrounding uplands affect pond selection by adults or juvenile recruitment?; (3) were population trends evident?; and (4) did a classical metapopulation model best represent their population ecology? Of 4076 oak toads captured, 92.2% were adults. Substantial (n ≥ 30 exiting juveniles) recruitment occurred only three times (once each at three ponds during two years). Males outnumbered females (average for all years 2.3:1). Most captures occurred during May–September. Adult captures during June–August increased with heavier rainfall but were not influenced by the durations of preceding dry periods. Movement patterns of metamorphs suggested that oak toads emigrated when moisture conditions become favorable. Pond use by adults was correlated with maximum change in pond depth (May–September). Juvenile recruitment was negatively correlated with minimum pond depth and the number of weeks since a pond was last dry, and positively correlated with the maximum number of weeks a pond held water continuously. The number of breeding adults and juvenile recruitment were highest at ponds within the hardwood-invaded upland matrix. The direction of most immigrations and emigrations was nonrandom, but movement occurred from all directions, and the mean direction of pond entry and exit did not always correspond. A total of 21.1% of individuals was recaptured; 13.3% of first captures were recaptured during the same year, and 7.7% during a subsequent year. Only 1.9% of captured oak toads moved among ponds, mostly within a distance of 132 m. We did not detect adult population trends over the 10-yr studied. Presence or absence at ponds in any given year was a poor indicator of overall use. We saw little evidence of local extinction or “rescue,” but were unable to determine whether juveniles returned to natal ponds or colonized new ponds for breeding as adults. Oak toad conservation can best be ensured by maintaining multiple ponds within a landscape to increase the probability of recruitment within the landscape neighborhood during at least some years and at some ponds, and to increase the likelihood of inter-pond movement.

The reproductive biology of the parthenogenetic lizard Aspidoscelis cozumela was studied from November 1994 to October 1995 on Cozumel Island, Quintana Roo, Mexico. Females exhibit a seasonal pattern with maximum reproductive activity during spring and summer (March to August) associated with day length. Clutch size averaged 1.8 (range 1–4) and was positively correlated with female body size. Females produced at least two clutches within the reproductive season.

We resurrect and redescribe Stenocercus torquatus from the Andes of central Peru in departamentos Junín and Pasco at elevations between 800 and 1800 m. This species was erroneously synonymized with Stenocercus crassicaudatus, which occurs allopatrically in the Andes of southeastern Peru, departamento Cusco. In addition to several scale counts, Stenocercus torquatus differs from S. crassicaudatus in having a black antehumeral collar, two black transverse bands anterior to the antehumeral collar, a shorter tail, the ability to change color, and an arboreal life-style.

A new genus, Cryptophyllobates, was recently described for a species of dendrobatid that was originally described as Phyllobates azureiventris. One of the distinguishing characters of this frog is the presence of dorsolateral stripes that end on the posterior back above the thighs. While conducting fieldwork in Acre, Brazil, I collected an unusual dendrobatid that transported all tadpoles in a clutch at one time; however, tadpoles of this species were more similar to Dendrobates than to Epipedobates. I subsequently discovered that this species is similar to Cryptophyllobates azureiventris and herein describe it as the second species in this genus. Molecular studies indicated that the new species and C. azureiventris are sister species and that they are closely related to some clades of Colostethus. Courtship of the new species was not observed, but tadpoles were found in a pool in a fallen tree, and adults were frequently seen in treefall gaps. Tadpoles are similar to those of Dendrobates in that they are predaceous, possibly as a result of convergence in behavior in response to development in similar restricted microhabitats.

A new species of gymnophthalmid lizard is described from the montane forests of the Península de Paria in northeastern Venezuela. The new species is one of three gymnophtalmid species known to be endemic to the region, and the fourth species of Riama from Venezuela. It is likely the sister species to R. shrevei of Trinidad, but can be distinguished from the latter species by having a nasoloreal suture, fewer scale rows encircling the midbody, and by having a higher number of transverse dorsal scale rows.

A new species of Hydrops is described. The new species has a disjunct distribution with regard to other species in the genus, occupying subtropical to temperate areas of Paraná and Plata River basins (between 19° and 28° 30′ S), from Pantanal in Mato Grosso do Sul, Brazil, through Paraguay and Paraná Rivers, with records in the Esteros de Iberá, Argentina. It differs from all congeners in the number of total ventral scales (ventrals plus subcaudals), number of dorsal scales and color pattern. Based on our data and those of previous authors, we present the variation in lepidosis and measurements, description of the hemipenes, and known distribution for the new species. Furthermore, a key for the identification of all taxa of the genus is presented.

Three new species of frogs allied to Rana megatympanum are described from Laos and Vietnam. One new species is from the Bolaven Plateau of southern Laos, a second is from central Laos and adjacent central Vietnam, and a third is from northern Laos. The three new species are distinguished from similar species by skin texture, the location of white spinules on the skin in males and females, spotting on the lips, body size, relative tympanum size, and unpigmented eggs.