In contrast to anurans, acoustic communication and hearing within Order Urodela is poorly understood. Several studies have documented sound production in a few salamander species; however, these studies did not examine auditory ranges of these salamanders simultaneously. Two-Toed Amphiumas (Amphiuma means) were used as a model to examine the ecological significance of sound production in salamanders. We conducted a series of behavioral trials to validate sound production in this species, and auditory-evoked potentials (AEPs) were measured to assess hearing abilities. Amphiuma means produced three unique broadband acoustic signals: low-, mid-, and high-frequency clicks. All acoustic signals were produced when A. means were placed in groups, but not when housed individually. The audiogram was relatively flat at 100–700 Hz; above this range, sensitivity declined with increasing frequency. No auditory responses were detected between 1.5 and 10 kHz. The dominant frequencies of the acoustic signals (2.7–11.7 kHz) were higher than the audiogram bandwidth, although the lower bound of lower-frequency clicks could effectively stimulate the auditory system for communication at short distances. Our study suggests that A. means utilizes acoustic signals during social interactions.

Observed life histories of animals reflect trade-offs among growth, reproduction, and survival that serve to maximize fitness under particular environmental regimes. Body size and age at first reproduction, as expressions of growth and developmental rates, are key trade-off elements. I estimated relative growth rates in three species of desmognathine salamanders that vary markedly in body size and habitat associations. Sampling was conducted in two assemblages of the species in the southern Blue Ridge of North Carolina. The species, ranked from larger to smaller, were Desmognathus quadramaculatus, D. monticola, and D. ocoee. An existing skeletochronological database served as a source of age estimates in salamanders for which standard lengths had been recorded. Body masses were estimated for these individuals from regressions of mass on standard length. Relative growth rates were estimated by the Gompertz model for growth in standard length and body mass, and by the von Bertalanffy model for growth in body mass only. In young salamanders, higher relative growth rates were recorded in the smaller species; this trend reversed at later ages wherein relative growth rates were greater in larger species over the remainder of the salamanders' life spans. In all three species in both assemblages, the maximum rates of absolute growth in mass occurred near or within the conjoint age range at first reproduction of the two sexes. Body size differences among these species result from differences in propagule size, growth rate, and (as one index of reproductive effort) age at sexual maturation. I present evidence that larger adult body sizes are a product of larger eggs, larger hatchlings, higher rates of growth, and lower reproductive effort in these and other species of Desmognathus, in southern Appalachian assemblages of the genus.

Anuran distribution patterns can be influenced by structural and dynamic characteristics of a habitat. In floodplains—such as the South American Pantanal wetlands—cyclic changes within terrestrial and aquatic biotopes can limit the distribution and occurrence of species. To test the influence of the habitat on the anuran community structure in the Pantanal, we recorded data on species composition and abundance at 30 sampling plots, from October 2006 to May 2007. We also recorded data on seven local environmental variables: water depth, distance to the nearest permanent water body, hydroperiod, leaf litter volume, plant cover by herbaceous plants, by monospecific stands of a bromeliad, and by shrubby/arboreal woody plants. We used multivariate statistical analyses to test for data correlation. In addition, we analyzed the degrees of associations of anuran species to habitat types. Our results revealed no influence of any of the analyzed environmental variables on the anuran species richness and abundance. However, species composition varied with vegetation structural complexity and the hydroperiod. Although most anurans were able to occupy different habitats along the environmental gradient, six species were strongly associated with specific habitats. The homogenizing effect imposed by floods on different habitat types might overshadow distributional patterns resulting from species-specific attributes, as well as from influences of other environmental factors.

Elucidating the ultimate and proximate mechanisms of melanistic color pattern formation has become an important focus of evolutionary biology. There are relatively few studies, however, examining the composition and architecture of pigment cells in melanistic reptiles. The typical color pattern of the skink Plestiodon latiscutatus, which inhabits the Izu Islands and Izu Peninsula of Japan, consists of brown dorsal coloration, five vivid yellowish white stripes, and a blue tail (in juveniles). We have observed melanistic morphs at a low frequency (<0.05%). Based on a histological examination of pigment cells, we determined that the melanistic morph of P. latiscutatus collected from Shikine in the Izu Islands possesses only dermal melanophores and lacks the xanthophores and iridophores seen in the normal coloration. This arrangement of pigment cells differs from the only other studied melanistic lizard, Sceloporus undulatus, in which the dark skin of the melanistic morph results from a simple increase in the density of melanophores relative to xanthophores and iridophores. Our findings indicate that associations between color pattern phenotypes and the expression of candidate color genes, such as Mc1r, are more complex than previously assumed; coloration in reptiles is controlled not only by cellular processes related to single pigment production but also by the differentiation of multiple pigment cells.

We studied female reproductive characteristics (clutch size, clutch frequency, egg volume, egg mass, and snout–vent length [SVL] at sexual maturity) in five populations of the Mexican endemic oviparous lizard, Sceloporus aeneus, from the Transmexican Volcanic Belt. Adult females showed a range in SVL of 40–60 mm. Mean clutch size was determined by counting vitellogenic follicles or eggs of females during the reproductive season, and was 6.6 ± 1.5 eggs. There was a positive relationship between clutch size and female SVL for all populations collectively. When analyzed by population, however, only two populations showed this relationship. Females lay at least two clutches during the reproductive period (from April to September). We found differences in the mean SVL of females with eggs and vitellogenic follicles among populations, but not in size-adjusted clutch size, egg mass, or egg volume. Our results showed life-history traits (SVL at sexual maturity, reproductive period, clutch size, clutch frequency) similar to those of other populations of this species, and to some small oviparous congeners that produce multiple clutches. Patterns in the relationship between SVL and clutch size were different among the five populations studied, which suggests that more studies on different populations are needed to understand the geographic variation exhibited by these traits. Our observations contribute to the knowledge of variation in the reproductive biology of this species.

We used microsatellites and mtDNA sequences to examine the mixed effects of geophysical, habitat, and contemporary urban barriers on the genetics of threatened Alameda Striped Racers (Coluber lateralis euryxanthus), a species with close ties to declining coastal scrub and chaparral habitat in the eastern San Francisco Bay area of California. We used cluster assignments to characterize population genetic structuring with respect to land management units and approximate Bayesian analysis to rank the ability of five alternative evolutionary hypotheses to explain the inferred structure. Then, we estimated rates of contemporary and historical migration among the major clusters and measured the fit of different historical migration models to better understand the formation of the current population structure. Our results reveal a ring-like pattern of historical connectivity around the Tri-Valley area of the East Bay (i.e., San Ramon, Amador, and Livermore valleys), with clusters largely corresponding to different management units. We found no evidence of continuous gene flow throughout the ring, however, and that the main gap in continuity is centered across the Livermore Valley. Historical migration models support higher rates of gene flow away from the terminal ends of the ring on the north and south sides of the Valley, compared with rates into those areas from western sites that border the interior San Francisco Bay. We attribute the break in ring-like connectivity to the presence of unsuitable habitat within the Livermore Valley that has been reinforced by 20th century urbanization, and the asymmetry in gene flow rates to spatial constraints on movement and east–west environmental gradients influenced by the proximity of the San Francisco Bay.

Many snake populations display seasonal variation in movement patterns in response to spatiotemporal variation in prey, mates, and other resources. Eastern Indigo Snakes (Drymarchon couperi) are federally threatened and endemic to the southeastern coastal plain of the United States. Although previous studies have described seasonal variation in D. couperi movement patterns at the northern limit of their range (southern Georgia), such information is currently lacking from peninsular Florida. We describe sex-specific seasonal variation in D. couperi movement patterns and space use in peninsular Florida across multiple temporal scales. We found that males made longer, more frequent movements, and had larger home ranges than females during the winter breeding season. Although movement frequency and distance were similar between sexes during the nonbreeding season, males still had larger home ranges. The degree of within-individual home-range overlap was consistent over time and not indicative of seasonal migrations between winter and summer habitats. Our observations of increased male movements during the winter are consistent with observations of breeding activity by snakes at our study sites, and across the species' range. The levels of winter activity that we observed for D. couperi contrast with the spring/autumn breeding seasons and low winter activity reported for other North American snake species. In contrast to our results, previous studies of D. couperi in southern Georgia found that both sexes exhibited the lowest rates of movement and smallest home-range sizes during winter, despite the occurrence of breeding activity. We hypothesize that differences in winter climate between these two areas allow for greater surface activity among snakes in peninsular Florida.

We tested the precision and accuracy of common measurements of snakes by repeated measurement of the heads and trunks of 10 preserved snakes and 10 live snakes by two groups of five people over 10-wk periods. The measurements produced values with variances and ranges related to the nature of the variable, the measurer, and the snake, but accuracy could not be determined. Reporting sizes of snakes to high levels of accuracy is therefore unwarranted. Measurements of head variables on preserved and anesthetized live snakes had similar levels of variance that approximate half the variance of the same measures on live, unanesthetized snakes. Conversely, measurements of snout–vent length (SVL) on both preserved and unanesthetized live snakes had about twice the variance of the same measures made on anesthetized snakes. Measurers differed for all measurements of preserved snakes and for all head measurements of live, unanesthetized snakes, more experienced measurers generally yielding higher precision. Conversely, measurers did not differ for most measures of anesthetized snakes. Our data support suggestions that the most repeatable measures of SVL are made on anesthetized snakes. Lengths of the head and lower jaw can be measured with relative precision on a snake in any condition. Head width and supralabial length have both inter- and intrameasurer variances high enough to make them unreliable measures of head size. We conclude that features of live snakes most commonly measured vary because they have no exact size. We therefore suggest a new convention for reporting sizes of snakes.

Two new species of Pseudopaludicola from midwestern Brazil are described. One of them, distributed in Bolivian and Brazilian areas within the Upper Paraguay and Upper Guaporé river basins, is characterized by the presence of a conspicuous conical tubercle on each heel, by T-shaped terminal phalanges, and so belongs to the formally recognized Pseudopaludicola pusilla group. The advertisement call is composed of a series of 14–720 notes with concatenated pulses—each lasting for 5–25 ms—and mean dominant frequency of 5071 ± 242 Hz. The second species, restricted to the southeastern-most region of the Brazilian state of Mato Grosso, is characterized mainly by a 2n = 18 karyotype, an advertisement call composed of series of 12–287 notes with concatenated pulses and mean dominant frequency of 4167.7 ± 287.5 Hz. A detailed description of the karyotype of this latter species is also provided.

A new species of the Hypsiboas pulchellus group is described from the Mantiqueira range, in the Município de Rio Preto, State of Minas Gerais, Brazil. We describe adults, tadpoles, and the advertisement call. The new species is morphologically similar to H. freicanecae, a species known from a few localities in the states of Alagoas and Pernambuco, northeastern Brazil, ∼1640 km north. Adults differ from H. freicanecae in having a slender body, smaller male size, larger calcar, and hidden surfaces of thighs and feet orange in life. Tadpoles have a ventral oral disc, with labial tooth row formula 2(2)/3–4(1), with one to three narrow posterior gaps on the marginal papillae located on the oral disc emarginations. The advertisement call is composed of two nonpulsed notes with dominant frequency at the second harmonic. The species is known only from its type locality, in an unprotected area.

The blindsnakes (Family Typhlopidae) are a diverse and widespread group of snakes with a near global distribution. They are known for their fossorial and cryptic habits making them one of the less frequently encountered groups of reptiles, which has resulted in little attention from researchers until recent years. With 44 currently recognized species, the blindsnake genus Anilios is the most widely represented snake genera in Australia. In this study, I describe a new species of Anilios known only from two specimens collected from offshore islands in the Kimberley region of Western Australia. I also discuss some recent taxonomic and nomenclatural changes in the genus, and return two recently resurrected species to their former synonymy. The new species can be distinguished from its congeners by a combination of morphological characteristics, in particular the absence of a caudal tail spine, midbody scales in 18 rows, ovate shape of rostral scale, position of nostril very close to the rostro–nasal suture, and path and termination point of the nasal cleft at the rostral scale. The description of a new Anilios species increases the number of currently recognized Anilios species to 45, a number likely to increase with further taxonomic study. The new species also further establishes the Kimberley region as an area of high species diversity and endemism.