Hatchling American Alligators (Alligator mississippiensis) produced from artificially incubated wild eggs were returned to their natal areas (repatriated). We compared artificially incubated and repatriated hatchlings released within and outside the maternal alligator's home range with naturally incubated hatchlings captured and released within the maternal alligator's home range on Lake Apopka, Lake Griffin, and Orange Lake in Florida. We used probability of recapture and total length at approximately nine months after hatching as indices of survival and growth rates. Artificially incubated hatchlings released outside of the maternal alligator's home range had lower recapture probabilities than either naturally incubated hatchlings or artificially incubated hatchlings released near the original nest site. Recapture probabilities of other treatments did not differ significantly. Artificially incubated hatchlings were approximately 6% shorter than naturally incubated hatchlings at approximately nine months after hatching. We concluded that repatriation of hatchlings probably would not have long-term effects on populations because of the resiliency of alligator populations to alterations of early age-class survival and growth rates of the magnitude that we observed. Repatriation of hatchlings may be an economical alternative to repatriation of older juveniles for population restoration. However, the location of release may affect subsequent survival and growth.

The natural history of Prairie Kingsnakes (Lampropeltis calligaster calligaster) is largely unknown because of their secretive nature. We radio-tracked 10 adult Prairie Kingsnakes (six males, four females) for one complete active season to determine activity patterns and habitat use in an area in Illinois that included forest, grassland, agricultural fields, and roads. The active season extended from approximately April to mid-October. Home ranges of males averaged over four times larger than those of females and usually included the individual's hibernation site. Males and females had similar activity levels throughout the season, with no differences in frequency of movement or distance traveled per move. Snakes were underground at least 73% of the 574 times they were relocated, suggesting most activity is nocturnal. Collectively, kingsnakes completely avoided agricultural fields and showed a preference for grasslands, but females were strongly associated with grassland edges along roads. This association with roadside edges, and failure of Prairie Kingsnakes to cross roads, suggests that roads may be barriers to movement—an observation consistent with recent evidence that roads can be barriers to movement, negatively affecting snakes in ways other than via direct mortality.

Acris gryllus paludicola, the Coastal Cricket Frog, was described from Sabine Pass, Jefferson County, Texas, by L. W. Burger, P. W. Smith, and H. M. Smith in 1949. Additional specimens have not been reported or examined in the literature. At the time of its description, the association with Acris gryllus was parsimonious with the then-current understanding of the taxonomic position of the two species within the genus, A. gryllus and Acris crepitans. All subspecies within the genus were described within four years of each other, and all were subspecies of A. gryllus. The Coastal Cricket Frog is currently treated as a subspecies of A. crepitans but without an explicit treatment resolving its species level affinity. Seven individuals found on 19 May 2005 near the type locality are relatively smooth skinned; have reduced, or lack, anal warts; and retain ill-defined postfemoral striping; vocalizing males have pink-rose colored vocal pouches. Phenotypic comparison of the seven specimens fails to eliminate their inclusion in the species A. gryllus. Concurrent mtDNA sequence comparisons with A. gryllus from Florida and a series of A. crepitans from Texas confirm that the Coastal Cricket Frog is nested within the A. crepitans clade distinct from A. gryllus. We conclude that the original description of the “pink” frog is supported by examination of living specimens and have no evidence indicating that its subspecific status within A. crepitans should be questioned. Recent work within this genus has highlighted the need for an exhaustive study of the variation it presents rangewide.

Orientation is a key component to successful movements between habitats. We hypothesized that barren agricultural landscapes hinder the ability of frogs to orient and move between habitats. Specifically, we predicted that when presented with a choice between a short route through a hostile environment and a longer but safer route, individuals would select the one that entails the least risk. During a field experiment, we translocated 104 Edible Frogs (Rana klepton esculenta) into a recently harrowed field according to two treatments: the distance to their pond of origin (5–70 m) and the distance to a wooded hedgerow (10–60 m). The frogs' ability to orient toward the pond decreased with pond distance and increased with distance to the hedgerow, but we did not detect interactive effects. In addition, frogs were more successful in orienting toward the pond under high wind conditions. We have shown that both the configuration of the landscape and weather variables influence the movement behavior of amphibians in agricultural settings, and these may have important implications for population persistence.

Conservation of fauna breeding in vernal pools is challenging given their complex life histories. Many species, including the widespread North American Wood Frog (Rana sylvatica), require both aquatic and terrestrial habitat, yet insufficient information exists about movements between these environments, nor fine-scale selection patterns within them. To inform conservation planning, we conducted a radio-telemetry study of seasonal patterns of Wood Frog movements and habitat selection in southern Maine. Forty-three frogs were tracked an average of 25.6 days each, April to November 2003. In early spring, Wood Frogs generally selected damp leaf litter retreats on the margins of breeding pools. Following breeding, frogs selected forested wetlands (9.3% of the landscape) over forested uplands (90.7% of the landscape) in 75.3% of radio locations (N  =  544). Postbreeding movements from breeding pools to nearby, closed-canopy, forested wetlands ranged from 102–340 m (median 169m, N  =  8) and included stopovers in upland forest floors ranging from one to 17 days (median two days, N  =  7). Summer refugia were characterized by shady, moist (nonaquatic), and sphagnum-dominated microhabitats. In urbanizing areas, we recommend a shift from a core-habitat conservation model to a spatially explicit approach that considers pool-breeding amphibian habitat as a network of migration-connected habitat elements (e.g., breeding pools, upland forest, nearby forested wetlands). In our study, this approach reduced the amount of land potentially requiring protection by > 2/3 from that of core habitat models. With the rapid dissemination of GIS technology, spatially explicit planning for pool-breeding amphibians is increasingly feasible.

Reproductive cycles and patterns of sperm storage were examined for three regionally sympatric species of cold-temperate viviparous Australian skinks previously reported to have Type II reproductive cycles (autumn spermatogenesis and mating, with oviductal sperm storage (OSS) and spring ovulation). Histological examination of oviducts, testes and epididymides of winter- and spring-collected skinks were combined with data on monthly variation in gonad size (ovarian follicle diameter and testis length) obtained from museum specimens. Pseudemoia entrecasteauxii exhibited autumn spermatogenesis and mating, OSS over winter, and spring vitellogenesis and ovulation, concurring with previous studies for more southern populations. In contrast to previous studies from more southern populations, Niveoscincus coventryi and Hemiergis decresiensis displayed autumn spermatogenesis with epididymal sperm storage (ESS) over winter and spring vitellogenesis, mating and ovulation. Timing of mating and sperm storage patterns may vary geographically or possibly be plastic in response to local or annual variation in environmental factors. Autumn-onset vitellogenesis with OSS is hypothesized to be the optimal cycle for producing offspring earlier in the breeding season.

We review the geographic distribution of diploid and tetraploid populations of the Odontophrynus americanus species complex. Ploidy was determined using chromosome count as well as erythrocyte size. We found a complex geographic pattern of populations with different ploidy, including areas of syntopy and sympatry. The tetraploid O. americanus presents three disjunct population groups, which were isolated from one another by diploid populations. One of these tetraploid groups is distributed in central and eastern Argentina, southern Brazil, southern Paraguay, and Uruguay, with the other two population groups of the tetraploid O. americanus inhabiting southeastern Brazil, and northwestern Argentina respectively. We extend the distribution of both diploid Odontophrynus lavillai and Odontophrynus cordobae, and we present new records of three more allopatric diploid population groups, referred to here as Odontophrynus sp. Some of these population groups are associated with biogeographic regions. The karyotypes of the three currently known taxa of the O. americanus species complex are given. We report the occurrence of a naturally occurring triploid specimen and the first occurrence of B-chromosomes in the genus. Our review indicates that there is a complex distribution pattern of populations of different ploidy, including areas of syntopy and sympatry, and cytogenetic variability. This could indicate the presence of more species, occurrence of auto and allopolyploidy, and multiple origins of tetraploidy.

Little is known of Four-Toed Salamander (Hemidactylium scutatum) habitat use, despite the species' extensive range and elevated conservation status. We investigated species-habitat relationships that predict H. scutatum nesting presence in Maine at wetland and microhabitat scales by comparing microhabitats with and without nests. We created logistic regression models, selected models with AIC, and evaluated models with reserve data. Wetlands with nests were best predicted by shoreline microhabitat of Sphagnum spp., wood substrate, water flow, blue-joint reed grass (Calamagrostis canadensis), meadowsweet (Spiraea alba), steeplebush (Spiraea tomentosa), sensitive fern (Onoclea sensibilis), and absence of sheep laurel (Kalmia angustifolia) or deciduous forest canopy. Within occupied wetlands, shoreline microhabitat where nests occurred was best distinguished from available, unoccupied shoreline microhabitat by steeper shore, greater near-shore and basin water depth, deeper nesting vegetation, presence of moss spp. and winterberry (Ilex verticillata), and a negative association with S. alba, leatherleaf (Chamaedaphne calyculata), and K. angustifolia. These models of wetland and microhabitat use by H. scutatum may assist ecologists and managers in detecting and conserving this species.

Eighteen species of the frog genus Phrynobatrachus are recognized from Cameroon. We describe a new species from Mt. Nlonako in the Littoral Province of Western Cameroon. It was recorded during a six-year amphibian inventory at Mt. Nlonako and is known only from the type locality within a submontane rain forest at an altitude of approximately 450 m. Because of the low number of captures over the six-year period, Phrynobatrachus sp. nov. is considered a secretive leaf litter species. Diagnostic characters are a smooth skin texture, a distinct tympanum, rudimentary webbing, white spots on the lips extending to the hands and along the flanks, and a white interorbital line.

The Leopard Tortoise (Geochelone pardalis) is the largest of the southern African species and has a wide distribution encompassing a variety of habitats. There is a paucity of ecological information about Leopard Tortoises in these habitats. The goal of this study was to determine the population density, biomass, sex and age distributions, and morphometrics of Leopard Tortoises on farmland in the semi-arid Nama-Karoo. Because previous studies have found that body size distributions vary between mesic and xeric habitats, we expected that these Leopard Tortoises would show an increased body size compared to those from more mesic areas. In addition, we expected lower densities of Leopard Tortoises compared to more mesic areas. In total, 92 tortoises were caught with a male to female sex ratio of 1:1.3 that was not significantly different from unity. Adult females were significantly larger than males with respect to all morphometric measurements. Leopard Tortoises (excluding juveniles) were larger than those from more mesic areas. A population estimate of 57.6 ± 4.0 tortoises in a 5500 ha area was obtained using a mark-recapture sampling method and radio-telemetry. Density of tortoises was extremely low at 0.017 tortoises ha⁻¹, with a biomass of 0.002 kg ha⁻¹. Population density and biomass were lower compared with Leopard Tortoise populations in more mesic areas. This has implications for the understanding of fitness parameters and conservation of this species in semiarid areas.

Movement patterns and activity ranges were examined in a small population of Northern Pinesnakes (Pituophis melanoleucus melanoleucus), a rare species inhabiting a variety of habitat types. Information was obtained by implanting nine individuals with radio transmitters and monitoring them over a two-year period. Telemetered snakes exhibited a bimodal activity pattern with snakes moving more often during spring and late summer to early autumn. Snakes traveled an average of 273 m per move. Males moved greater distances than females during spring and movements during the autumn months were shorter than movements during spring or summer for all snakes. Northern Pinesnakes traversed large activity ranges averaging 59.9 ha with core centers of activity averaging 7.9 ha. Snakes made long movements across less suitable habitats (late successional forest habitats) to get to preferred areas (early successional field habitats). The mosaic of habitats comprising the study area may be responsible for large movement distances and activity ranges observed in individuals from this population. Telemetered snakes traveled longer distances to and from widely separated areas, resulting in this population needing more extensive, contiguous areas to support their biological needs under the current management regime.

A new species of diurnal gecko of the genus Cnemaspis is described from granite boulder habitats in gallery forests in the Monts Alantika and Hosséré Vokré, north of the Adamaoua Plateau in north Cameroon. The new species is most similar to the widespread species Cnemaspis spinicollis but differs from this and all other congeners in details of both scalation (single enlarged scale beneath the penultimate interphalangeal joint of digit IV of pes, absence of an enlarged, flattened preaxial metatarsal scale, absence of tubercles on the crown and beneath the ear) and coloration (pale, with little contrast between background color and series of distinct whitish dorsal markings, throat markings weakly developed). The discovery of several new reptile species from the Adamaoua Plateau and its outliers highlights the potential importance of the northern Cameroonian highlands as a center of endemism.

We analyzed the feeding ecology of four Thoropa miliaris (Anura, Cycloramphidae) populations from the Atlantic Rain Forest in Brazil. The diet was composed mostly of invertebrates, especially ants, beetles, grasshoppers, caterpillars, and spiders. Plant consumption was considered incidental because of its low frequency. Ants were the most frequent (range 70–100%) and numerous (range 54.9–63.8%) dietary items. In terms of volume, ants were the principal item at two localities (26.1% and 47.6%), being also important items for the other two areas (19.3% and 21.9%). Grasshoppers (20.1%) and beetles (22.8%) had the largest volume for two populations. There was a significant relationship of prey size and volume with frog jaw width in three of the four areas. Only in one area was this relationship not found, probably because of the high frequency with which small ants and termites were ingested. Many of the dominant prey taxa of T. miliaris were similar to those of other rain-forest frogs.

Exotic species colonize new areas through the processes of jump dispersal, population establishment, and diffusion dispersal. From 1962 to 1997, Mediterranean Geckos, Hemidactylus turcicus, were intentionally introduced multiple times into a science building on the campus of the University of Central Oklahoma, Edmond, Oklahoma. In 2005, we recorded 365 captures of 305 individuals. The population size was estimated to be 1005 individuals with a density of 478 geckos/ha. The population has dispersed a maximum distance of 200 m from the point of introduction which translates to a maximum rate of diffusion dispersal of 20 m/yr. These results support the hypothesis that range expansion of introduced Mediterranean Geckos has occurred because of multiple jump dispersal events, despite slow diffusion dispersal.

The Coastal Tailed Frog is one of the best studied headwater amphibians in the Pacific Northwest, yet we know very little about either its seasonal movements or its distribution within and among headwater basins. During August through October 2000–2002, we studied Coastal Tailed Frogs in 81 headwater basins from managed forests in the Stillman Creek watershed in southwestern Washington State. We found a significant association between tailed frog life stage and their locations along the stream axis: older life stages were located higher in the basin than younger life stages. Data from eight streams sampled in early and late summer 2002 support the hypothesis that adult Ascaphus truei move upstream several hundred meters during the low-flow period probably after having moved downstream to breed. We also found little evidence of tailed frog reproduction in small non–fish-bearing basins, which supports the hypothesis that breeding habitat in those basins may be limiting. To test these two hypotheses, we examined A. truei occupancy in 65 non–fish-bearing headwater basins ranging in size from first to fourth order in 2003 and 2005. Occupancy increased with basin order, and we found no evidence of reproduction (eggs, larvae, or metamorphs) in first-order non–fish-bearing basins. The length of the dominant stream thread in nearly all first-order basins was shorter than the distance adult A. truei moved between early and late summer. We suggest that a headwater stream must remain watered for several hundred meters during the dry season to meet tailed frog breeding requirements. Tailed frogs probably do not reproduce in most first-order non–fish-bearing basins in the Stillman Creek watershed because those basins are too small to reliably provide habitat suitable for oviposition and rearing of their early life stages.

Many reptiles exhibit temperature-dependent sex determination (TSD) in which the incubation temperature of the egg determines the sex of the embryo. The purpose of the current study was to examine intraspecific variation in temperature sensitivity during TSD. Two aspects of temperature sensitivity were evaluated in the Red-Eared Slider, Trachemys scripta: (1) clutch-specific variation in sex ratios produced at pivotal temperature and (2) variation in clutch sex ratios produced over the nesting season (e.g., early nesting season, midnesting season, late nesting season). Relatively large numbers of clutch sex ratios were examined from two or three time periods (e.g., early nesting season, midnesting season, late nesting season), during each of three nesting seasons. The results indicate that pivotal temperatures vary significantly among clutches, with clutch sex ratios ranging from all male to all female when incubated near the putative pivotal temperature. The results on seasonal variation in clutch sex ratios were more ambiguous. Data from two of the nesting seasons do not reveal significant variation between time periods. During the third nesting season, sex ratios from the first two time periods were not significantly different from one another, but the sex ratios from the very end of the nesting season were significantly different from those of the two earlier time periods. In summary, the results reveal a clutch-specific variation in pivotal temperatures, but the results from the seasonal study of sex ratios did not consistently reveal a shift in sex ratios over each nesting season.

Hyla camposseabrai Bokermann, 1968, was described based on specimens obtained at Maracás, State of Bahia, Brazil. It was subsequently considered as a subspecies of Hyla x-signata Spix, 1824, and currently it has been considered a synonym of Scinax x-signatus (Spix, 1824). In this paper, the status of the species is revalidated and the new combination Scinax camposseabrai is established.

The reproductive biology of Tantilla melanocephala was studied in eastern Amazonia, Pará, Brazil. Males and females attained sexual maturity at approximately twice the length (snout–vent length  =  SVL) of newborn snakes. Mature males had a larger tail length and more subcaudal scales than mature females, whereas females were larger (SVL) and had more ventral scales than males. Total length did not differ between mature males and females. Reproduction was not seasonal. There was no correlation between the number of vitellogenic follicles and oviductal eggs. The number of eggs was positively correlated with the female SVL. The data presented here indicate that the eastern Amazonia population differs from populations in southeastern Brazil in important morphological and reproductive aspects, including the mean number of eggs produced (mean  =  1.53), which was smaller in eastern Amazonian populations.

In many lizards, secretions of males are used in social behaviors, but it is almost unknown which specific chemicals are relevant in mediating these behaviors. Moreover, only a few studies have examined whether lizards can actually discriminate between different chemical compounds. We tested for differential chemosensory responses of female Iberian Wall Lizards, Podarcis hispanica, to two lipids (cholesterol and cholesta-5,7-dien-3-ol) found in femoral secretion of males, and which previous behavioral studies suggested may be relevant in female mate choice. The higher tongue-flick (TF) rates directed at cotton swabs containing these two lipids indicated that females detected and discriminated these chemicals from a control. There were no significant differences between responses to cholesterol and to the whole natural femoral secretion from males, probably because cholesterol is the major predominant component in secretions of males. The higher TF rates to cholesta-5,7-dien-3-ol than to cholesterol indicated that females discriminated these two steroids. Moreover, females seemed able to assess changes in concentration of cholesta-5,7-dien-3-ol and responded more strongly to higher concentrations. These results, together with the previous finding of female preference for areas scent marked by males with higher proportions of this steroid in their secretions, might support that cholesta-5,7-dien-3-ol was a “key” chemical that might be used by females to choose potential mates.

Early studies of genetic variation in the Red-Bellied Newt, Taricha rivularis, revealed only small amounts of genetic differentiation among populations. However, these studies sampled only a limited portion of the range of the species. To address this gap in our understanding, we measured genetic variation in T. rivularis using allozymes (45 loci) and mitochondrial DNA (mtDNA) cytochrome b sequences (366 base pairs). With the goal of surveying broadly for levels of genetic variation, four populations were sampled, three in the southern portion of the range, and one at the northern end of the range. Allozyme divergence throughout T. rivularis was low, with a maximum Nei's genetic distance of D_N  =  0.039. MtDNA haplotype diversity was similarly low, with only two haplotypes differing by a single base pair recovered among the four populations. Relative to other salamander species in western North America, T. rivularis shows weak genetic differentiation among populations.

Two localities in the Panaca Formation, Meadow Valley, Lincoln County, Nevada, have produced squamate remains that date to 4.9–4.7 Ma. Included are fossil maxillae of Crotaphytus sp. (Collared Lizards) and a dentary of Gambelia sp. (Leopard Lizards). To identify these fossils, diagnostic dental characters were used to distinguish the two genera. The toothrow of Crotaphytus exhibits wide, robust teeth and consists of mostly tricuspid teeth that show little or no recurvature. Gambelia dentition differs in having highly recurved, parallel-sided teeth throughout the toothrow, which contains more unicuspid than tricuspid teeth. Published records of valid Crotaphytus date to the middle Pliocene (3.7–3.1 Ma) and Gambelia date to the early to middle Pliocene (4.18–3.58 Ma). The Panaca Formation fossils described herein mark the oldest known record of both taxa.