The phylogeny of California Slender Salamanders (Batrachoseps attenuatus), which inhabits Northern California's Coast Ranges and Sierra Nevada foothills, was previously investigated by Martínez-Solano et al. (2007), who recovered a monophyletic species that contained five geographically cohesive major clades. However, a population isolate of B. attenuatus found in the Sutter Buttes, a geographically isolated volcanic mountain range within the Sacramento Valley, was not available in their phylogenetic analysis. We sequenced the ∼780-base pair segment of the mitochondrial DNA cytochrome b (cytb) gene used in Martínez-Solano et al. (2007) to examine the phylogenetic placement of this isolated population within the B. attenuatus complex. Our results, based on a single mitochondrial marker, indicate that the Sutter Buttes population of B. attenuatus is genetically distinct and falls within the Martínez-Solano et al. (2007) “East Bay/Sierra subclade” that, in turn, is nested within their “Eastern” major clade. Although we cannot accurately estimate how long the Sutter Buttes population has been isolated, B. attenuatus was likely able to colonize the Sutter Buttes during pluvial Pleistocene interglacials when more contiguous woodlands may have opened dispersal corridors across the Great Central Valley.

Coral snakes have restricted and specialized diets, and their semifossorial and aquatic habits make them difficult to observe or collect. As a consequence, there is limited information about many aspects of their biology, including genetic diversity. Microsatellite markers have been used to study genetic variability in nonmodel species, such as snakes. The aim of this work was to develop primers for microsatellite regions of the genome of Micrurus surinamensis, to test transferability potential to Micrurus lemniscatus and Micrurus paraensis, and to analyze the genetic diversity of those species. DNA of one specimen of M. surinamensis was sequenced on the MiSeq platform, and sequences were searched for microsatellite regions with 10 primers designed for regions having tetranucleotide motifs. Micrurus surinamensis (n = 12 individuals) presented from 5 to 13 alleles and expected heterozygosity ranged from 0.741 to 0.939. Eight markers were successfully transferred to M. lemniscatus (n = 38) and five to M. paraensis (n = 13). The probability of exclusion of paternity ranged from 0.997 to 0.999 for species, and the probability of combined identity was lower in M. surinamensis (8.41 · 10^-9). These are the first microsatellite markers to be used for studies of coral snake population genetics and conservation.

The Colubroidea includes all venomous and some nonvenomous snakes, many of which have extraordinary dental morphology and functional capabilities. It has been proposed that the ancestral condition of the Colubroidea is venomous with tubular fangs. The venom system includes the production of venomous secretions by labial glands in the mouth and usually includes fangs for effective delivery of venom. Despite significant research on the evolution of the venom system in snakes, limited research exists on the driving forces for different fang and dental morphology at a broader phylogenetic scale. We assessed the patterns of fang and dental condition in the Lamprophiidae, a speciose family of advanced snakes within the Colubroidea, and we related fang and dental condition to diet. The Lamprophiidae is the only snake family that includes front-fanged, rear-fanged, and fangless species. We produced an ancestral reconstruction for the family and investigated the pattern of diet and fangs within the clade. We concluded that the ancestral lamprophiid was most likely rear-fanged and that the shift in dental morphology was associated with changes in diet. This pattern indicates that fang loss, and probably venom loss, has occurred multiple times within the Lamprophiidae. There is also evidence that front fangs arose from a rear-fanged condition, and this has occurred independently more than once within the family. Our findings provide insight into fang and dental condition in relation to diet and support the hypothesis of a venomous ancestor for the Lamprophiidae.

Nonnative species are drivers of global change, affecting biodiversity and burdening society with economic costs. Effective management of an invasion relies on the ability to make accurate predictions about the target species' spread and impact. This requires knowledge of the target species' biology, making taxonomic validation critical. Even so, external morphology is still widely used to determine the species identity of novel invaders. Here, we show that a nonnative pipid frog population in Riverview, Florida, USA, initially identified as African Clawed Frog (Xenopus laevis), is a cryptic invasion of Tropical Clawed Frog (Xenopus tropicalis) and the only known nonnative population of this species. We used DNA sequence data and osteology from high-resolution microcomputed tomography to confirm this identification. Furthermore, we conducted field surveys to delineate the population's invaded range in Florida. We detected the presence of adult X. tropicalis at 22 sites and larvae at a subset of 12 sites, representing an occupied area of approximately 1,630 ha. Differing body size and physiology of these two species of Xenopus suggest considerable differences in their impact, spread, and potential geographic range.

Gopher Tortoise (Gopherus polyphemus) populations are declining throughout the southeastern United States. Range-wide conservation efforts include identifying populations that do not currently meet viability criteria but are suitable candidates for population enhancement. We investigated the potential role of head starting as a recovery tool by releasing hatchling and head-started yearling Gopher Tortoises as pairs (n = 28) into adult burrows in fall and comparing their movements and survival until winter dormancy. Head-started yearlings experienced higher predicted survival than did hatchlings (87.7% vs. 56.5%). Head-started individuals also tended to move greater distances between burrows and established dormancy burrows further from their release burrows, but the differences were not significant. Most individuals of both groups used a small number of closely spaced burrows, although hatchlings took longer than head-started individuals to establish their first burrow (11.3 vs. 4.4 d on average) and a higher proportion were depredated or censored before establishing a burrow (35.7% vs. 10.7%). The paired release design provides strong experimental evidence that head-started yearling Gopher Tortoises experience at least a short-term survival advantage over hatchlings, while exhibiting comparable fidelity to the release site. Soft-release pens were not necessary to promote high site fidelity in our study, but the decision as to whether or not to use them at other release sites may be dictated by the predator community and what is practical to implement. We contend that head starting shows promise as a recovery tool for Gopher Tortoises and that hard releases may be a worthwhile option for managers to consider.

Nesting is an essential, yet variable, reproductive behavior in most oviparous organisms. Although many factors conceivably influence nesting behaviors, it is unclear which factors strongly influence terrestrial nest timing in aquatic nonavian reptiles. As climate is changing rapidly, understanding the relative influences of biotic and abiotic factors on nesting behaviors may yield important information on future changes in daily and seasonal nesting activity. We collected hourly data to examine the significance of local weather conditions to the timing of within-season nesting activity in a large population of Painted Turtles (Chrysemys picta). We quantified nesting activity as the ratio of females who nested to all females who could nest in each hour, adjusting the size of the denominator to include the time required to shell a subsequent egg clutch. We then used zero-inflated models to identify potential weather predictors of presence/absence of nesting activity and strength of nesting responses (i.e., the fraction of turtles nesting that could nest). Higher temperatures and rainfall predicted stronger nesting responses, whereas lower temperatures and no rainfall predicted the absence of nesting activity, indicating that both temperature and rainfall are important cues in within-season nesting phenology. Our study enhances our understanding of abiotic influences on the terrestrial nesting behavior of aquatic organisms.

The cryptic behavior and appearance of some reptile species lead to difficulty in conducting effective surveys to estimate abundance. As an example, Horned Lizards (Phrynosoma spp.) often have a pattern of camouflage on the dorsum and they sometimes become motionless upon the approach of a human observer. However, they also venture onto roads to thermoregulate. When basking on a road surface, they are much easier to visually detect; hence, road-cruising surveys are an effective technique for surveying. We designed and implemented a survey protocol for a population of Texas Horned Lizards (Phrynosoma cornutum) at the Chaparral Wildlife Management Area (CWMA) in south Texas, USA. The protocol involved repeatedly driving a continuous 64-km survey route while visually scanning for lizards. Over the course of 17 survey days in summer 2015, we obtained 167 observations of lizards. To estimate lizard density, we used N-mixture models on datasets in which the route was divided into either 39, 77, or 117 segments (survey units) with lengths of 1,651, 836, and 550 m, respectively. Density estimates ranged from one to six lizards per 10 ha, depending on how the route was subdivided into segments and assumptions about the amount of roadside area surveyed. The density estimates were extrapolated to an estimated population size of 1,000–2,800 Texas Horned Lizards at the CWMA. Because this is a species of conservation concern, populations should be monitored within protected areas and perhaps elsewhere in landscapes where road surveying is possible.

Paleontological occurrences of helodermatid lizards (Helodermatidae) are relatively uncommon and scattered in the North American fossil record. A recently discovered concentration of vertebrate fossils was exposed in a karstic fissure filling in an active rock quarry in southwestern Oklahoma. Underwater screening of the ancient cave fill yielded numerous isolated and fragmentary skeletal elements of a diversity of small, and a few large, vertebrates including unexpected remains of Heloderma sp. as well as extinct large mammals (horse, peccary, Dwarf Pronghorn), indicating Pleistocene age. Radiometric dating of the locality is not possible because of the leaching, but fossils of the Prairie Vole, Microtus ochrogaster, from the locality help to constrain the age of the deposit between 1.21 Ma and 0.01 Ma. The fossils are the first of Heloderma in the Pleistocene of Oklahoma and the southern Great Plains. Based on taphonomic evidence and the relative abundance of rodent teeth, we infer that the fossils accumulated at least partly as the remains of vertebrates fed upon by Ringtails (Bassariscus; Procyonidae) and other small carnivorous mammals. The Pleistocene occurrence of Heloderma in the southern Great Plains of North American has potential implications for the paleobiogeography of the genus and begs further investigation of fossil herpetofaunas in North America.

Prey-handling behavior serves as an important link between the processes of prey capture, transport, and swallowing. Snakes, lacking limbs, have developed a series of complex behaviors for the purposes of subjugating and handling their food. Using captive individuals of the semiarboreal Boa constrictor, we describe for the first time a set of behaviors unique to handling dead, endothermic prey in an arboreal context. Faced with the challenges of having to support the body weight of both themselves and their prey, Boa Constrictors create a series of loops that allow the body of the snake to support the prey item while also allowing for intraoral transport and swallowing. These loops can be adjusted and repositioned during transport, positioning the prey so that the pull of gravity is in line with swallowing.

Temperature plays a critical role in growth and development of anurans. Here, we investigated thermal preference of tadpoles from a wide-ranging anuran, Hyla chrysoscelis, by establishing an ex situ thermal gradient in a laboratory setting. We collected 64 tadpoles with a mean (±SD) body length of 12.2 ± 2.1 mm (range, 7–15 mm). Mean temperature preference of tadpoles ranged from 12.9 to 30.0°C, and we found a positive relationship between temperature preference and body length. Although body length is only one component of amphibian development, its apparent link with temperature preference is an exciting area for further research in this species as well as other species. Furthermore, given the broad distribution of H. chrysoscelis, there is an opportunity to investigate how thermal preferences could limit population edges and how populations may respond to shifts in environmental temperatures.

Prior to both offensive and defensive striking, snakes can display notable differences in prestrike behaviors between offensive and defensive contexts. However, few studies have investigated strike movements during the different scenarios with which snakes are faced. To better understand how snakes strike, we measured the strikes of Western Ratsnakes (Pantherophis obsoletus; N = 11) presented with two different targets: one simulated predator (a gloved human hand) and one prey (pre-killed mice). For each strike, we recorded strike distance, duration, velocity (average and peak), acceleration (average and peak), and time to start mouth gape. In both encounters, ratsnakes displayed similar time to the initiation of a mouth gape while all peak performances were significantly different between strike types with performances being higher in defensive strikes. Defensive strikes took longer (mean = 122 ± 13 ms), reached greater distances (mean = 15.1 ± 1.7 cm), had higher maximum velocities (mean = 1.80 ± 0.11 ms^-1), and maximum accelerations (mean = 101.4 ± 15.2 ms^-2). Offensive strikes had much shorter durations (mean = 49 ± 5 ms), distances (mean = 4.3 ± 0.6 cm), maximum velocities (mean = 1.06 ± 0.10 ms^-1), and maximum accelerations (mean = 81.4 ± 18.9 ms^-2). The results for average performance measurements are similar to those for the maximum performance comparisons. Our results show that snakes can recognize and differentiate prey from threats and respond differently in each situation. Our results also show that predatory and defensive strikes are quantitatively and situationally distinct, should be treated as separate behaviors, and therefore should be evaluated and analyzed separately from one another.

Dietary studies are central to our understanding of organismal biology. We describe the diet and frequency of feeding in the Southwestern Speckled Rattlesnake (Crotalus pyrrhus). We used data from wild-caught specimens collected from six biogeographic regions (pooled to three regions for analysis) across the species' range in the United States that include Arizona, California, and Nevada, USA. Fecal material from 185 snakes yielded 104 prey items from 72 individuals, and palpation indicated recent meal ingestion in 36 of 174 individuals. The diet consisted predominantly of mammals (80.8%), in particular terrestrial squirrels (39.4%) and members of the heteromyid rodent genus Chaetodipus (26.9%). Male and female snakes exhibited similar diets and feeding frequency, but an ontogenetic shift occurred from primarily ectothermic (lizards) to endothermic prey (rodents and birds) and more frequent feeding. Consumption of ectotherms vs. endotherms appeared to be similar among biogeographic regions, but snakes from the Tinajas Altas Mountains, Arizona, preyed disproportionately on birds compared with other regions, and snakes from the Sonoran Desert-Arizona Upland region more frequently ingested recent meals than those from the California-Nevada region. Regardless of sex, size, and biogeographic region, snakes consumed fewer prey during the spring breeding season than during summer and autumn. We provide data on the diet of C. pyrrhus for testing further hypotheses regarding potential interspecific competition, dietary changes associated with climate change, foraging tactics associated with bird predation, competing behaviors during breeding season, and venom composition variation.