Climate-related changes in breeding phenology have been demonstrated across a range of taxonomic groups. Amphibian phenology may be particularly susceptible to environmental variability, but studies have found species- and sometimes population-specific differences in the extent and direction of the phenological response to climate variation. I examined Spotted Salamander (Ambystoma maculatum) phenology metrics over the course of 10 yr to determine whether breeding phenology was sensitive to variation in temperature and precipitation in months immediately preceding or overlapping breeding migration. I examined these relationships for two early-breeding metrics (first arrival and 5% arrival) and one peak-breeding metric (median arrival) to determine whether early and peak breeders respond differently to environmental cues. I found that although there was no linear change in phenology across the 10 yr of this study, there were significant relationships between each of the three phenological metrics and temperature. Specifically, the two early-breeding metrics advanced as February low temperature increased, whereas peak breeding advanced as March low temperature increased. These results suggest that, within the range of variability seen across these 10 yr, temperature is a more important factor than precipitation in Spotted Salamander phenology, and if late winter temperatures eventually increase linearly at this site, then we might expect Spotted Salamander phenology to shift correspondingly. The results also suggest that it may be important to include multiple phenology metrics in future studies so that we can improve our overall understanding of the different layers of climate sensitivity that may exist and compare across studies more effectively.

We describe the larval external morphology and internal oral features of Crossodactylus caramaschii sampled in protected areas of the Atlantic Forest in southeastern Brazil. The tadpoles of C. caramaschii (Gosner stage 38) have an ovoid body in dorsal view and globular in lateral view, dorsal eyes, a ventral oral disc bordered by a single row of marginal papillae, with a wide gap on the anterior labium, and few and scattered submarginal papillae. The labial tooth row formula is 2(2)/3(1), with A-1 shorter than A-2, and P-3 shorter than P-1 and P-2. This is the first description of the larval morphology of this species and may help future studies on the intrageneric relationships of Crossodactylus.

Many snake species are elusive and difficult to study in field settings. As such, little is known about their population ecology despite conservation needs for many species. Advances in field techniques and statistical methods can improve our understanding of snake ecology. We used passive integrated transponder (PIT) telemetry to track Nerodia sipedon (Northern Watersnakes, n = 94) and Regina septemvittata (Queensnakes, n = 119) in six low-order streams in central Kentucky, USA from June to October 2016. We assessed snake density, spatial scale of detection, and detection probability using PIT tag relocations and spatial capture–recapture methods for linear habitats. Specifically, we modeled population density as a function of individual stream and land cover type, spatial scale of detection as a function of sex, and detection probability as a function of sex and time-varying covariates. Individual streams were a better predictor of snake density than land cover type; density estimates ranged from 6 ± 3 N. sipedon/km (mean ± standard error) to 107 ± 17 N. sipedon/km and 6 ± 5 R. septemvittata/km to 63 ± 10 R. septemvittata/km. Female R. septemvittata had a larger spatial scale of detection (55 ± 4 m) than male R. septemvittata snakes (40 ± 4 m). Spatial scale of detection did not differ between sexes for N. sipedon (females: 40 ± 4 m; males: 35 ± 3 m). The combination of PIT telemetry and spatial capture–recapture analyses can effectively estimate population densities and other population parameters for snakes and other reptiles and amphibians associated with linear habitats.

In viviparous organisms, the ability to feed while pregnant may mitigate energetic trade-offs experienced during the reproductive process and enhance fecundity. However, anorexia during pregnancy has been reported in many crotaline snakes. The potential costs and benefits of feeding while pregnant are not completely described in the literature, and experimental studies have been conducted in a limited number of taxa, rendering our understanding of the forces that may underlie the evolution of anorexia in pregnant snakes incomplete. Here, we examine the impact of food supplementation during mid to late pregnancy on mothers and offspring in a viviparous crotaline snake species, the Pygmy Rattlesnake (Sistrurus miliarius). Specifically, we offered multiple large meals to mothers held in outdoor enclosures and measured a suite of maternal and offspring traits including maternal body condition, offspring length and mass, maternal disease state, and offspring foraging behaviors. We focused on interactions between feeding, clinical signs of snake fungal disease (SFD), and the presence of its causative agent, Ophidiomyces ophiodiicola, in mothers. Pregnant females fed readily when offered food, but feeding did not impact offspring traits. Food supplementation significantly increased maternal postparturient body condition, but also increased clinical signs of disease in mothers and led to a significantly higher reproductive failure rate in the treatment group, particularly in mothers afflicted with SFD. Our results suggest that food supplementation during pregnancy may disrupt the reproductive process in pregnant rattlesnakes, and that such disruption is particularly pronounced in mothers suffering from SFD.

Lithobates johni and Lithobates berlandieri have, respectively, a restricted and a wide geographic distribution, and cohabit in the center of the Atlantic versant of Mexico. We analyze and compare the feeding habits of these two syntopic species, specifically evaluating differences in trophic niche breadth and overlap between sexes (L. johni = 35 females and 30 males; L. berlandieri = 25 females and 26 males) and seasons (L. johni = 45 from wet and 20 from dry seasons; L. berlandieri = 17 from wet and 34 from dry seasons). Both L. johni and L. berlandieri showed generalist feeding habits and were found to consume mainly arthropods; however, they also consumed vertebrates. In the wet season, L. johni males had higher stomach volume content than females, and L. berlandieri females had higher stomach volume content than males. In the dry season, L. johni females had higher stomach volume content than males, and a similar pattern was seen between sexes in L. berlandieri. Trophic niche breadth and dietary diversity were higher in L. berlandieri than in L. johni for both seasons. There was no trophic segregation between species in either season (wet or dry); however, we suggest that the differences in prey type consumed, dietary diversity, and trophic niche breadth might explain the coexistence of L. johni and L. berlandieri in the study area.

Body size, growth, and longevity in Northern Map Turtles (Graptemys geographica) from Dewart Lake in northern Indiana were studied from 1979 to 2016. Based on captures of 214 males (72 recaptures) and 99 females (40 recaptures), we generated von Bertalanffy growth equations which corroborated our growth curves based on counts of plastral growth rings and recaptured turtles. Females diverge from males in their faster growth by the end of their second season. Our oldest females were only 18–20 seasons old, and the oldest males were only 13–15 seasons old, suggesting a short generation time and a possible sexual difference in longevity. For the species, we detected no latitudinal pattern of size or age at maturity but found some support for a latitudinal increase in body size in accordance with Bergmann's Rule.

Phenological timing is of central interest to evolutionary ecologists because it is associated with fitness, but there has been limited study in animal groups with relatively secretive habits such as reptiles. This is especially true for the timing of hatchling behavior in wild reptile nests, likely attributable to few noninvasive methods for estimating parameters associated with egg hatching. We show that tri-axial accelerometers, small data loggers that measure rotation and inclination, can accurately quantify hatchling movement in wild reptile nests. In June 2018, we deployed an accelerometer in each of five freshly laid Snapping Turtle (Chelydra serpentina) nests in Algonquin Provincial Park, Ontario, Canada. In September 2018, nests were visited once daily to quantify the timing of hatchling emergence. The accelerometers worked as expected: there was statistically significant correspondence between the timing of accelerometer rotation in the nest (caused by movement of the hatchlings) and the timing of hatchling emergence. Furthermore, the number of hatchlings emerging from a nest was strongly and significantly correlated with the extent of accelerometer displacement. Our new technique allows new types of phenological data to be collected. It requires minimal effort and financial investment and thus is accessible to a broad range of research programs.

Caiman crocodilus apaporiensis has been of particular interest because of its clearly differentiated morphotype within the Spectacled Caiman complex. Information on the biology of C. c. apaporiensis is incomplete because of its restricted distribution in the inaccessible middle and upper Apaporis River in Colombia. I undertook an expedition to the middle Apaporis River basin in an attempt to validate the presence of C. c. apaporiensis through observations on morphometry, ecology, and ethnozoology. Previously described skull characteristics were clearly differentiable in both adults and subadults in the region. However, because many individual C. c. apaporiensis that were either captured or visually assessed were relatively small, some skull characteristics more closely resembled the more general C. crocodilus morphotype. Although data on population size and distribution of C. c. apaporiensis remain limited, information gleaned from local inhabitants indicates that the subspecies is common in the middle Apaporis River. Population parameter and molecular phylogeography studies could lead to management practices that would protect the genetic integrity of C. c. apaporiensis by minimizing subspecific interbreeding.

The anuran family Rhinophrynidae today comprises a single species restricted to southernmost Texas and Central America. Three extinct genera allied to this family are known from the Jurassic (Rhadinosteus) and Eocene (Chelomophrynus, Eorhinophrynus), whereas the sole extant genus Rhinophrynus is known from the latest Eocene (Chadronian) of Saskatchewan and the Pleistocene of Mexico. We provide the first records of the Rhinophrynidae from the Oligocene of eastern North America. From two of the oldest terrestrial vertebrate sites on the Florida peninsula (I-75, early Oligocene; Brooksville 2, late Oligocene), we have identified one nearly complete and several partial humeri, two radioulnae, two partial presacral vertebrae, three partial ilia, and one femur that are all referable to the Rhinophrynidae. These specimens are similar in size to the Eocene Rhinophrynus canadensis, smaller than the extant R. dorsalis, and might be distinguishable from both by features of the ilium and humerus. The presence of rhinophrynids during the Oligocene provides the first indication of change in the anuran fauna on the Florida peninsula during the Cenozoic.

Host-associated microbial ecology research is becoming a popular tool in conservation. For amphibians, there is recognition that environmental factors and anthropogenic activities can alter the composition and function of skin microbiotas. Despite growing studies on this topic, the environmental conditions and experimental methods that amphibians are exposed to vary among studies, potentially influencing our ability to develop generalizations. Using Northern Leopard Frogs (Lithobates pipiens), we investigated how the movement of individuals between housing conditions affected the amphibian skin microbial communities. In addition, we evaluated whether variation in experimental venue (e.g., culture pools, mesocosms, or laboratory) and time influenced the effect of a common antibacterial (sulfadimethoxine; SDM) on the skin microbiota. We found that the microbial community diversity decreased when tadpoles were transferred from culture pools to mesocosms and subsequently increased between mesocosms and the laboratory. When comparing the effect of SDM exposure on the skin microbiota of tadpoles across experimental venues (mesocosm and lab), there was no effect of SDM on alpha diversity. However, we noted opposing patterns between the control and SDM-treated individuals within the mesocosm and laboratory groups. In the laboratory, there were differences in the abundances of operational taxonomic units (OTU) while in the mesocosm there were differences in OTU turnover. Finally, we found that SDM treatment on amphibian microbial communities was consistent across time in the laboratory. Because researchers are integrating microbial assessments into our understanding of conservation biology, our results underscore the importance of standard housing conditions and taking into consideration that experimental design may yield variable results.