For small ectotherms, thermal conditions and habitat structure can drive local adaptations in behavior and habitat use. The water anole, Anolis aquaticus, is a semiaquatic lizard occurring along streams in lowland tropical sites, as well as at higher elevations with greater thermal variability. We studied their thermal ecology, habitat use, and behavior at a high- (~1100 m) and low-elevation (~sea level) site in Costa Rica to assess the relationship between thermal environment and behavioral ecology. We measured behavior through focal observations (rates of movement, head turns, and feeding) and recorded the range of environmental temperatures, body temperatures, air and substrate temperatures of perches, and habitat use (perch location relative to water’s edge and current, substrate, cover, and visibility). The low-elevation site had higher minimum temperatures and a smaller range of available temperatures. Body temperature and size varied with site and sex: low-elevation males had the highest body temperatures, and high-elevation males were largest. Individuals at the high-elevation site were less active, perched closer to the water’s edge (shorter horizontal perch distance), and more often used the ground or rocks near an eddy as a substrate than individuals at the low-elevation site. The temperature and habitat structure of water courses can manifest phenotypic differences in ecology and behavior.
.-The Arizona mountain kingsnake, Lampropeltis pyromelana, is a species of tricolor kingsnake distributed in disjunct patches of montane habitat in the western United States. Historical range maps were based on a small number of specimens, and the growing body of locality data on this secretive species has enabled a significant update to its known distribution. Multiple sources of citizen science data were used to supplement traditional data sources to more accurately delineate the range of this understudied species. We used citizen science data, primarily from iNaturalist and state-initiated surveys in Nevada and Utah, to show that the contemporary distribution of this species is different than historically purported-especially in Utah and Nevada. While there were some range reductions north of 40 degrees N latitude, there were also many range extensions in areas where L. pyromelana has recently been documented. With additional survey effort, more populations will likely be found, further extending the known distribution. Importantly, our research provides further evidence that citizen science is an effective source of data that can be used in conjunction with data from museum collections and government agencies to best inform conservation decisions, especially for elusive species.
The Columbia Spotted Frog (Rana luteiventris; CSF) is widely distributed across northwestern North America; however, declines in the southernmost populations, including those in Utah, have resulted in the consideration of this species for protection under the Endangered Species Act. In 1998, a conservation agreement and strategy for Utah's populations of CSF was developed and identified needed conservation actions, including range expansion. We repatriated CSF larvae during 2008-2010 from an extant population in the Provo River into Beaver Creek, a beaver-dominated stream, in the Weber River, a watershed where contemporary surveys indicate CSF have likely been extirpated. In 2011, CSF breeding was first observed in the repatriated population when 11 egg masses were documented in four depositional areas. After ten years of monitoring egg mass numbers, we consider the repatriation a success as this population continues to grow and expand with a high of 54 egg masses (2019) within ten depositional areas (2020). High quality habitat and the large number of CSF larvae transplanted likely attributed to the success of this repatriation. We used 1-2 day old CSF larvae (Gosner life stage 20-21) as the repatriation life stage that we believed would be the most likely to prevent the spread of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) from the known chytrid fungus positive donor site in the Provo River. Genetic testing of a robust sample (n = 59) of CSF tadpoles across the repatriation site in 2020 did not detect the presence of Bd, potentially indicating that we did not move Bd through the repatriation. Additional replicates would be required beyond this single experiment, however, to better determine if our transplant techniques are effective at preventing the spread of Bd.
The White Sands lizards of New Mexico are a rare and classic example of convergent evolution where three species have evolved blanched coloration on the white gypsum dunes. Until now, no geological replicate of the pattern had been described. However, one of the White Sands species, the lesser earless lizard (Holbrookia maculata), has been discovered to also inhabit the Salt Basin Dunes of Texas, where it has also evolved a blanched morph. We here present a first phenotypic and genetic description of the Salt Basin Dunes population of H. maculata. Phylogenetic inference based on a housekeeping gene (ND4) and a classic candidate gene in the melanin-synthesis pathway (Melanocortin 1 Receptor; Mc1r) shows the newly discovered population as an independent lineage, with no evidence of genetic parallelism in the coding region of Mc1r. Initial morphological data suggest that while this population displays convergent evolution in blanched coloration, there are divergent patterns in limb length and habitat use behavior between the gypsum environments. Our findings present the White Sands/Salt Basin Dunes as an exceptionally promising comparative model for studies of adaptation and convergent evolution.
Uluru is the more famous of the two namesake inselbergs found in Uluru Kata-Tjuta National Park (UKTNP). Uluru is roughly 10 km around its base, stands nearly 350 m tall, and can cast a shadow more than a kilometre long during the early morning and late afternoon hours. Additionally, there are many areas near the base of Uluru that receive nearly continuous shade throughout the day, which may also mean that these places could be buffered against extreme temperatures. This study investigated Uluru's influence on the climate at various distances from its base, and simultaneously assessed if the structure of the reptile community was related to the observed climatic variation. We used iButton data loggers to record the temperature and relative humidity at 26 sample locations surrounding Uluru. We used ArcGIS to map the path of Uluru's shadow and to determine when and how long data loggers recorded in and out of Uluru's shading influence. We found that the temperature and relative humidity were strongly influenced by Uluru's shadow, and that reptile assemblages were strongly correlated with the amount of time a sampled site was influenced by Uluru's shadow.
Species delimitation attempts to match species-level taxonomy with actual evolutionary lineages. Such taxonomic conclusions are typically, but not always, based on patterns of congruence across multiple data sources and methods of analyses. Here, we use this pluralistic approach to species delimitation to help resolve uncertainty in species boundaries of phrynosomatid sand lizards of the genus Holbrookia. Specifically, the Spot-tailed Earless Lizard (H. lacerata) was historically divided into a northern (H. l. lacerata) and southern (H. l. subcaudalis) subspecies based on differences in morphology and allopatry, but no research has been conducted evaluating genetic differences between these taxa. In this study, patterns in sequence data derived from two genes, one nuclear and one mitochondrial, for 66 individuals sampled across 18 counties in Texas revealed three strongly supported, reciprocally monophyletic lineages, each comprised of individuals from a single geographic region. Distinct genetic variation evident across two of these regions corresponds with differences in morphology, differences in environmental niche, and lines up with the presumed geographic barrier, the Balcones Escarpment, which is the historical subspecies boundary. The combined evidence from genetics, morphology and environmental niche is sufficient to consider these subspecies as distinct species with the lizards north of the Balcones Escarpment retaining the name Holbrookia lacerata, and those south of the Balcones Escarpment being designated as Holbrookia subcaudalis.
Buffel grass (Cenchrus ciliaris) has been established in Ulu?u-Kata National Park since 1968. To date, the influence of buffel grass on the Park's flora and fauna has been largely unassessed. The objectives of this study were to determine if buffel grass dominates vegetation communities at the base of Ulu?u and if buffel grass habitats are associated with lower reptile and amphibian species richness than endemic vegetation communities. We used vegetation transects to measure the amount of buffel grass and genera of endemic vegetation at 26 sampling locations around the base of Ulu?u. The vegetation survey data were paired with pitfall trap data from reptile and amphibian captures at the same sampling locations. Indicator species analysis and non-metric multidimensional scaling were used to analyse the vegetation and herpetofaunal community data. Our analyses determined five distinct vegetation communities around Ulu?u. At the base of Ulu?u, buffel grass dominated half of sampled areas and the rest of the inselberg's base was dominated by Themeda grasses. Buffel grass habitats had significantly higher herpetofaunal species richness than the Themeda habitats that dominated other areas at Ulu?u's base. Herpetofauna species richness in buffel grass-dominated habitats was also significantly higher than all vegetation communities except for Triodia-dominated habitats. These observations do not directly indicate that buffel grass presence promotes higher species richness of reptiles and amphibians since the observed patterns may be driven by factors such as proximity to breeding sites and abiotic variables not directly related to the grass itself.
In lizards, signal patches play a role in sexual selection, both in interactions among and between sexes. The size and shape of a signal patch may be used by males to determine if another individual is of the same or opposite sex. Males may confuse other males for females, or vice versa (i.e., sexual confusion) if the signal patches overlap in size and shape between males and females. As a result, the confused male may perform courtship displays to an intruding male or display aggression toward a female. Sexual confusion has been documented in Sceloporus cowlesi and is attributed to overlap in signal patch morphology between the sexes. But it is unknown how common this pattern is among other Sceloporus lizards. To make inferences about sexual confusion at the species level, we compare the morphology of signal patches between males and females in three species of Sceloporus lizards (S. consobrinus, S. cowlesi, S. tristichus) to test for adequate differences in signal patch size to prevent sexual confusion. Our results suggest that due to similarities in patch size between the sexes of both S. cowlesi and S. tristichus sexual confusion may be occurring.
Psilorhynchus sucatio (Hamilton) is redescribed based on the examination of 462 specimens, 13-67 mm standard length (SL). Psilorhynchus nudithoracicus Tilak & Husain is redescribed based on the examination of 97 specimens, 10-68 mm SL. Psilorhynchus gracilis Rainboth is placed in the synonymy of P nudithoracicus. Psilorhynchus hamiltoni, a new species and a member of the P. balitora species group, is described from the Tista River in West Bengal, India. It is distinguished from all other members of the P. balitora species group by having a well-developed lateral stripe, 6-7 poorly developed saddles that do not make contact with the lateral blotches, 7-11 lateral blotches, 34-35 lateral line scales, 9+8-9 principal caudal-fin rays, 36 total vertebrae, and the ventral surface between paired fins with a broad rectangular scaleless patch. A key to the species groups of Psilorhynchus is also provided, as are revised diagnoses for the P. balitora and P. nudithoracicus species groups.
We experimentally determined that the lizard Pedioplanis namaquensis engages in area-restricted searching (= ARS, localized searching after encounters with food) while foraging and that prey characteristics influence ARS. Single prey items were introduced to free-ranging lizards, and their subsequent search effort was characterized using first passage times (= FPT, time required for an animal to cross a circle of a given radius). Three prey types were used: termites, flies, and rice (control). FPTs were longer following termite encounters than following fly or control encounters. Control treatments produced no change in FPT, while lizards searching for termites showed the greatest change. The use by Pedioplanis namaquensis of ARS was most pronounced for the typically aggregated prey type.