Cane Toads (Rhinella marina) are an invasive species introduced to southern Florida, USA, and populations have spread northward through the state. Populations established near expanding edges of their distributions are predicted to have greater endurance, an indicator of dispersal capability, than longer established populations. To assess endurance, we collected Cane Toads from a northern (edge) and southern (core) population in Florida, placed them into a track, and prodded them to hop. The number of prods (taps), hops, and time spent hopping were recorded, along with the total distance each toad moved on the track. Edge population toads were less willing to move and did not travel as far in the track as those from the core population. To further evaluate endurance, we placed an additional set of toads inside a treadmill, where movement was required to maintain equilibrium. Toads moved on the treadmill until reaching exhaustion. We measured blood lactate levels from each toad upon exhaustion and during a 3-h recovery period. After the treadmill trials, there was no population effect on the distances traveled by toads. There was also no population effect on lactate levels of toads when reaching exhaustion or during recovery. Overall, Cane Toads from our sampled northern edge population showed no differences in endurance compared to those sampled from the southern population in this study. This finding may indicate that further dispersal is limited in the northernmost populations of the Cane Toad range in Florida. Furthermore, the reluctance of Cane Toads to move in the track trials may indicate that selective pressures differ for edge populations in Florida.

Climate change has historically resulted in the expansion, contraction, and shift of species ranges. High-latitude range limits in areas where no physical barrier prevents dispersal are of particular interest in light of species range contraction or expansion because they represent limits that may inhibit occupancy. MacArthur proposed that abiotic factors have a greater influence on species distribution approaching high-latitude range limits. We examined aspects of environmental structure that influence distribution of Common Five-lined Skinks (Plestiodon fasciatus) and are expressed in that species' population dynamics. Eight sites in the southern Shield region of Ontario, Canada were surveyed during the active season for P. fasciatus. We collected data on the canopy cover, slope angle, slope aspect, substrate, cover type, and temperature at sites where P. fasciatus was observed (microsites) and compared these data to the general site conditions (macrosite). We assessed population size using capture–mark–recapture methods and compared population age structure at eight sites to detect if there was a correlation between the characteristics of the macrosites, population size, and age structure. Abiotic factors were the primary limiting factors affecting distribution at high-latitude range limits of the species. Spatial ecology at the individual scale was influenced by sites with suitable thermal conditions. Our results confirm the importance of microsites with suitable thermal profiles as key habitat for ectothermic vertebrates at high latitudes. The influence of temperature as a limiting abiotic factor is expressed in population density of P. fasciatus. Conservation and restoration of high-latitude populations of ectothermic vertebrates should focus on ensuring thermal requirements of the species are met before other factors are addressed, as temperature is likely the single most significant limiting factor at high-latitude range limits.

We examined the phylogenetic relationships and evolutionary divergence of Phrynocephalus versicolor Strauch 1876, as well as the genetic diversity and population structure in Mongolia using mtDNA variation. Phrynocephalus is one of the most diverse genera within the Agamidae family, with confusing or controversial taxonomy. This resulted in several independent suggestions for subspecies designations within Phrynocephalus versicolor. As the most dominant and abundant reptilian species in the Mongolian Gobi Desert, Phrynocephalus versicolor is ecologically important within the food chain of the ecological system it inhabits. We used 77 samples from 9 populations of P. versicolor in central and southern Mongolia. We amplified and sequenced 522–base pair (bp) –long fragment of the ND2 gene and recorded moderate levels of sequence diversity (Hd = 0.74 ± 0.023, π = 0.035 defined by 97 polymorphic sites). We conducted phylogenetic analyses using of Bayesian inference, maximum likelihood, and median-joining (MJ) network analysis that resulted in four well-supported clades (A, B, C, D) among our Mongolian samples. All of these clades, except Clade A, were population specific. The genetic distance values (mean Fst = 0.768), and analysis of molecular variance (AMOVA) also showed greater genetic distances between these clades. We ran a time-calibrated phylogenetic analysis using a strict molecular clock model with a single fossil calibration. The estimated divergence times in this study were comparable with previous findings, for example, 1.8 million years ago (mya) (1.31–2.94) for the node (Bayesian posterior probability [BPP] > 1.0 and bootstrap > 98) from which Clade A and B originated. In conclusion, our findings showed that there are at least three genetically distinct subspecies, namely P. v. versicolor, P. v. kulagini, and P. v. hispidus, with one previously unknown clade/lineage.

Based on phylogenetic and morphological evidence, we describe a new species of Cyrtodactylus from Obi Island in the northern Moluccas, Indonesia. The new species is genetically and morphologically allied to the Melanesian species Cyrtodactylus papuensis but is distinguished by its larger body size, fewer midbody scale rows, deep precloacal groove in males, and enlarged nonpored femoral scales and pored precloacal scales arranged in a continuous series. The new species is also genetically divergent from C. papuensis (p-distances of 19.0%–20.1% in the mitochondrial NADH dehydrogenase subunit 2 gene). Four species of Cyrtodactylus are now known from the northern Moluccas, but it is likely additional species remain unrecognized.

We describe a new species of Knob-scaled Lizards of the genus Xenosaurus from the Sierra de Juárez of Oaxaca, México. Although this new species was identified as a distinct, undescribed lineage (and sister taxon to X. grandis) by previous molecular phylogenetic studies of the genus, we documented that it also differs from all of its congeners by a unique combination of scalation and color-pattern characters. The new species also is geographically isolated from all congeners and appears to have a geographic distribution limited to the vicinity of its type locality, between 1400 m and 1800 m of elevation, in the cloud forest belt of the Sierra de Juárez. Because the new species is a terrestrial, crevice-dwelling species generally ignored by humans and has a limited geographic and ecological distribution, we calculated its Environmental Vulnerability Score at 17, which places it in the middle of the high category of vulnerability to environmental degradation.

We review the taxonomic status of Oligodon arnensis (Shaw 1802) after examining all the name-bearing types of its synonyms, and evaluating morphological and biogeographic evidence. Oligodon arnensis sensu lato is widely distributed throughout Peninsular India, Sri Lanka, Pakistan, Nepal, Bhutan, and Bangladesh. We demonstrate that southern, eastern, and western populations in India represent three distinct species. Oligodon arnensis sensu stricto described from Arnee (now Arani), Tamil Nadu, southern India, is distributed in southern India up to 1500 m above sea level. Oligodon albiventer Günther 1864 and Simotes russellii var. ceylonensis Müller 1887 described from Sri Lanka closely match O. arnensis sensu stricto, and hence we treat them as junior synonyms. We resurrect Coluber russelius Daudin 1803 from the synonymy of O. arnensis, designate a lectotype, and restrict its type locality to Vizagapatam (now Visakhapatnam), Andhra Pradesh, eastern Peninsular India. Based on morphological differences we describe a new species from Kurduvadi, in the Deccan plateau of western India representing the western Indian population of O. arnensis sensu lato. We provide redescriptions for O. arnensis sensu stricto and O. russelius comb. nov. based on museum specimens, as both were named based on illustrations (iconotypes). Based on our update of the currently confirmed localities for O. arnensis, O. russelius comb. nov. and the new species, we discuss their biogeography and conservation status.