How have we managed to maintain our research partnership for more than 30 yr? We have come to think that personal respect for one another and trust that our core values and motivations are immutable have been key. Our partnership began with a project to gather much-needed information on Gopherus polyphemus (Daudin) (Gopher Tortoise). We soon realized that the species was in peril. The enormous pressures put upon species and habitats by the exploding human population of Florida fueled our desire not only to accumulate information about basic biology and ecology, but also information relevant to effective conservation and management. Our interest in the Gopher Tortoise expanded naturally to other inhabitants of the xeric uplands, particularly Plestidon reynoldsi Stejneger (Florida Sand Skink). This species inhabits the pyrogenic scrub habitat on the central ridges, which has been mostly lost to development. We present previously unpublished data that cautiously suggest that clear-cutting would be an effective tool for managing small habitat fragments when burning is not a reasonable option. Although we have worked closely with businesses and agencies, we understand that their motivations for facilitating conservation research are not necessarily the same as our motivations for conducting the research; however, we would not have been able to accomplish what we have without the cooperation and support of these entities. Regardless, destruction of xeric uplands has continued apace, and our inability to forestall species' decline is the most frustrating aspect of our partnership. Despite our frustration, we remain motivated by our conviction that we are doing the right thing.

Lepidosaurian reptiles (squamates and rhynchocephalians) comprise one of the world's most diverse groups of tetrapods, with most of that diversity found in regions of the world that once formed the supercontinent of Gondwana. In this special section of the Journal of Herpetology, we present both review and original studies on the evolution of lepidosaurs from Gondwana. In this contribution, we provide a brief introduction to those studies and also present metadata collected from the Web of Science on the progress of the study of lepidosaurian evolution. The latter indicate a substantial increase of research interest in multiple aspects of lepidosaur evolution worldwide, with special increase for lepidosaurs from Gondwanan continents. We conclude by setting some of the main goals we hope to achieve in the study of lepidosaurs from Gondwana in the near future.

Acrodont dental implantation is widely considered an important character for referring fossil material to Rhynchocephalia. Under its purest definition, acrodonty involves teeth being attached to the crest of the marginal bones without roots. A similar mode of tooth attachment is known in a variety of other reptile groups including some squamates and procolophonids. There is a lack of consensus on the definition of acrodont, how best to characterize tooth implantation, and the relationship between implantation and tooth replacement. Rhynchocephalians already are known to demonstrate variation in their mode of tooth attachment. Unambiguous acrodonty associated with little or no tooth replacement has been associated with Sphenodon, but it appears to have been the most widespread condition for much of the Mesozoic. A form of pleurodonty, where teeth are attached to the inside of the jaw bone with shallow roots, appears to be the plesiomorphic condition for both Lepidosauria and Rhynchocephalia. Jaws with anterior pleurodont teeth and posterior acrodont teeth appear to have been common for early rhynchocephalians in the Triassic, and Ankylosphenodon from the early Cretaceous of Mexico demonstrates that at least some later rhynchocephalians possessed continually replacing dentition, but identification of this trait requires inspection of internal anatomy. When cross-sections of teeth are unavailable or the lingual view of jaws is obscured, one cannot be 100% confident of acrodont implantation, and “acrodonty” should not be used as a single character to refer incomplete jaw material to Rhynchocephalia. Tooth implantation is a component that was highly variable in a once-diverse reptile group.

The diversity of extant squamates in South America is in deep contrast to the extremely scarce knowledge of squamates from that continent during the Mesozoic, particularly regarding terrestrial lizards. Here, we provide a review of the most recent advances in the knowledge of Cretaceous lizards from South America, focusing on named species (all from Brazil). These forms included scansorial, as well as cursorial taxa, likely displaying facultative bipedalism. In the case of Crato Formation specimens, only juveniles were reported so far, which raises questions about the role of taphonomic biases and community structure. Iguanians (acrodontans and non-acrodontans), as well as scincomorphs, are known since the Aptian/Albian. All iguanians had a broad Late Cretaceous distribution that, along with findings in the Early–Middle Jurassic of India, suggests an early radiation of the group before the final break up of Laurasia and Gondwana. Gondwanan regions may have played a fundamental role in the initial history of acrodontan iguanians despite the fact that, at least in South America, only non-acrodontans and scincomorphs are known to have passed through the Cretaceous–Paleogene boundary.

Australian Agamidae often are recovered from Australian Cenozoic fossil deposits but remain largely unidentified and unpublished. Accurate fossil identification could expand our understanding of the origin, distribution, evolution, and extinction of Australian agamid species over geologic time. We began to address this issue by critically examining skeletal morphologic features that were previously proposed for Australian Agamidae. We compared 60 morphological features (44 from the literature and 16 new features) for three taxa of the most speciose of the Australian agamid genera, Ctenophorus caudicinctus (n = 18), Ctenophorus isolepis (n = 20), and Ctenophorus reticulatus (n = 20). Of the 180 morphological features (60 per species) that were expected to be invariant for all specimens within a species, only 39 did not vary. All taxa have at least one unique feature that did not vary with ontogeny (i.e., apomorphy). Invariant features also are shared between two species or all three. Seventeen morphological features were invariant for all three taxa. In addition to invariant features, one to three morphological features varied within each species with either ontogeny or sex. We also found that few morphological features could be identified from disarticulated material. Given that the current museum collections are wholly inadequate for addressing these issues, larger collections of extant agamid skeletal material are needed to understand skeletal morphological variation. A fossil record of Australian Agamidae already exists; we just need to develop the tools to interpret it accurately.

The South American genus Homonota comprises 10 species of Broad-Headed Geckos that reach the austral limit for the Gekkota. Historically, morphological data have supported the monophyly of a group including Homonota and the Chilean genus Garthia, with the latter possibly embedded within the former. In contrast, molecular evidence indicates these two genera to be in separate clades and that Homonota is more closely related to the Leaf-Toed Geckos of the genus Phyllodactylus. Here, we analyze 592 morphological characters in Garthia, Homonota, and additional phyllodactylid geckos to evaluate their morphological similarities. Our results indicate that Homonota and Garthia share a great majority of both external and internal characters and are nearly indistinguishable on morphological grounds. These results are interpreted in the light of a recently published multigene molecular phylogeny, and they suggest the symplesiomorphic retention of many morphological states linked to miniaturization and terrestriality in Garthia and Homonota, and concomitant differentiation of the American Leaf-Toed Geckos.

El género Homonota del sur de América del Sur comprende diez especies de gecos de cabeza ancha, alcanzando el límite austral para los Gekkota. Históricamente, los datos morfológicos han apoyado la monofilia de un grupo que incluye Homonota y el género chileno Garthia, con la posibilidad de que el género anterior estuviese contenido en el primero. Por otro lado, la evidencia molecular reciente indica que éstos dos géneros forman dos clados separados y que Homonota está más cercano a los gecos con dedos en forma de hoja del género Phyllodactylus. En este trabajo, analizamos 592 caracteres morfológicos en Garthia, Homonota, además de otros de la familia Phllodactylidae con el propósito de evaluar las similitudes morfológicas. Nuestros resultados indican que Homonota y Garthia comparten la mayoría de caracteres externos e internos, y que son casi indistinguibles morfológicamente. Estos resultados son interpretados utilizando una filogenia molecular reciente de varios genes, y sugieren que Garthia y Homonota retienen una gran cantidad de simplesiomorfias, las cuales están asociadas a sus hábitos terrestres y a procesos de miniaturización, como también a su diferenciación de los gecos americanos con dedos de hoja.

We redescribe the holotype and only known material of the extinct teiid lizard Callopistes bicuspidatus Chani, 1976, from the late Miocene–early Pliocene of the Atlantic coast of Argentina. It would constitute a fossil record of the genus outside the present range of distribution restricted west of the Andes, but the characters used in the original description for the systematic assignation have had little attention and have been questioned in part. In this study, we confirm the generic assignation of these remains (as well as the validity of the species), based on characters different from those used in the original description. We also recognize many characters shared by Callopistes and the rest of the Tupinambinae teiids indicating the affinity of the genus to this subfamily. The paleoenvironmental conditions inferred from the accompanying vertebrate fauna for the late Miocene–early Pliocene of the fossil locality indicate that C. bicuspidatus exploited different environmental conditions than the extant species of the genus, especially regarding humidity and water availability.

En este trabajo redescribimos el holotipo y únicos restos conocidos del lagarto teido Callopistes bicuspidatus Chani, 1976, del Mioceno tardío–Plioceno temprano de la costa atlántica Argentina. Constituiría un registro fósil del género fuera de su actual rango de distribución, el cual se encuentra restringido al oeste de los Andes. Sin embargo, poca atención han recibido los caracteres utilizados para su asignación sistemática original, algunos de los cuales han sido cuestionados. En este estudio reconocemos distintos caracteres que confirman su asignación genérica y su validez específica. La mayoría de estos caracteres no fueron reconocidos en la descripción original. También reconocimos caracteres compartidos entre Callopistes y los restantes Tupinambinae indicando la afinidad del género con esta subfamilia. Las condiciones paleoambientales para el Mioceno tardío–Plioceno temprano de la costa Atlántica inferidas a partir de la fauna acompañante de vertebrados indican que C. bicuspidatus explotaba ambientes distintos a los de sus congéneres actuales, en particular en lo relacionado a la disponibilidad de agua y humedad.

Herein, we present a revision of mosasauroid lizards (basal aigialosaurs derived mosasaurids) from the Upper Cretaceous marine sediments associated with various Gondwanan landmasses. In stratigraphic terms, the Gondwanan fossil record of mosasaurs begins with basal mosasauroids from the carbonate platforms of the Middle East, in modern Israel. This record is followed by a dense Turonian record from Morocco and more rare specimens from the Turonian of Australia and Colombia. There is a substantial gap in the Coniacian and Santonian in Gondwana with only few known taxa, although the Campanian record from New Zealand is good (tylosaurines and mosasaurines), with additional rare specimens from Antarctica. Maastrichtian sediments from around the Gondwanan world are richly populated by a high diversity and density of all major clades of mosasaurid lizards. The mosasaurine Clidastes is currently not recognized from any Gondwanan marine deposit. The geographic and temporal patterns of distribution shown here are crucial for understanding the evolution of aquatic squamates not only in Gondwana but also globally.

Brazilian fossil snakes have had a rich and diverse record since the Late Cretaceous. Here, we provide an overview of the snake fossil record from Brazil, gathering all available data to reconstruct the diversity and distribution of taxa through time. Mesozoic snakes are scarce, represented by the putative ophidian Tetrapodophis amplectus, the snake Seismophis septentrionalis, and some undescribed material referred to ‘Anilioidea.' The Paleocene of São José do Itaboraí holds the richest and most-diverse Brazilian snake fauna composed of several taxa of madtsoids, ‘aniloids,' boids, ‘booids,' and caenophidians. Fossils from the Brazilian Neogene are reported for the Late Miocene of the Solimões Formation including boids, Colubroides, and an alethinophidian of uncertain relationships, Colombophis. Quaternary deposits yield a rich snake fauna represented by extant species such as boids and colubroids. The Brazilian snake fossil record is crucial for understanding issues about the early evolution of snakes and provides valuable insights into paleobiogeography, paleoenvironmental, and morphological studies.

The jaws of lizards commonly occur in Quaternary fossil deposits and have the potential to inform our understanding of recent changes in climate and environment. Frequently, however, interpretation of their taxonomic affinity is difficult because of either a lack of morphological characters and identifications or ones which are sometimes no more than subjective visual comparisons. Here, we evaluate the taxonomic affinity of a maxilla from the Holocene of Kelly Hill Caves (Kangaroo Island, South Australia) by comparing it to a sample of modern agamid lizards using computer models generated from X-ray computed tomography data and three-dimensional geometric morphometrics. To represent the shape of the maxilla, we used 22 fixed landmarks and 30 semi-landmarks placed at equivalent points on the three-dimensional surface files of the maxillae. Procrustes distances show that, with respect to overall shape difference, the fossil does not closely resemble Ctenophorus decresii, which is the only agamid currently present on Kangaroo Island. Preliminary comparisons to other candidate agamid taxa from southeastern Australia suggest instead that the fossil is most similar to Amphibolurus muricatus and Amphibolurus norrisi and least similar to Tympanocryptis lineata. Geometric morphometrics show promise as a more objective means of quantifying and characterizing shape differences. Reliable identifications, however, require sufficient specimen collections to adequately represent within-species variation (including ontogenetic variation).

As quantitative modeling of wildlife populations increases, the need for accurate and precise estimates of demographic rates for these populations also grows. Eastern Massasaugas (Sistrurus catenatus catenatus) are an imperiled rattlesnake species found mainly in the Great Lakes region of North America. We focused on an Eastern Massasauga population found on Beausoleil Island in Georgian Bay that was the subject of a 30-yr mark–recapture study for demographic analysis. We estimated multiple demographic values including annual adult survival, the temporal process variance of survival, population size, and population growth rate. Annual adult survival did not differ significantly between sexes (males 0.74; females 0.73). The process variance of annual adult survival for males was 0.006 and was inestimable for females. This is the first estimate of process variance for Eastern Massasaugas and one of the few such estimates for a snake species. The use of the process variance of survival in population prediction resulted in a large decrease in estimated extinction risk compared to use of the total variance of survival (3% and 21% extinction risk, respectively). Population size ranged from 35–77 (mean = 55), and realized population growth rate was equal to 1.02. Our analysis showed the Beausoleil Island population was stable up to the end of the study (2008). Demographic estimates can be used to guide management and conservation of this species.

Fires and volcanic eruptions produce ash that may negatively affect survivors of the disturbances themselves. Therefore, animals are expected to avoid areas covered by ash when possible. We tested this prediction by determining the substrate selection, ash vs. soil, in two insectivorous Liolaemus lizard species. We exposed each species to the type of ash it is most likely to encounter in its habitat: fire ash for Liolaemus lemniscatus and volcanic ash for Liolaemus pictus. We also determined the ability of these species to track insect scents in ash, as the effectiveness of scent tracking, and hence the ability to find food, may be reduced in ash. Contrary to our expectations, both species explored ash more than soil, and they were able to detect insect scents in ash. We concluded that at least shortly (e.g., days) after a disturbance involving ash production, surviving lizards may not avoid ash that may have negative impact on their health. Lizards would be able to find insects in substrates covered by ash by tracking their scents, however, suggesting that starvation may not necessarily be an immediate cause of mortality after a fire or a volcanic eruption.

Varanus rosenbergi females oviposit in nests excavated in termite mounds in summer, and hatching occurs the following spring after a seven-month incubation period. In this study, we characterized developmental features associated with the prolonged incubation of this species at Kangaroo Island in South Australia. Oviposition occurs shortly after limb buds have formed, and the subsequent pattern of organogenesis is similar to that of other lizards. Survival of eggs incubated at constant temperatures ranging from 26–33°C was 89–100%, whereas survival at 24°C and at 35°C was 0 and 14%, respectively. During the incubation period, mean ambient temperature at Kangaroo Island (14–15°C) is too low for successful reproduction, whereas mean temperatures in termite mounds (27–37°C) are substantially warmer and similar to the estimated mean incubation temperature (26–27°C). Therefore, successful reproduction by V. rosenbergi in southern Australia may be contingent on nesting in termitaria. Varanids, in general, have incubation lengths that are substantially longer than those of most other squamates, turtles, and crocodilians. We hypothesize that varanids have prolonged incubation lengths primarily as an adaptation to maximize hatchling fitness because their emergence from nests in the warm and/or wet season of the year following oviposition is the time most favorable for growth and survival. Other factors that may contribute to prolonged incubation are the developmental costs of a large brain and the energy costs associated with nest locations and substrates that may make emergence difficult for hatchlings.

Disease-associated mortality is a leading cause of amphibian declines and extinctions worldwide. Understanding the influence of land-management practices, like herbicide use, on amphibian immune defense traits could guide changes to improve conservation outcomes. Amphibians are partially protected from pathogens by two skin-associated immune defense traits: bacterial communities inhabiting their skin, and antimicrobial peptides secreted by the skin. Utilizing the Blanchard's Cricket Frog (Acris blanchardi), a declining North American amphibian species, as our model, we manipulated Rodeo™ aquatic herbicide concentration and the life stage at which Rodeo exposure occurred. We assessed juvenile survival, time to metamorphosis, juvenile mass, and skin-associated immune defense traits. We found a 37% decrease in survival of larvae exposed to 2.5 mg a.e. L⁻¹ (acid equivalent) compared to controls despite that this commercial herbicide formulation does not contain an added surfactant. Surviving larvae exposed to 2.5 mg a.e. L⁻¹ Rodeo had structurally different larval skin bacterial communities compared to controls. Larval Rodeo exposure did not carry over to postmetamorphic traits (juvenile mass, juvenile skin bacterial community, juvenile natural peptide secretions). Rodeo treatments did not affect time to metamorphosis or juvenile survival. Rodeo concentration had marginally significant effects on juvenile mass and the juvenile skin bacterial community. This study suggests glyphosate-based herbicide use may indirectly contribute to disease-related amphibian declines by altering the skin bacterial community that can provide pathogen resistance. Improving our knowledge of the influence of herbicide use on amphibians across life stages provides an opportunity for changes to application strategies to protect amphibian health or at minimum, lessen negative effects of the practice.

Biologists have increasingly recognized the importance of secondary forests as facilitators of passive landscape restoration and recovery of faunal communities in landscapes fragmented by farming. To evaluate the role of secondary forests as providers of food resources for anurans, we studied the diet of the Shovel-Nosed Treefrog (Diaglena spatulata) from five vegetation stages of tropical dry forest (pasture, early forest, young forest, intermediate forest, and old-growth forest) on the coast of Jalisco, Mexico. We examined the stomach content of 97 individuals using a stomach-flushing method. We found 14 different types of prey (Class or Order) in the frog's diet. Araneae, Lepidoptera, and Orthoptera occurred in frogs from all five vegetation stages. We recorded the highest number of prey types (11) in the young and intermediate forest stages, and the highest prey volume and prey frequency in stomachs from frogs inhabiting the old-growth forest. We found no difference in size or body condition of frogs among vegetation stages, but there was a positive relation between size and body condition with the volume of stomach content. Our results suggest that D. spatulata presents high dietary plasticity and that secondary stages of dry tropical forest contribute to the persistence of this species in human-modified landscapes.

Captive breeding and reintroduction have been increasingly used to restore endangered amphibians worldwide. Knowing habitat requirements for targeted species will help to enhance post release settlement and contribute to the success of reintroduction projects. To collect critical information on habitat requirements of the poorly documented Chinese Giant Salamanders (Andrias davidianus), we reintroduced 31 juveniles at two streams in central China and monitored them through radio telemetry from May 2013 to September 2014. We recorded 14 environmental variables twice a month (except during winter) at salamander locations and random locations. We also conducted transects systematically along streams to collect data on environmental variables and prey species. Habitat selection by salamanders was examined at two spatial scales: home-range scale and stream-reach scale. At the home-range scale, water quality variables were not different between salamander locations and random locations, although salamanders were found in deeper water, used larger boulders, and were closer to boulders. Regression models confirmed that presence of salamanders was positively associated with boulder size, river depth, and canopy cover but negatively associated with distance to boulders. At the stream-reach level, only the average water velocity was lower within home ranges than out of home ranges; however, no difference was found between core home ranges and out of home ranges. These results showed that large boulders were the most important variable selected by salamanders. Plenty of large boulders in the streams, together with evidences of postrelease growth of salamanders, indicate the two streams likely are providing suitable habitat for salamanders.

I describe a new species of Theloderma from two regions in Myanmar (Chin State in western Myanmar and Kachin State in northern Myanmar). Highly similar in appearance and size to Theloderma albopunctatum and Theloderma asperum, the new species differs by the presence of small, bilateral vocal sac openings absent in T. albopunctatum and T. asperum. Molecular phylogenetic analysis from two mitochondrial and four nuclear gene fragments infers that individuals are members of a unique genetic lineage within the T. asperum Complex.

The divergence of signals used in sexual selection and species recognition is thought to play an important role in speciation. As such, the striking diversity of dewlap color in Anolis lizards may have contributed to the diversification of this species-rich group. Whether the dewlap acts as a reproductive isolating barrier however remains unclear. We tested the prediction that the degree of dewlap divergence between the two closely related and highly polymorphic Hispaniolan trunk anoles Anolis distichus and Anolis brevirostris is correlated with genetic divergence and the frequency of hybridization in nature. We use integrative analyses of dewlap color variation and molecular genetics to investigate two pairs of localities where the species co-occur, including one pair of localities where the two species exhibit dissimilar dewlaps and a second pair of localities where they have similar dewlaps. At one site where species share similar dewlap coloration, we found evidence of hybridization and lower levels of genetic differentiation. At all other localities, however, including another site where species share a similar dewlap color, the species were genetically divergent with little evidence of mitochondrial and nuclear gene flow. Together, our results suggest that dewlap color is not consistently associated with reproductive isolation at the species level. Instead, site-specific factors may influence the dewlap's role in maintaining species boundaries.