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“Texas offers the opportunity to observe lizard diversity like no other part of the country,\" writes Laurie J. Vitt in the foreword to Texas Lizards. From the moist eastern Piney Woods to the western deserts, lizards can be found in every part of Texas. The state has forty-five native and six naturalized species of lizards, almost half of the 115 species that live in the continental United States. Yet Texas lizards have not received full coverage in regional field guides, and no other guide dedicated solely to the state’s lizards has ever been published. Texas Lizards is a complete identification guide to all fifty-one native and established exotic lizard species. It offers detailed species accounts, range maps, and excellent color photographs (including regional, gender, and age variations for many species) to aid field identification. The authors, two of the state’s most knowledgeable herpetologists, open the book with a broad overview of lizard natural history, conservation biology, observation, and captive maintenance before providing a key to Texas lizards and accounts of the various lizard families and species. Appendices list species of questionable occurrence in Texas and nonestablished exotic species. Informational resources on Texas lizards, a map of Texas counties, a glossary, a bibliography, and indexes of common and scientific names round out the volume.

The Cholistan Desert of Pakistan harbors unique reptile diversity, including ecologically significant agamid lizards of the genera Calotes and Uromastyx , yet their genetic structure remains poorly understood. This study presents the first mitochondrial DNA barcode assessment of these taxa in the region, analyzing 658 bp of the cytochrome c oxidase I ( COI ) gene from 19 specimens collected across seven desert sites. We employed a combination of distance-based (p-distance, K2P) and phylogenetic methods (Maximum Likelihood, Bayesian Inference) to evaluate genetic diversity and evolutionary relationships. Results revealed pronounced divergence between genera (24–30% K2P distance), with Uromastyx populations showing remarkably low intraspecific variation (0–1%), contrasting with higher diversity in Calotes (0–14%). Demographic analyses suggested stable populations (Tajima’s D = 0.93, p > 0.10), though haplotype networks indicated limited gene flow (Nm = 0.12). Our findings: (1) provide the first genetic baseline for these ecologically important desert lizards, (2) identify Uromastyx as potentially more vulnerable to genetic erosion, and (3) demonstrate the utility of COI barcoding for rapid biodiversity assessment in understudied arid ecosystems. The study highlights the Cholistan Desert as an evolutionary significant zone for agamid lizards while underscoring the need for integrated taxonomic approaches to address potential cryptic diversity. All sequence data are publicly available (GenBank PQ896696-PQ896705) to support future conservation genomic studies.

Noninvasive fecal sampling combined with genetic analysis is a technique allowing the study of elusive or otherwise difficult to monitor species without the need for direct contact. Although this method is widely used in birds and mammals, it has never been successfully applied on a large scale in reptiles. The blunt-nosed leopard lizard (Gambelia sila) is an endangered species endemic to the San Joaquin Desert, California, USA. Presently, acquiring data on the species for research and management involves more traditional methods such as live capture or visual surveys, the latter of which are required for regulatory monitoring in accordance with wildlife agency protocols. We used an approach for gathering additional information that combines conservation detection dogs trained to locate blunt-nosed leopard lizard scat samples with genetic analysis for identifying and distinguishing among sympatric lizard species. We developed 2 polymerase chain reaction assays that produce fluorescently labelled amplicons of species-specific fragment length for 6 lizard species in the study area. Using these assays, we genetically identified to species 78% (255 of 327) of samples collected by dog-handler teams across 4 years. The majority of the genetically identified samples (82.4%; 210 of 255) were confirmed as originating from blunt-nosed leopard lizards. Although an assessment of the viability of detection dogs in regulatory monitoring efforts is required, our ability to recover usable DNA and to differentiate among a diverse group of lizards highlights the broad potential of our methodology for noninvasive sampling in reptiles.

Plateau ( Holbrookia lacerata ) and Tamaulipan ( Holbrookia subcaudalis ) spot-tailed earless lizard (STEL) populations have experienced declines in population size and distribution. Both species are considered species of concern and Tamaulipan STEL are being considered for federal threatened status. Even with this heightened concern, little is known about these species. Therefore, our objectives were to determine the most effective and time-efficient methods to survey for STEL, and to determine if a lizard density threshold was required before STEL presence could be detected. We evaluated ten standard reptile search techniques (i.e., pitfall traps, funnel traps, two thermoregulation lures (i.e., rock mounds and cover boards), remote camera surveys, detection dog surveys, quadrant searches, systematic visual searches, environmental DNA sampling, and road cruising) to identify STEL relative abundance within a 1 ha enclosure. The 1 ha enclosure was divided into 100, 10 x 10 m quadrants and each reptile search technique was replicated five times and randomly assigned to a quadrant without replacement. STEL were randomly placed inside the enclosure at known densities of 5, 10, 20, 30, and 40 lizards per ha and their relative abundance was assessed by each method three times at each STEL density during August – September, 2021. STEL were allowed 6-day acclimation periods before increasing density. Because STEL were translocated to novel habitat, caution in interpretation should be noted. However, STEL were not detected using funnel traps, rock mounds, cover boards, remote cameras, and detector dogs at any density level. Pitfall traps, quadrant searches, and eDNA samples detected few STEL, but only at 40 STEL/ha density. Only systematic visual searches and road cruising yielded STEL detections at multiple densities; however, neither method could reliably predict STEL density. Because our detection rates were low (~7% at any STEL density), road cruising can be more time efficient to survey a larger area. Once locations with STEL have been identified, then systematic visual searches between 1300–1500 hr can be conducted to determine the relative abundance of these elusive species.

The Australian skink Egernia stokesii had been recognised as a host of two species of Plasmodium , Plasmodium mackerrasae and P. circularis ; nevertheless, molecular data are available for only a single haemosporidian species of this host. Its sequences are labelled as “ Plasmodium sp.” or “ Plasmodium mackerrasae ”, but morphological characteristics of this isolate are unavailable. Phylogenetic analyses of these sequences placed them into the clade of the genus Haemocystidium . In this study, blood samples of six E. stokesii were analysed by both, molecular and microscopic methods to clarify the haemosporidia of this lizard. Application of these approaches offered discordant results. Whereas sequence analysis clustered our isolates with lizard species of Haemocystidium , morphology of blood stages is more akin to Plasmodium than Haemocystidium . However, limited sampling, indistinguishable nuclei/merozoites and risk of possible hidden presence of mixed infection prevent reliable species identification of detected parasites or their description as new species of Haemocystidium .

Two ways to get legless The evolutionary origins of the Amphisbaenia, a group of legless lizards adapted for burrowing, are controversial. Molecular evidence has placed them within lacertid lizards, whereas morphological evidence tends to unite them with snakes, with inheritance of the limbless, elongate body from a common ancestor. The discovery of a fossil limbed lizard from the famous Eocene Messel shales in Germany should settle the question. The new form seems to combine features of lacertids with those of amphisbaenians, supporting the first hypothesis and suggesting that limblessness in amphisbaenians evolved independently from that in snakes. Amphisbaenia is a speciose clade of fossorial lizards characterized by a snake-like body and a strongly reinforced skull adapted for head-first burrowing 1 , 2 . The evolutionary origins of amphisbaenians are controversial, with molecular data uniting them with lacertids 3 , 4 , a clade of Old World terrestrial lizards, whereas morphology supports a grouping with snakes and other limbless squamates 5 , 6 , 7 , 8 , 9 . Reports of fossil stem amphisbaenians 10 have been falsified 11 , and no fossils have previously tested these competing phylogenetic hypotheses or shed light on ancestral amphisbaenian ecology. Here we report the discovery of a new lacertid-like lizard from the Eocene Messel locality of Germany that provides the first morphological evidence for lacertid–amphisbaenian monophyly on the basis of a reinforced, akinetic skull roof and braincase, supporting the view that body elongation and limblessness in amphisbaenians and snakes evolved independently. Morphometric analysis of body shape and ecology in squamates indicates that the postcranial anatomy of the new taxon is most consistent with opportunistically burrowing habits, which in combination with cranial reinforcement indicates that head-first burrowing evolved before body elongation and may have been a crucial first step in the evolution of amphisbaenian fossoriality.

Conspicuous coloration is an important subject in social communication and animal behavior, and it can provide valuable insight into the role of visual signals in social selection. However, animal coloration can be plastic and affected by abiotic factors such as temperature, making its quantification problematic. In such cases, careful consideration is required so that metric choices are consistent across environments and least sensitive to abiotic factors. A detailed assessment of plastic trait in response to environmental conditions could help identify more robust methods for quantifying color. Temperature affects sexual ornamentation of eastern fence lizards, Sceloporus undulatus, with ventral coloration shifting from green to blue hues as temperatures rise, making the calculation of saturation (color purity) difficult under conditions where temperatures vary. We aimed to characterize how abiotic factors influence phenotypic expression and to identify a metric for quantifying animal color that is either independent from temperature (ideally) or best conserves individual's ranks. We compared the rates of change in saturation across two temperature treatments using seven metrics: three that are based on fixed spectral ranges (with two of them designed by us specifically for this system) and three that track the expressed hue (with one of them designed by us to circumvent spurious results in unornamented individuals). We also applied a lizard visual sensitivity model to understand how temperature-induced color changes may be perceived by conspecifics. We show that the rate of change in saturation between two temperatures is inconsistent across individuals, increasing at a higher rate in individuals with higher baseline saturation at lower temperatures. In addition, the relative color rank of individuals in a population varies with the temperature standardized by the investigator, but more so for some metrics than others. While we were unable to completely eliminate the effect of temperature, current tools for quantifying color allowed us to use spectral data to estimate saturation in a variety of ways and to largely preserve saturation ranks of individuals across temperatures while avoiding erroneous color scores. We describe our approaches and suggest best-practices for quantifying and interpreting color, particularly in cases where color changes in response to environmental factors.

Species inventories are essential for discovering new taxa, improving knowledge of species' geographic distributions, characterizing local richness, evaluating biodiversity loss, and contributing to the conservation of endangered areas, including those with endemic and rare species. The southeastern region of Pará, Brazil, encompasses a transitional zone between the Amazon and Cerrado biomes, marked by a mosaic of natural environments with high variability in relief, substrates, and geological attributes. We conducted a comprehensive survey of the region's herpetofauna, combining taxonomic surveys with molecular characterization, with a particular focus on species associated with savanna-like environments known as canga. We selected four sampling sites: one within the Serra dos Carajás mosaic of protected areas and three in the surrounding region, including São Geraldo do Araguaia, Conceição do Araguaia, and Ourilândia do Norte/São Félix do Xingu. Our inventory recorded a total of 242 species (99 amphibians and 143 squamate reptiles), including ten new records for the state of Pará and two notable range extensions. We also generated a DNA barcode reference library of 860 sequences (436 COI and 424 16S rRNA) from 500 specimens. Approximately 58.4% of amphibian species and 32.2% of squamate reptile species were supported by at least one reference barcode. Our dataset includes five novel COI and two novel 16S rRNA records for amphibians, and 25 novel COI and 13 novel 16S rRNA records for squamate reptiles.

Fossil identification practices have a profound effect on our interpretation of the past because these identifications form the basis for downstream analyses. Therefore, well-supported fossil identifications are necessary for examining the impact of past environmental changes on populations and communities. Here we apply an apomorphic identification framework in a case study identifying fossil lizard remains from Hall’s Cave, a late Quaternary fossil site located in Central Texas, USA. We present images and descriptions of a broad comparative sample of North American lizard cranial elements and compile new and previously reported apomorphic characters for identifying fossil lizards. Our fossil identifications from Hall’s Cave resulted in a minimum of 11 lizard taxa, including five lizard taxa previously unknown from the site. Most of the identified fossil lizard taxa inhabit the area around Hall’s Cave today, but we reinforce the presence of an extirpated species complex of horned lizard. A main goal of this work is to establish a procedure for making well-supported fossil lizard identifications across North America. The data from this study will assist researchers endeavoring to identify fossil lizards, increasing the potential for novel discoveries related to North American lizards and facilitating more holistic views of ancient faunal assemblages.