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Human‐mediated habitat destruction has had a profound impact on increased species extinction rates and population declines worldwide. The coastal development in the United Arab Emirates (UAE) over the last two decades, serves as an example of how habitat transformation can alter the landscape of a country in just a few years. Here, we study the genomic implications of habitat transformation in the Critically Endangered Emirati Leaf‐toed Gecko (Asaccus caudivolvulus), the only endemic vertebrate of the UAE. We generate a high‐quality reference genome for this gecko, representing the first reference genome for the family Phyllodactylidae, and produce whole‐genome resequencing data for 23 specimens from 10 different species of leaf‐toed geckos. Our results show that A. caudivolvulus has consistently lower genetic diversity than any other Arabian species of Asaccus, suggesting a history of ancient population declines. However, high levels of recent inbreeding are recorded among populations in heavily developed areas, with a more than 50% increase in long runs of homozygosity within a 9‐year period. Moreover, results suggest that this species does not effectively purge deleterious mutations, hence making it more vulnerable to future stochastic threats. Overall, results show that A. caudivolvulus is in urgent need of protection, and habitat preservation must be warranted to ensure the species' survival. [ABSTRACT FROM AUTHOR]

Natural history specimens are a widely used and valuable resource for conservation, ecology, and evolutionary biology. One might assume that these collections are representative of natural populations, but recent work has suggested that many collections have disproportionately more male than female specimens. Here, we investigate sex ratios in > 5 000 000 amphibian and reptile specimen records from global natural history collections. We found a slight bias towards males in amphibians (39% females) and reptiles (47% females), but this varied among orders and families. Body size, sexual size dimorphism, and year of collection had little effect. Strikingly however, > 95% of herpetology specimen records had no sex data associated with them at all, even from recent collections. This lack of sex data substantially limits the utility of herpetological museum collections in many ways. We propose that enhanced efforts to train taxonomic specialists and support their careers would unlock the potential of sex-based research using museum collections and their associated public databases. [ABSTRACT FROM AUTHOR]

Effects of anthropogenic activities, including climate change, are modifying fire regimes, and the dynamic nature of these modifications requires identification of general patterns of organisms’ responses to fire. This is a challenging task because of the high complexity of factors involved (including climate, geography, land use, and species‐specific ecology). We aimed to describe the responses of the reptile community to fire across a range of environmental and fire‐history conditions in the western Mediterranean Basin. We sampled 8 sites that spanned 4 Mediterranean countries. We recorded 6064 reptile sightings of 36 species in 1620 transects and modeled 3 community metrics (total number of individuals, species richness, and Shannon diversity) as responses to environmental and fire‐history variables. Reptile community composition was also analyzed. Habitat type (natural vs. afforestation), fire age class (time since the last fire), rainfall, and temperature were important factors in explaining these metrics. The total number of individuals varied according to fire age class, reaching a peak at 15–40 years after the last fire. Species richness and Shannon diversity were more stable during postfire years. The 3 community metrics were higher under postfire conditions than in unburned forest plots. This pattern was particularly prevalent in afforested plots, indicating that the negative effect of fire on reptiles was lower than the negative effect of afforestation. Community composition varied by fire age class, indicating the existence of early‐ and late‐successional species (xeric and saxicolous vs. mesic reptiles, respectively). Species richness was 46% higher in areas with a single fire age class relative to those with a mixture of fire age classes, which indicates pyrodiverse landscapes promoted reptile diversity. An expected shift to more frequent fires will bias fire age distribution toward a predominance of early stages, and this will be harmful to reptile communities. [ABSTRACT FROM AUTHOR]

Thermal and microhabitat resources are two fundamental requirements that affect the life history of any ectotherm. Furthering our understanding of how reptilian species meet these ecological requirements is crucial for assessing the impact of environmental and anthropogenic changes on populations. Here, we explored some fundamental aspects of the thermal and microhabitat ecology of Conopsis biserialis, a small, burrowing, and endemic earthsnake of central Mexico. The study was conducted during the rainy season in a montane site disturbed by rural activities. The mean field body temperature (Tb) of C. biserialis was 26 ± 0.6 ºC. Field Tb did not differ significantly between sex and development stages. However, we found that Tb was positively correlated with substrate, air, and under-rock temperatures (Ts, Ta, and Tr) in the rural microhabitat. Regression analysis showed that substrate and under-rock temperatures (Ts and Tr) were the parameters that best explained Tb variability in the individuals. The temperature and relative humidity under shelter did not differ significantly among shelter types and/or rock sizes. In addition to these thermal traits, earthsnakes selected and utilized six common biotic and physical elements of the rural microhabitat. Most individuals used high proportions of large and medium rocks for sheltering, and these rocks were selected around crop fences and cleared grasslands where the soil can be either covered with low vegetation or bare. Our results suggest that, during the rainy season, individuals of C. biserialis use and select some biotic and structural resources of the rural microhabitats, and were capable of actively regulating their temperature by using shelters with high values of microclimatic homogeneity. [ABSTRACT FROM AUTHOR]

In this study, we investigated the invasiveness of Gekko japonicus, a prevalent gecko species in Japan and an ancient non‐native species, focusing on its competition with both the undescribed endemic Gekko species (referred to as Nishiyamori in Japanese) and G. hokouensis. These species are co‐distributed with G. japonicus, leading us to hypothesize that G. japonicus was invasive upon its initial introduction. We employed niche analysis and population genetics through ddRAD‐seq to assess the historical invasiveness of G. japonicus by comparing regions with and without interspecies competition. Our niche analysis across the Goto Islands, Hiradojima Island (colonized by G. japonicus) and the Koshikishima Islands (not colonized by G. japonicus) indicated that endemic Gekko sp. alter their microhabitat usage in response to invasions by other gecko species, despite having similar suitable habitats and microhabitat preferences. Population genetic analysis revealed significant population declines in Gekko sp. within areas of introduced competition, in contrast to stable populations in areas without such competition. These findings suggest a tripartite competitive relationship among the gecko species, with G. japonicus and G. hokouensis invasions restricting the distribution of the endemic Gekko sp. Consequently, G. japonicus may have historically acted as an invasive species. Acknowledging the historical dynamics of current biodiversity is crucial for addressing complex ecological issues and making informed conservation decisions. [ABSTRACT FROM AUTHOR]

The study of the brain by magnetic resonance imaging (MRI) allows to obtain detailed anatomical images, useful to describe specific encephalic structures and to analyze possible variabilities. It is widely used in clinical practice and is becoming increasingly used in veterinary medicine, even in exotic animals; however, despite its potential, its use in comparative neuroanatomy studies is still incipient. It is a technology that in recent years has significantly improved anatomical resolution, together with the fact that it is non-invasive and allows for systematic comparative analysis. All this makes it particularly interesting and useful in evolutionary neuroscience studies, since it allows for the analysis and comparison of brains of rare or otherwise inaccessible species. In the present study, we have analyzed the prosencephalon of three representative sauropsid species, the turtle Trachemys scripta (order Testudine), the lizard Pogona vitticeps (order Squamata) and the snake Python regius (order Squamata) by MRI. In addition, we used MRI sections to analyze the total brain volume and ventricular system of these species, employing volumetric and chemometric analyses together. The raw MRI data of the sauropsida models analyzed in the present study are available for viewing and downloading and have allowed us to produce an atlas of the forebrain of each of the species analyzed, with the main brain regions. In addition, our volumetric data showed that the three groups presented clear differences in terms of total and ventricular brain volumes, particularly the turtles, which in all cases presented distinctive characteristics compared to the lizards and snakes. [ABSTRACT FROM AUTHOR]

The Middle Jurassic was a critical time in pterosaur evolution, witnessing the appearance of major morphological innovations that underpinned successive radiations by rhamphorhynchids, basally branching monofenestratans, and pterodactyloids. Frustratingly, this interval is particularly sparsely sampled, with a record consisting almost exclusively of isolated fragmentary remains. Here, we describe new material from the Bathonian-aged Kilmaluag Formation of Skye, Scotland, which helps close this gap. Ceoptera evansae (gen. et sp. nov.) is based on a three-dimensionally preserved partial skeleton, which represents one of the only associated Middle Jurassic pterosaurs. Ceoptera is among the first pterosaurs to be fully digitally prepared, and µCT scanning reveals multiple elements of the skeleton that remain fully embedded within the matrix and otherwise inaccessible. It is diagnosed by unique features of the pectoral and pelvic girdle. The inclusion of this new Middle Jurassic pterosaur in a novel phylogenetic analysis of pterosaur interrelationships provides additional support for the existence of the controversial clade Darwinoptera, adding to our knowledge of pterosaur diversity and evolution. [ABSTRACT FROM AUTHOR]

Aim: Global patterns in species distributions such as the latitudinal biodiversity gradient are of great interest to ecologists and have been thoroughly studied. Whether such a gradient holds true for the proportion of species associated with key ecotypes such as forests is however unknown. Identifying a gradient and ascertaining the factors causing it could further our understanding of community sensitivity to deforestation and uncover drivers of habitat specialization. The null hypothesis is that proportions of forest species remain globally consistent, though we hypothesize that proportions will change with differences in ecotype amount, spatial structure, and environmental stability. Here we study whether the proportion of forest species follows a latitudinal gradient, and test hypotheses for why this may occur. Location: Worldwide. Time period: Present. Major taxa studied: Terrestrial vertebrates. Methods: We combined range maps and habitat use data for all terrestrial vertebrates to calculate the proportion of forest species in an area. We then used data on the global distribution of current, recent historical, and long‐term historical forest cover, as well as maps of global disturbances and plant diversity to test our hypotheses using generalized linear models. Results: We identified a latitudinal gradient in the proportion of forest species whereby the highest proportions occurred at the equator and decreased polewards. We additionally found that the proportion of forest species increased with current forest cover, historical deforestation, plant structural complexity, and habitat stability. Despite the inclusion of these variables, the strong latitudinal gradient remained, suggesting additional causes of the gradient. Main conclusions: Our findings suggest that the global distribution of the proportion of forest species is a result of recent ecological, as well as long‐term evolutionary factors. Interestingly, high proportions of forest species were found in areas that experienced historical deforestation, suggesting a lagged response to such perturbations and potential extinction debt. [ABSTRACT FROM AUTHOR]

Deep learning has proven to be highly effective for human activity recognition (HAR) when large amount of labelled data is available for the target task. However, training a deep learning model to generalize well on a new task with just-few observations of labelled data is an active area of research. In this paper, a novel few-shot transfer learning (FSTL) approach is proposed for classification of human activities using just few instances (shots) of the data obtained from a wearable system assembled to collect inertial sensor data for different human activities, performed by two users. First, a deep learning model is trained on a large publicly available HAR dataset. The model parameters of such a model are then fine-tuned using the Reptile algorithm to determine the optimal initial parameter set using which, the model will classify activities with just few-shots of data from the target task. The proposed FSTL approach yields an average classification accuracy of 74.86 ± 0.71% and 79.20 ± 1.05% for 3-way, 5-shot classification of new activities performed by a single user and same set of activities performed by a new user, respectively. When the pre-trained weights are used as the initial weights in the Reptile algorithm, the generalization ability of the model improves by about 10% for 3-way, 5-shot classification as compared to using few-shot learning without parameter transfer. [ABSTRACT FROM AUTHOR]

Simple Summary: Reptiles usually carry Salmonella without showing any signs of infection. In this case, an adult male corn snake died 48 h after eating a feeder mouse bought online. The snake and mouse livers tested positive for Salmonella, specifically Salmonella enterica subsp. enterica serovar Midway. A genome analysis revealed that the two samples were from the same bacterial strain, and both had genes responsible for the bacteria's virulence. This report is about a pet snake that acquired Salmonella from a feeder mouse and then died from septic shock. It shows how feeder mice can be a source of clinical salmonellosis in pet snakes, which can pose a risk to humans too. Reptiles are usually asymptomatic carriers of Salmonella, with the manifestation of typical clinical signs of acute forms in adult and non-immunocompromised animals being considered exceptions. In the present case, an adult male corn snake (Pantherophis guttatus) was found dead due to septic shock 48 h after consuming a feeder mouse purchased online. The snake's tissue samples and faeces were cultured for bacteria isolation. Microbiological examinations of the snake and mouse livers revealed the presence of Salmonella enterica subsp. enterica serovar Midway. A whole-genome analysis of these two isolates showed a high correlation between them: they belonged to the strain type ST-357 for the classic MLST scheme and to the strain type ST 171322 for the cgMLST scheme. Also, a virulence gene analysis revealed the presence of stdB and STM3026 genes. This report conveys a case of food-borne salmonellosis in a pet snake, transmitted from a feeder mouse, likely responsible for the snake's death due to septic shock. It highlights the relevance of feeder mice as a source of Salmonella infections in snakes and the associated risks to human health. [ABSTRACT FROM AUTHOR]

Long-term ecological monitoring is crucial to understanding the complex dynamics of ecosystems, communities, and populations. Despite this, monitoring data are lacking or rare for the vast majority of biodiversity. Here we report the results of 19 years (2003–2022) of continuous annual monitoring of reptile species at Booderee National Park (BNP) on the east coast of south-eastern Australia. We tested the effects of time, habitat type, fire, and climate on detections of five reptile species. Our study revealed declines in detections of two skink species over time (Lampropholis delicata and Ctenotus taeniolatus), which we suspect was partly driven by weather conditions influencing activity of these species. We also identified broad vegetation type associations for two congeneric species with L. delicata being associated with forested sites, and Lampropholis guichenoti associated with more shrubby sites. Our results also demonstrated a clear association between Cryptophis nigrescens and L. delicata and fire, with the probabilities of detection of both species decreasing with time since fire in the short term. At about the midway point of our study (in 2011), we were forced to make a change in the way our data were collected. The change heavily influenced our findings, and so breached the integrity of the time series in our dataset. We acknowledge that a simple but crucial step to mitigate this breach would have been to conduct calibration that allowed subsequent analysis to control for a change in field survey methodology. Whilst improvements in the effectiveness of field survey methods might be possible through new technologies, it is crucial to maintain the integrity of long-term datasets as data collection continues. [ABSTRACT FROM AUTHOR]

Simple Summary: This study uses Maxent models to explore the impact of global climate change on the potential distribution of 5282 reptile species and to estimate their future conservation status. The analysis reveals that over 52.1% of reptile species are experiencing a decrease in their distributional ranges due to global climate change, resulting in a rapid increase in the number of threatened species. However, some reptiles are experiencing an expansion in their potential distribution range under climate change, leading to 91 endangered species being reclassified as least-concern species. Global climate change drives variations in species distribution patterns and affects biodiversity, potentially increasing the risk of species extinction. Investigating the potential distribution range of species under future global climate change is crucial for biodiversity conservation and ecosystem management. In this study, we collected distributional data for 5282 reptile species to assess their conservation status based on distributional ranges using species distribution models. Our predictions indicate that the potential distribution ranges for over half of these species are projected to decrease under different scenarios. Under future scenarios with relatively low carbon emissions, the increase in the number of threatened reptiles is significantly lower, highlighting the importance of human efforts. Surprisingly, we identified some endangered species that are projected to expand their distribution ranges, underscoring the potential positive effects of climate change on some special species. Our findings emphasize the increased extinction risk faced by reptile species due to climate change and highlight the urgent need to mitigate the effects of habitat degradation and human activities on their potential distribution in the future. [ABSTRACT FROM AUTHOR]

Human‐induced environmental change has caused widespread loss of species that support important functions for ecosystems and society. For example, vertebrate scavengers contribute to the functional health of ecosystems and provide services to agricultural landscapes by removing carcasses and associated pests. Widespread extirpation of native Australian mammals since the arrival of Europeans in Australia has removed many scavenging species from landscapes, while scavenging mammals such as European red foxes (Vulpes vulpes) have been introduced. In much of Australia, squamate reptiles are the largest native terrestrial scavengers remaining, where large native mammals are extinct and conservation management is being undertaken to remove invasive mammals. The contribution of reptiles to scavenging functions is not well understood. In this study, we investigated the ecosystem functions provided by large reptiles as scavengers to better understand how populations can be managed to support ecosystem services. We investigated the ecosystem services provided by vertebrate scavengers in Australian coastal mallee ecosystems, focusing on the heath goanna (Varanus rosenbergi), the only extant native terrestrial scavenger in the region. We carried out exclosure experiments, isolating the scavenging activity of different taxonomic groups to quantify the contribution of different taxa to scavenging services, specifically the removal of rat carcasses, and its impact on the occurrence of agriculturally damaging blowflies. We compared areas with different native and invasive scavenger communities to investigate the impact of invasive species removal and native species abundance on scavenging services. Our results indicated that vertebrate scavenging significantly contributes to carcass removal and limitation of necrophagous fly breeding in carcasses and that levels of removal are higher in areas associated with high densities of heath goannas and low densities of invasive mammals. Therefore, augmentation of heath goanna populations represents a promising management strategy to restore and maximize scavenging ecosystem services. [ABSTRACT FROM AUTHOR]

Extensive wildfires can have profound impacts on fauna communities by altering the vegetation structure and resource availability. However, unburnt areas within a fire mosaic may be important habitat for wildlife while the surrounding area recovers after fire. To understand the importance of unburnt vegetation for reptiles, we studied community assemblages at 15 burnt and 15 unburnt sites in a subtropical woodland 12 months after a 25 000 ha wildfire. We tested the relative importance of unburnt areas and structural attributes on reptile abundance, richness, and community composition across this landscape. Unburnt areas had higher species richness and diversity, but not overall abundance. Reptile community composition differed significantly between burnt and unburnt areas. Woody debris, which was retained in unburnt areas but depleted in burnt areas, was positively associated with increased reptile diversity and richness. Our results suggest that unburnt areas are vital for maintaining reptile diversity and richness within a woodland landscape after wildfire. These findings demonstrate the importance of ensuring fire management programs retain unburnt patches of vegetation in fire‐prone landscapes to sustain reptile communities. [ABSTRACT FROM AUTHOR]

The Natura 2000 (N2K) protected area (PA) network is a crucial tool to limit biodiversity loss in Europe. Despite covering 18% of the European Union's (EU) land area, its effectiveness at conserving biodiversity across taxa and biogeographic regions remains uncertain. Testing this effectiveness is, however, difficult because it requires considering the nonrandom location of PAs, and many possible confounding factors. We used propensity score matching and accounted for the confounding effects of biogeographic regions, terrain ruggedness, and land cover to assess the effectiveness of N2K PAs on the distribution of 1769 species of conservation priority in the EU's Birds and Habitats Directives, including mammals, birds, amphibians, reptiles, arthropods, fishes, mollusks, and vascular and nonvascular plants. We compared alpha, beta, and gamma diversity between matched selections of protected and unprotected areas across EU's biogeographic regions with generalized linear models, generalized mixed models, and nonparametric tests for paired samples, respectively, for each taxonomic group and for the entire set of species. PAs in N2K hosted significantly more priority species than unprotected land, but this difference was not consistent across biogeographic regions or taxa. Total alpha diversity and alpha diversity of amphibians, arthropods, birds, mammals, and vascular plants were significantly higher inside PAs than outside, except in the Boreal biogeographical region. Beta diversity was in general significantly higher inside N2K PAs than outside. Similarly, gamma diversity had the highest values inside PAs, with some exceptions in Boreal and Atlantic regions. The planned expansion of the N2K network, as dictated by the European Biodiversity Strategy for 2030, should therefore target areas in the southern part of the Boreal region where species diversity of amphibians, arthropods, birds, mammals, and vascular plants is high and species are currently underrepresented in N2K. [ABSTRACT FROM AUTHOR]

Barn owls are the most widely distributed group of owls in the world and are among the most common accumulators of small vertebrate remains at archeological and paleontological sites. Despite its importance as a bone remains accumulator and predictor of paleoenvironmental conditions due to its generalist habits, the vertebrate prey of this raptor has been scarcely studied from an ecological community perspective, especially considering the diverse range of prey it captures. Archeological, paleontological, and taphonomic studies typically reveal taxon-specific patterns, focusing primarily on small rodents. In order to overcome this problem, we studied an assemblage of vertebrate bones from barn owl pellets in the central Monte Desert of Argentina. Our analysis included the full range of prey taxa, including rodents, marsupials, birds, and reptiles, addressed from both an ecological and neo-taphonomic perspective. We compare the taxonomic and taphonomic findings with those from regional small vertebrate records obtained from various sampling types over the past 50 years to explore recent environmental changes within the Anthropocene. The assemblage of small vertebrate prey presented here comprises five species of cricetids, one species from the Caviidae family, and at least one ctenomyid rodent species. Additionally, the assemblage includes one species of didelphid marsupial, one reptile species, and at least six passeriform bird species that belong to separate families. The overall taphonomic trends are consistent with the typical barn owl pattern. However, our analysis identified a larger percentage of postcranial elements exhibiting signs of digestion compared to pellet-derived vertebrate bone assemblages previously documented. Furthermore, it is important to note that a significant proportion of avian bone fragments exhibit distinct signs of digestion. [ABSTRACT FROM AUTHOR]

Simple Summary: Chromosome changes represent important events in evolution. They may trigger processes of speciation or be the result of phylogenetic diversification. In both cases they can represent discrete evolutionary markers of taxonomic significance. In this contribution, we performed a comparative cytogenetic analysis on several representatives of the Malagasy ground geckos of the genus Paroedura. Our results show that chromosome variability in this genus involves chromosome number, morphology, and the independent differentiation of sex chromosome systems in distinct evolutionary lineages. We also highlight that the taxonomic, genetic and chromosome diversity in Paroedura is still underestimated. We present a comparative chromosome study of several taxa of the Malagasy ground geckos of the Paroedura bastardi and P. picta species groups. We employed a preliminary molecular analysis using a trait of the mitochondrial 16S rRNA gene (of about 570 bp) to assess the taxonomic status of the samples studied and a cytogenetic analysis with standard karyotyping (5% Giemsa solution), silver staining (Ag–NOR staining) and sequential C-banding (C-banding + Giemsa and + fluorochromes). Our results show that all the taxa studied of the P. bastardi group (P. ibityensis, P. rennerae and P. cf. guibeae) have a similar karyotype composed of 2n = 34 chromosomes, with two metacentric pairs (1 and 3) and all other pairs being acrocentric. Chromosome diversification in the P. bastardi group was mainly linked to the diversification of heteromorphic sex chromosome systems (ZZ/ZW) in P. ibityensis and P. rennerae, while no heteromorphic sex chromosome pair was found in P. cf. guibeae. The two taxa investigated of the P. picta species group (here named P. picta and P. cf. picta based on molecular data) showed the same chromosome number of 2n = 36, mostly acrocentric elements, but differed in the number of metacentric elements, probably as a result of an inversion at chromosome pair 2. We highlight that the genus Paroedura is characterized by the independent diversification of heterogametic sex chromosomes in different evolutionary lineages and, similarly to other phylogenetically related gecko genera, by a progressive formation of a biarmed element by means of tandem fusions and inversions of distinct pairs. [ABSTRACT FROM AUTHOR]

This document is a compilation of peer-reviewed publications from July to December 2023 on infectious agents of reptiles and amphibians. The articles cover a range of topics, including viruses, bacteria, and their impact on various species. Some notable findings include the molecular characterization of a reptarenavirus in a Colombian red-tailed boa, the detection of ranavirus in common musk turtles, and the prevalence and genetic diversity of ranavirus in Asia. Additionally, there are articles on amphibian dermatology, the gut microbiota's role in ranavirus infection, and the correlation between microbial communities and hatching failure in loggerhead sea turtles. [Extracted from the article]

The prevalence of environmental sex determination (ESD) in squamate reptiles is often overestimated in the literature. This is surprising because we have reliable data demonstrating ESD in only a few species. The documentation of ESD in three species of geckos presented here has significantly increased our knowledge, given that satisfactory evidence for ESD existed in only eight other gecko species. For the first time, we document the occurrence of ESD in the family Sphaerodactylidae. Our finding of unexpected variability in the shapes of reaction norms among geckos highlights that traditional descriptions using parameters such as pivotal temperature, that is, temperature producing a 50:50 sex ratio, are unsatisfactory. For example, the gecko Pachydactylus tigrinus lacks any pivotal temperature and its sex ratios are strongly female‐biased across the entire range of viable temperatures. We argue for the effective capture of the relationship between temperature and sex ratio using specific nonlinear models rather than using classical simplistic descriptions and classifications of reaction norms. Research highlights: Variability in norms of reaction of environmental sex determination (ESD) among three species of geckos is documented. In Pachydactylus tigrinus, highly female‐biased sex ratios were found across all temperatures. [ABSTRACT FROM AUTHOR]

Organisms whose early life stages are environmentally sensitive produce offspring within a relatively narrow range of suitable abiotic conditions. In reptiles, development rate and survival are often maximized if incubation temperatures remain under 31°C, though this upper bound may vary within and among species. We addressed this expectation by comparing responses to egg incubation at 30°C versus 33°C in congeneric turtle species pairs with broad syntopic geographic distributions. In the two softshell turtles (Apalone spp.), the greatest changes in development rate and phenotypic variance were observed in the northernmost population, which had a low survival rate (40%) at 33°C. The presumably suboptimal temperature (33°C) for northern populations otherwise yielded 76%–93% survival rates and fast swimming speeds in more southern populations. Still, in one species, northern hatchlings incubated at 33°C matched the elevated speeds of their southern counterparts, revealing a countergradient response. In northern populations of the two map turtles (Graptemys spp.), survival was also reduced (28%–60%) at 33°C and the development rate (relative to 30°C) increased by up to 75%. Our experiments on divergent taxa with similar nesting ecologies substantiate that the optimal thermal range for offspring production is variable. These findings encourage further work on how population‐ and species‐level differences relate to local adaptation in widely distributed oviparous species. Research highlights: Geographic variation was evaluated in turtles.High egg incubation temperatures reduced offspring survival in the north, with a countergradient response in some populations.The optimal thermal regimes likely differ according to trait and population. [ABSTRACT FROM AUTHOR]

Emerging and re‐emerging pathogens often stem from zoonotic origins, cycling between humans and animals, and are frequently vectored and maintained by hematophagous arthropod vectors. The efficiency by which these disease agents are successfully transmitted between vertebrate hosts is influenced by many factors, including the host on which a vector feeds. The Lyme disease bacterium Borrelia burgdorferi sensu lato has adapted to survive in complex host environments, vectored by Ixodes ticks, and maintained in multiple vertebrate hosts. The versatility of Lyme borreliae in disparate host milieus is a compelling platform to investigate mechanisms dictating pathogen transmission through complex networks of vertebrates and ticks. Squamata, one of the most diverse clade of extant reptiles, is comprised primarily of lizards, many of which are readily fed upon by Ixodes ticks. Yet, lizards are one of the least studied taxa at risk of contributing to the transmission and life cycle maintenance of Lyme borreliae. In this review, we summarize the current evidence, spanning from field surveillance to laboratory infection studies, supporting their contributions to Lyme borreliae circulation. We also summarize the current understanding of divergent lizard immune responses that may explain the underlying molecular mechanisms to confer Lyme spirochete survival in vertebrate hosts. This review offers a critical perspective on potential enzootic cycles existing between lizard‐tick‐Borrelia interactions and highlights the importance of an eco‐immunology lens for zoonotic pathogen transmission studies. [ABSTRACT FROM AUTHOR]

Context: Annual patterns in behaviour and demography define longer-term changes in reptile populations, probability of species detection and risks of local extinction. Aims: To determine seasonal activity and demographic parameters of species in an isolated assemblage adapted to a seasonally predictable climate. Methods: A 37-year pitfall trapping, capture–release study in a 338-ha inner-city bushland experiencing a Mediterranean climate. Pit trap methodology changed after 7 years. Results: Reproductive activity of 29 species peaked during austral spring to early summer with hatching or births occurring from late summer to early autumn. Growth, as determined from size changes over demi-monthly periods, indicated sexual maturity varied from <1 year to 5 years. Five of eight uniquely marked species had longevity exceeding a decade while individuals within six species moved over a kilometre. Dimorphism in adult length and mass was significantly greater in females for 15 of the 18 species with adequate data. Adult male activity peaked earlier in spring than adult females' over the latter 30 years; hatchlings had different species-specific activity and annual cohort survival patterns. Activity declined in adults through summer and autumn before brumation in late autumn and winter in all species and age-size categories. Capture frequency in most species changed between methodologies. Conclusions: Species had broadly similar seasonal activity but different demographic parameters within an isolated reptile assemblage currently experiencing increasing temperature and declining rainfall. Implications: Comprehending seasonal variation is essential for interpreting decadal-long changes in reptile numbers experiencing a drying climate that alters activity, reproduction and survival to inform species detectability and likely extinction risk. South-western Australia's species are adapted to a predictable climate that is now experiencing increasing temperatures and declining rainfall. Population parameters for most of 29 reptile species, evaluated in situ , are documented to assist in interpreting species performance and predicting persistence under ongoing habitat modification and a varying climate. [ABSTRACT FROM AUTHOR]

Solute carrier family 26 (Slc26) is a family of anion exchangers with 11 members in mammals (named Slc26a1‐a11). Here, we identified a novel member of the slc26 family, slc26a12, located in tandem with slc26a2 in the genomes of several vertebrate lineages. BLAST and synteny analyses of various jawed vertebrate genome databases revealed that slc26a12 is present in coelacanths, amphibians, reptiles, and birds but not in cartilaginous fishes, lungfish, mammals, or ray‐finned fishes. In some avian and reptilian lineages such as owls, penguins, egrets, and ducks, and most turtles examined, slc26a12 was lost or pseudogenized. Phylogenetic analysis showed that Slc26a12 formed an independent branch with the other Slc26 members and Slc26a12, Slc26a1 and Slc26a2 formed a single branch, suggesting that these three members formed a subfamily in Slc26. In jawless fish, hagfish have two genes homologous to slc26a2 and slc26a12, whereas lamprey has a single gene homologous to slc26a2. African clawed frogs express slc26a12 in larval gills, skin, and fins. These results show that slc26a12 was present at least before the separation of lobe‐finned fish and tetrapods; the name slc26a12 is appropriate because the gene duplication occurred in the distant past. [ABSTRACT FROM AUTHOR]

Background: Snakebite envenomation inflicts a high burden of mortality and morbidity in sub-Saharan Africa. Antivenoms are the mainstay in the therapy of envenomation, and there is an urgent need to develop antivenoms of broad neutralizing efficacy for this region. The venoms used as immunogens to manufacture snake antivenoms are normally selected considering their medical importance and availability. Additionally, their ability to induce antibody responses with high neutralizing capability should be considered, an issue that involves the immunization scheme and the animal species being immunized. Methodology/Principal findings: Using the lethality neutralization assay in mice, we compared the intrageneric neutralization scope of antisera generated by immunization of horses with monospecific, bispecific/monogeneric, and polyspecific/monogeneric immunogens formulated with venoms of Bitis spp., Echis spp., Dendroaspis spp., spitting Naja spp. or non-spitting Naja spp. It was found that the antisera raised by all the immunogens were able to neutralize the homologous venoms and, with a single exception, the heterologous congeneric venoms (considering spitting and non-spitting Naja separately). In general, the polyspecific antisera of Bitis spp, Echis spp, and Dendroaspis spp gave the best neutralization profile against venoms of these genera. For spitting Naja venoms, there were no significant differences in the neutralizing ability between monospecific, bispecific and polyspecific antisera. A similar result was obtained in the case of non-spitting Naja venoms, except that polyspecific antiserum was more effective against the venoms of N. melanoleuca and N. nivea as compared to the monospecific antiserum. Conclusions/Significance: The use of polyspecific immunogens is the best alternative to produce monogeneric antivenoms with wide neutralizing coverage against venoms of sub-Saharan African snakes of the Bitis, Echis, Naja (non-spitting) and Dendroaspis genera. On the other hand, a monospecific immunogen composed of venom of Naja nigricollis is suitable to produce a monogeneric antivenom with wide neutralizing coverage against venoms of spitting Naja spp. These findings can be used in the design of antivenoms of wide neutralizing scope for sub-Saharan Africa. Author summary: Parenteral administration of antivenoms is the core of the current treatment of snakebite envenomations, and there is an urgent need to produce antivenoms of wide neutralizing efficacy for sub-Saharan Africa. The active substance of antivenoms are antibodies (or antibody fragments) purified from plasma of horses or sheep immunized by the repeated injection of snake venoms. Generally, these antibodies can neutralize the venoms used as immunogens and other related venoms. Normally, the venoms used as immunogens are selected considering their medical importance and availability. To complement these criteria with information regarding the immunogenicity of venoms, we compared monospecific, bispecific/monogeneric, and polyspecific/monogeneric antisera towards venoms of Bitis spp., Echis spp., Dendroaspis spp., spitting Naja spp. or non-spitting Naja spp, regarding their intrageneric neutralization scope, evaluated by the lethality neutralization assay in mice. We found that the polyspecific antisera against venoms of Bitis spp, Echis spp, Dendroaspis spp, or non-spitting Naja gave the best neutralization profile. On the other hand, the monospecific, bispecific and polyspecific antisera towards venoms of spitting Naja venoms showed a similar performance. This information suggests that polyspecific immunogens could be the best alternative to produce antivenoms with the widest neutralizing coverage against sub-Saharan African snake venoms. [ABSTRACT FROM AUTHOR]

Nuclear speckles are compartments enriched in splicing factors present in the nucleoplasm of eucaryote cells. Speckles have been studied in mammalian culture and tissue cells, as well as in some non-mammalian vertebrate cells and invertebrate oocytes. In mammals, their morphology is linked to the transcriptional and splicing activities of the cell through a recruitment mechanism. In rats, speckle morphology depends on the hormonal cycle. In the present work, we explore whether a similar situation is also present in non-mammalian cells during the reproductive cycle. We studied the speckled pattern in several tissues of a viviparous reptile, the lizard Sceloporus torquatus, during two different stages of reproduction. We used immunofluorescence staining against splicing factors in hepatocytes and oviduct epithelium cells and fluorescence and confocal microscopy, as well as ultrastructural immunolocalization and EDTA contrast in Transmission Electron Microscopy. The distribution of splicing factors in the nucleoplasm of oviductal cells and hepatocytes coincides with the nuclear-speckled pattern described in mammals. Ultrastructurally, those cell types display Interchromatin Granule Clusters and Perichromatin Fibers. In addition, the morphology of speckles varies in oviduct cells at the two stages of the reproductive cycle analyzed, paralleling the phenomenon observed in the rat. The results show that the morphology of speckles in reptile cells depends upon the reproductive stage as it occurs in mammals. [ABSTRACT FROM AUTHOR]

The small diapsid reptile Ozimek volans is one of the most enigmatic representatives of the Late Triassic fauna of Krasiejów, Poland. Phylogenetically, Ozimek was identified as a 'protorosaurian' related to tanystropheids, but the extremely elongated limbs and presumed gliding abilities are unusual for this group. This raises the question of whether the lifestyle inferred for this taxon is reflected in its bone histology. Two long bones from a single bone association of Ozimek (humerus UOPB 1148a and femur UOPB 1148b) were sectioned at the midshaft to obtain details of the histological framework. A large medullary cavity, thin walls of lamellar bone with numerous lamellae, and only very few simple vascular canals are shared by both bones. Application of a modified 3‐front model (introducing a fourth front) of cortical growth reveals that the femur is ontogenetically younger when compared to the humerus. Ozimek limb bones, with their small diameter, compact structure, low vascularization, no remodelling, and a lack of pneumaticity, are histologically similar to those of modern small bats. The characteristic cortex of both may have been well suited to withstand high loads while limiting weight. The well‐ordered collagen fibres in successive lamellae along the bone may be a key adaptation for the better distribution of the load generated during gliding. © 2024 The Palaeontological Association. [ABSTRACT FROM AUTHOR]

Temperate reptiles are often considered to be low-energy systems, with their discrete use of time and energy making them model systems for the study of time-energy budgets. However, the semifrequent replacement and sloughing of the epidermis is a ubiquitous feature of squamate reptiles that is often overlooked when accounting for time and energy budgets in these animals. We used open-flow respirometry to measure both the energetic effort of ecdysis and the duration of the associated metabolic upregulation (likely related to behavioral changes often reported for animals in shed) in wild-caught timber rattlesnakes (Crotalus horridus). We hypothesized that total effort of skin biosynthesis and physical removal would be related to body mass and expected the duration of the process to remain static across individuals at a fixed temperature (25°C). We provide both the first measurements of the cost of skin biosynthesis and physical removal in a reptile and the highest-resolution estimate of process duration recorded to date. We found that skin biosynthesis, but not the cost of physical removal of the epidermis, was related to body mass. Shed cycle duration was consistent across individuals, taking nearly 4 wk from process initiation to physical removal of the outermost epidermal layer. Total energetic effort of ecdysis was of sizeable magnitude, requiring ∼3% of the total annual energy budget of a timber rattlesnake. Energetic effort for a 500-g snake was equivalent to the amount of metabolizable energy acquired from the consumption of approximately two adult mice. Ecdysis is a significant part of the time-energy budgets of snakes, necessitating further attention in studies of reptilian energetics. [ABSTRACT FROM AUTHOR]

The blind snake Helminthophis flavoterminatus (Peters, 1857) is a species of Anomalepididae with distribution throughout northwestern Venezuela and western Colombia. Its osteology is poorly known, and thus this study presents information on its skull structure based on High-Resolution X-Ray Computed Tomography. The absence of the supraoccipital bone can be used for the determination of H. flavoterminatus in relation to its congeners, Helminthophis frontalis (Peters, 1860) and Helminthophis praeocularis Amaral, 1924. [ABSTRACT FROM AUTHOR]

Age‐related telomere length (TL) variation is relatively well‐described for mammals, birds and other model organisms. Nevertheless, it remains largely unknown in ectotherms, especially turtles and tortoises, which are extremely long‐lived species with slow or negligible senescence. In this study, we described TL dynamics in wild spur‐thighed tortoises (Testudo graeca), one of the chelonian species with the lowest aging rates. By combining cross‐sectional (single) and longitudinal (capture–recapture) samplings, we assessed the relationship between TL and individual characteristics (sex, age, individual growth rate, body condition index, presence of shell anomalies). We did not find any association between TL and sex, individual growth rate, or body condition. However, the relationship with age remains uncertain, likely due to the complex dynamics of TL over time. Interestingly, shorter telomeres correlated significantly with shell anomalies, which are usually assumed as a fitness proxy for reptiles. Overall, our results suggest TL as a potential indicator for ontogenetic studies on tortoises, while its utility as a marker of biological age appears limited. [ABSTRACT FROM AUTHOR]

The genus Hepatozoon Miller (1908) contains a wide range of obligate parasitic organisms with complex life cycles involving vertebrates and hematophagous invertebrates. Despite over 300 species being described, only a small percentage has been characterized in snakes using morphological and molecular techniques. The prevalence of these parasites in snakes is significant, highlighting the need for molecular descriptions in such elusive hosts. Thus, the objective of this study was to determine molecularly the presence of Hepatozoon species in snakes from the Northeastern region of Argentina. Thirty-two specimens of eight snake species (Bothrops alternatus, Dryophylax hypoconia, Erythrolamprus jaegeri coralliventris, Erythrolamprus poecilogyrus, Erythrolamprus semiaureus, Philodryas olfersii latirostris, Pseudablabes (ex Philodryas) patagoniensis and Palusophis (ex Mastigodryas) bifossatus were collected and examined. PCR analysis of the 18S rRNA locus detected four samples (12% prevalence) positive for the presence of Hepatozoon DNA. Phylogenetic analysis positioned the 18S rRNA Hepatozoon sequences obtained in three different clades, one with Hepatozoon musa, another with sequences of Hepatozoon cuestensis, while the third was placed as a sister taxon to a clade including Hepatozoon cevapii and Hepatozoon massardi. This study presents the first documentation of Hepatozoon infecting snakes in Argentina, thereby expanding their distribution within southern South America. Additionally, B. alternatus and Pa. bifossatus are reported as new hosts of Hepatozoon. [ABSTRACT FROM AUTHOR]

Reptiles are known to be asymptomatic carriers of various zoonotic pathogens. A number of Gram-negative opportunistic commensals are causative agents of bacterial infections in immunocompromised or stressed hosts and are disseminated by reptiles, whose epidemiological role should not be neglected. Since most studies have focused on exotic species, in captivity or as pet animals, the role of wild populations as a potential source of pathogens still remains understudied. In the present study, we isolated a variety of Gram-negative bacteria from the cloacal microbiota of free-living lizard and tortoise hosts (Reptilia: Sauria and Testudines) from the Bulgarian herpetofauna. We evaluated their pathogenic potential according to their antibiotic susceptibility patterns, biofilm-forming capacity, and extracellular production of some enzymes considered to play roles as virulence factors. To our knowledge, the phenotypic manifestation of virulence factors/enzymatic activity and biofilm formation in wild reptile microbiota has not yet been widely investigated. All isolates were found to be capable of forming biofilms to some extent and 29.6% of them could be categorized as strong producers. Two strains proved to be excellent producers. The majority of the isolated strains showed extracellular production of at least one exoenzyme. The most pronounced pathogenicity could be attributed to the newly isolated Pseudomonas aeruginosa strain due to its multiresistance, excellent biofilm formation, and expression of exoenzymes. [ABSTRACT FROM AUTHOR]

Simple Summary: The expansion of human activities into natural areas increases contact between humans, domestic animals, and wildlife, which can facilitate the circulation of infectious agents between these species, leading to the emergence of zoonoses. Several studies have investigated the role of animals, including reptiles, as possible carriers of the Leptospira bacterium. This study aimed to detect the DNA of the bacterium in Kinosternon scorpioides turtles kept in captivity in a region of the Brazilian Amazon. Blood, cloacal fluid, cloacal lavage, and stomach lavage samples were collected from 40 turtles. Of these, 40% of the animals tested positive for Leptospira. Genetic analysis confirmed the identification of the bacteria, which could pose a risk to public health. Handling infected animals could increase the risk of transmitting the disease, especially considering that turtle meat is consumed in the region. This study is the first to detect Leptospira in the blood of chelonians, confirming exposure to the pathogen. Although the turtles showed no abnormal clinical signs, it is possible that the clinical signs are unknown in reptiles. In conclusion, captive K. scorpioides turtles have been exposed to Leptospira. Leptospirosis is a zoonosis of great importance for One Health. In this context, the Amazonian biome may harbor numerous hosts for Leptospira spp. that contribute to the maintenance of the pathogen in the environment. Some reptiles, such as chelonians, have been little studied in terms of their involvement with leptospires. The objective of this study was to detect Leptospira spp. DNA in Kinosternon scorpioides turtles kept in captivity in a region of the Brazilian Amazon. A total of 147 samples of blood (n = 40), cloacal fluid (n = 27), cloacal lavage (n = 40), and stomach (n = 40) were collected from 40 chelonians. After DNA extraction, the samples were subjected to amplification of a 331 base pair product of the 16S rRNA gene using the Lep1 and Lep2 primers. PCR products were Sanger sequenced, assembled, and subjected to online blast search and phylogenetic analysis. Of the animals tested, 40% (16/40, 95% confidence interval [CI]: 25–55) had at least one or two samples positive for Leptospira spp. Considering the total number of samples collected, 12.93% (19/147) were positive, being blood clots (27.5%; 11/40), followed by cloacal washings (10%; 4/40), cloacal fluid (11.11%; 3/27) and gastric washings (2.5%; 1/40). Of these, 11 samples were sequenced and showed 99% to 100% identity with Leptospira interrogans sequences, which was confirmed by phylogenetic analysis. This is the first study to detect pathogenic Leptospira DNA in chelonians in a region of the Brazilian Amazon. It has been concluded that K. scorpioides turtles in captivity have been exposed to pathogenic Leptospira. [ABSTRACT FROM AUTHOR]

OBJECTIVE To evaluate and compare the pharmacokinetic parameters of SC ceftazidime administered at 20 and 40 mg/kg to red-eared sliders. ANIMALS 8 adult red-eared sliders (Trachemys scripta elegans). METHODS In a sequential, 2-period study with a 3-week washout period between treatments, ceftazidime was administered SC to turtles at 20 and 40 mg/kg. Blood samples were collected from the subcarapacial sinus at 0, 24, 48, 72, 96, and 120 hours after ceftazidime administration. Plasma ceftazidime concentrations were quantified using reversedphase HPLC. RESULTS Mean plasma half-life after 20- and 40-mg/kg dosing was 39.75 ± 8.0 hours and 33.03 ± 6.56 hours, respectively. Mean maximum plasma concentration after 20- and 40-mg/kg dosing was 71.0 ± 15.93 µg/mL and 120.0 ± 30.62 µg/mL, respectively. Mean plasma ceftazidime concentrations remained ≥ 8 µg/mL, the theoretical MIC for various reptile pathogens for all time points. CLINICAL RELEVANCE Results indicate that ceftazidime dosed at either 20 or 40 mg/kg produces plasma concentrations exceeding the theoretical MIC of various reptile pathogens for at least 120 hours. An ideal dosing interval could not be determined, as all plasma concentrations remained above the threshold of interest for all time points. Follow-up studies should focus on establishing a dosing interval and more rigorous monitoring for potential adverse effects. [ABSTRACT FROM AUTHOR]

Alpine ecosystems harbour a rich and highly specialised biodiversity, which is particularly susceptible to anthropogenic disturbances such as habitat loss and fragmentation as well as to climate change. Combined with other forms of land‐use conversion, construction and maintenance of ski resorts can have severe consequences on alpine biodiversity. In this study, we show how one amphibian and two reptile species, namely Rana temporaria, Zootoca vivipara and Vipera berus, respond to such impacts by means of a multi‐season occupancy analysis. We found all three species both in and outside ski‐runs, showing that these habitats do not necessarily preclude their occurrence. Contrarily, this is influenced more by microhabitat availability, such as ground vegetation, humid areas and rock cover, rather than by macro‐characteristics like elevation or habitat type. Moreover, we found a climatic influence on the year‐to‐year occupancy change of the species, with activity‐month conditions being more relevant than overwintering ones. Our results demonstrate how, in the specific case of reptiles and amphibians, ski resorts do not necessarily limit species' occurrence and that a mild series of management actions might secure the species' persistence in the area. [ABSTRACT FROM AUTHOR]

Knowledge of the spatial distribution of reptiles is essential for decision-making in conservation under future climate change scenarios. We present a new compilation of reptile records for Odesa Oblast (i.e. province), south-west Ukraine. We compiled 662 records: 200 from our own research during 2012–2022, 362 from the published literature, 73 from public databases and 27 from museum collections. Fourteen native species of reptile (one species of Emydidae, four of Lacertidae, one of Anguidae, six of Colubridae and two of Viperidae) have been recorded in Odesa Oblast but the distribution of several are poorly known and/or records have rarely been published. We also report four introduced reptile species (one each of Emydidae, Gekkonidae, Lacertidae and Anguidae). We present the data in a grid of 462 10 × 10 km cells covering the oblast. In this compilation we did not record any new species, but our records include previously unreported localities for some species. Species richness was highest in the areas along the Black Sea, in protected areas. The main threats to the reptiles in Odesa Oblast are the alteration and degradation of habitats, military action, uncontrolled pressure from infrastructure projects and the presence of invasive species. [ABSTRACT FROM AUTHOR]

Our knowledge of marine reptiles of the Callovian age (Middle Jurassic) is majorly based on the collections from the Oxford Clay Formation of England, which yielded a diverse marine reptile fauna of plesiosaurians, ichthyosaurians, and thalattosuchians. However, outside of Western Europe, marine reptile remains of this age are poorly known. Here, we survey marine reptiles from the Callovian stage of European Russia. The fossils collected over more than a century from 28 localities are largely represented by isolated bones and teeth, although partial skeletons are also known. In addition to the previously described rhomaleosaurid and metriorhynchids, we identify pliosaurids of the genera Liopleurodon and Simolestes; cryptoclidid plesiosaurians, including Cryptoclidus eurymerus, Muraenosaurus sp., and cf. Tricleidus, and ophthalmosaurid ichthyosaurians, including the iconic Ophthalmosaurus icenicus. These findings expand the ranges of several Callovian marine reptile taxa far to the Eastern Europe, and support the exchange of marine reptile faunas between Western and Eastern European seas in the middle to late Callovian. However, some specimens from the lower Callovian of European Russia show differences from typical representatives of the middle Callovian Oxford Clay fauna, possibly representing the earlier stages of evolution of some of these marine reptiles not yet recorded in Western Europe or elsewhere. [ABSTRACT FROM AUTHOR]

Climate and land use changes are eroding biodiversity globally, and reptiles are highlighted as being particularly susceptible. In South Africa, global changes threaten the persistence of an assemblage of dwarf chameleons (Bradypodion) located in a biodiversity hotspot. We used ecological niche modelling to assess the combined effect of climate change and habitat transformation on these species and assessed their susceptibility in a vulnerability framework under optimistic and pessimistic change scenarios. Although our models showed a gain in suitable climatic space for all coastal species in some scenarios, considerable losses were predicted for most species under the most pessimistic change scenarios. Bradypodion ngomeense, for example is predicted to incur a complete loss of climatic suitability by 2050. The vulnerability framework predicts inland species to be more adversely affected by climate change than coastal species. However, no species show resilience to the combined effects of climate change and habitat transformation. Our models predicted a loss of climatically suitable habitat for most species in protected areas. These findings highlight the importance of a protected area network design to remain a step ahead of these anticipated changes. [ABSTRACT FROM AUTHOR]

Color and pattern are often critical to survival and fitness, but we know little about their genetic architecture and heritability in groups like reptiles. We investigated the genetic architecture for the pattern of the dewlap—an extensible throat fan important for communication—in anole lizards. We studied the Hispaniolan bark anole (Anolis distichu s)—a species that exhibits impressive intraspecific dewlap polymorphism across its range—by conducting multigenerational experimental crosses with 2 populations, one with a solid pale yellow dewlap and another with an orange dewlap surrounded by a yellow margin. Upon rejecting the hypothesis that the extent of the orange pattern is a quantitative trait resulting from many loci of minor effect, we used a maximum likelihood model-fitting framework to show that it is better explained as a simple Mendelian trait, with the solid yellow morph being dominant over the blush orange. The relatively simple genetic architecture underlying this important trait helps explain the complex distribution of dewlap color variation across the range of A. distichus and suggests that changes in dewlap color and pattern may evolve rapidly in response to natural selection. [ABSTRACT FROM AUTHOR]

Palacrodon, a near-crown stem reptile, is known from several Triassic sites across the globe, and is easily recognized by its dentition characterized by labiolingually expanded molariform teeth coupled with acrodont tooth implantation. Here we explore the nature of tooth implantation and attachment in specimens of Palacrodon from South Africa and Arizona, U.S.A. using µCT. We note the presence of unusual ridges located underneath the tooth crowns in Palacrodon browni. Such ridges are not present in specimens from Arizona, which warrants the naming of a new species P. parkeri. We conducted a broad survey of internal tooth morphology across extant and extinct pan-reptiles (n = 212), and we conclude that homologous ridges like those we observe in P. browni are not present in any other species of reptile. As such, our ability to determine the function of the ridges is limited, though we hypothesize it is related to tooth attachment via unmineralized soft tissues. [ABSTRACT FROM AUTHOR]

Around the middle of the nineteenth century, Italian palaeontologists began to investigate fossils of fishes and reptiles from the Middle Triassic outcrops in the vicinity of Monte San Giorgio (Canton Ticino, Switzerland). In 1924, researchers from the University of Zurich started their scientific excavations on the Swiss side. The many fish fossils found since then have often stood in the shadow of the more spectacular and mostly larger fossils of various aquatic reptiles. Beginning around 1980 the fish fossils in the collection of the Palaeontological Institute and Museum of Zurich University have subsequently been brought out of this shadow. The picture presently emerging is that of a species rich fish fauna located in six different fossiliferous beds of Anisian and Ladinian age with a few chondrichthyan, some coelacanth and a wealth of different actinopterygian taxa, many of them well preserved. The ongoing work not only results in taxonomic and systematic novelties, but gives also new insights into their palaeobiology, palaeoecology and palaeobiogeography. [ABSTRACT FROM AUTHOR]

Clinical assessment of body condition is crucial in captive and free-ranging reptiles, since a large percentage of diseases result from inadequate nutrition. However, preventive health care is restricted by the lack of a practical method for the assessment in tortoises. Pre-existing evaluation systems based on weight and shell measurements are laborious and ignore the clinical presentation of the animal. The present study aimed to facilitate the assessment by establishing a body condition score. A total of 373 Hermann's Tortoises (Testudo hermanni) (n = 281 tortoises kept as pets in Germany and n = 92 tortoises originating from a free-ranging population (68) or a rearing station (24) in France) were examined and data (weight (g), carapace length (cm), width (cm), height (cm)) were recorded in a standard protocol between October 2020 and October 2021. A modified version of a body condition score for Mojave Desert Tortoises (Gopherus agassizii) (1 = cachectic, 3 = ideal, 5 = obese) was utilized and tested against pre-existing shell measurement systems (Jackson's ratio, body condition index, volume condition index, circumferential product). German captive tortoises were significantly heavier and larger than French specimens. In the Spearman's correlation matrix, the body condition score showed a statistically significant correlation with all measurement methods in the total population of captive tortoises (Testudo hermanni boettgeri), with a medium correlation strength, and a lack of correlation in free-ranging tortoises (Testudo hermanni hermanni). However, individual animal data suggested misleading results of mathematical equations in terms of body condition. Clinical evaluation of tortoises, including a body condition score, should be considered essential to provide good healthcare and should be an integral part of general examination. [ABSTRACT FROM AUTHOR]

Giant ichthyosaurs with body length estimates exceeding 20 m were present in the latest Triassic of the UK. Here we report on the discovery of a second surangular from the lower jaw of a giant ichthyosaur from Somerset, UK. The new find is comparable in size and morphology to a specimen from Lilstock, Somerset, described in 2018, but it is more complete and better preserved. Both finds are from the uppermost Triassic Westbury Mudstone Formation (Rhaetian), but the new specimen comes from Blue Anchor, approximately 10 km west along the coast from Lilstock. The more complete surangular would have been >2 m long, from an individual with a body length estimated at ~25 m. The identification of two specimens with the same unique morphology and from the same geologic age and geographic location warrants the erection of a new genus and species, Ichthyotitan severnensis gen. et sp. nov. Thin sections of the new specimen revealed the same histological features already observed in similar giant ichthyosaurian specimens. Our data also supports the previous suggestion of an atypical osteogenesis in the lower jaws of giant ichthyosaurs. The geological age and giant size of the specimens suggest shastasaurid affinities, but the material is too incomplete for a definitive referral. Ichthyotitan severnensis gen. et sp. nov., is the first-named giant ichthyosaur from the Rhaetian and probably represents the largest marine reptile formally described. [ABSTRACT FROM AUTHOR]

Energy absorption and flow through a nest is an important aspect of embryonic development in many reptile species including turtles. To date, few studies have explicitly attempted to quantify the energy flow through turtle nests, opting instead for the simplified approach offered by temperature index models. However, the quantification of the energy can provide an explicit abiotic link that can link biological models to biometeorological and ecohydrological processes and models. We investigated the energy flow through turtle nests occupying different bedrock morphologies within a Canadian Shield Rock Barren landscape, in Ontario, Canada. The taxons studied were Spotted Turtle (Clemmys guttata), Midland Painted Turtle (Chrysemys picta marginata), and Blanding's Turtle (Emydoidea blandingii). Nest temperature and soil moisture were measured in 2018 and 2019 using sensors placed in the soil adjacent to 12 turtle nest cavities. Three main rock morphologies were identified for each nest location, Crevice, Ledge, and Flat types, that are in order of decreasing bedrock percentage contact with the nest site. Ground heat flux and change in heat storage were determined using the calorimetric method for each nest, while the direction of energy flux between the atmosphere and the underlying rock was also determined. The Crevice nest morphology experienced the lowest ground heat flux on average (1.56 × 10−1 W m−2) and lowest cumulative heat storage (230 MJ) compared to the Flat (440 MJ) and Ledge (331 MJ) nests. However, over the diurnal cycle, large heat gains by Flat nests were mostly balanced out by nighttime heat losses. While Crevice nests saw the lowest daily heat storage gains, they experienced much lower heat losses over the evening period compared to the other nest types. Furthermore, we found that 59% of the energy is directed from the underlying bedrock into the Crevice nest, highlighting the importance of the bedrock in controlling thermal dynamics in the turtle nesting habitat. The lower variability in energy parameters for Crevice nest types can be attributed to higher amounts of nest‐to‐bedrock contact, compared to the flat nest types. Our results indicate that Crevice morphology may be ideal for turtles nesting at their northern limits because minimal heat loss during the evening can result in a more stable thermal incubation environment. Future conservation and habitat restoration efforts should consider the importance of bedrock morphology and prioritize the protection of Crevice nest sites. Furthermore, this work highlights important opportunities for potential interdisciplinary work between ecologists, climatologists, biologists, and hydrologists, specifically the integration of ecohydrological and biological models. This work also underscores the potential uncertainty of climate change impacts on turtle egg hatching success and nest sex ratios. [ABSTRACT FROM AUTHOR]

Introduction: Sex is a fundamental characteristic of an individual. It is therefore puzzling why in some systems sex is precisely determined by a genotype, while in others it is influenced by the environment or even subtle, not to say random, factors. Some stochasticity in sex determination would be expected if environmental conditions did not have a large sex-specific effect on fitness. Although data are only available for a small fraction of species, geckos show exceptional variability in sex determination. Methods: We tested the effects of three incubation temperatures on sex ratio and adult body size in the invasive gecko Phelsuma laticauda and the vulnerable gecko Phelsuma nigristriata. Results: We document temperature-dependent sex determination (TSD) in both species. Only females hatched at a low temperature (24°C), whereas male production peaked at an intermediate temperature (28°C) and declined, at least in P. laticauda, again at the highest temperature (31°C). Interestingly, full siblings hatched from eggs glued together during the incubation at temperatures producing both sexes are often of the opposite sex. We found no significant effect of incubation temperature on adult body length. Conclusions: Documentation of TSD in the day geckos has implications for conservation practice in environmental management of endangered species or eradication of invasive species. However, it appears that a very subtle (random?) factor may also be involved in their sex determination. In line with this, we found no significant effect of incubation temperature on adult body length. [ABSTRACT FROM AUTHOR]

Among the least studied portion of the pterosaur skeleton is the palate, which tends to be poorly preserved and commonly only visible from one side (the ventral portion). Even in well-preserved specimens, the bones tend to be fused, with the limits of individual palatal elements obscured. To shed new light on this region, we employed advanced X-ray imaging techniques on the non-pterodactyloid Kunpengopterus (Wukongopteridae), and the pterodactyloids Dsungaripterus (Dsungaripteridae), Hongshanopterus (Istiodactylidae), and Hamipterus (Hamipteridae). Our analyses revealed the presence of sutures between palatal bones in Dsungaripterus and Kunpengopterus, which resulted in different interpretations of the relation between palatine, ectopterygoid, and pterygoid, leading to a new identification of the palatal openings. Furthermore, our study shows six main observations such as the variation of the angle between the palatine rami and the variation in the relative sizes of the palatal openings. We also point out that the presence of a maxillopalatine fenestra (previously identified as postpalatine fenestra), is unique within Diapsida. Although much more work needs to be done, we showed that advanced X-ray imaging techniques open a window for understanding pterosaur cranial anatomy and provide a new perspective for investigating the evolutionary history of these flying reptiles. A study on the palatal region of pterosaurs suggests different bone interpretations and new identification of the palatal openings, pointing out that the maxillopalatine fenestra in pterosaurs is unique within Diapsida. [ABSTRACT FROM AUTHOR]

The bone-eating worm Osedax is a speciose and globally distributed clade, primarily found on whale carcasses in marine environments. The earliest fossil evidence for Osedax borings was previously described in plesiosaur and sea turtle bones from the mid-Cretaceous of the United Kingdom, representing the only unequivocal pre-Oligocene occurrences. Confirming through CT scanning, we present new evidence of Osedax borings in three plesiosaur specimens and, for the first time, identify borings in two mosasaur specimens. All specimens are from the Late Cretaceous: one from the Cenomanian of the United Kingdom, two from the Campanian of the southeastern United States, and two from the Maastrichtian of Belgium. This extends the geographic range of Osedax in the Cretaceous to both sides of the northern Atlantic Ocean. The bones contain five borehole morphotypes, potentially created by different species of Osedax, with the Cenomanian specimen containing three morphotypes within a single tooth. This combined evidence of heightened species diversity by the Cenomanian and broad geographic range by the Campanian potentially indicates an earlier origin and diversification for this clade than previously hypothesized. Preservational biases indicate that Osedax was probably even more widely distributed and speciose in the Cretaceous than apparent in the fossil record. [ABSTRACT FROM AUTHOR]

Developmental anomalies affect all species. However, the amount of data varies greatly among taxa and focuses mainly on domestic or model species, leaving some groups, like "reptiles", lacking information. To access the accumulated data regarding developmental anomalies in non-avian reptiles, we conducted a systematic bibliographic review of the available data for the past 60 years (from 1960 to 2019) and classified them accordingly to their research type (Systematic Bibliographic Review, Case Study, Environmental Study, Staging Table/Ontogenetic Study, Molecular Study, Evolutionary Study, Experimental Study), and listed the anomalies there described. We obtained 90 hits, over 50% published in the last decade. The most common study type found was "Case Studies", followed by "Environmental Studies" and "Systematic Bibliographic Reviews", and in smaller numbers, "Staging Tables and Ontogenetic Studies", "Molecular Studies", "Experimental Studies" and "Evolutionary Studies". As a result, we found 289 individual records of anomalies across all non-avian reptile groups. From this total, we registered 121 different appropriately named documented anomalies and provided names for 21 anomalies based on their description, thus naming and describing a total of 134 different unique anomalies for reptiles. [ABSTRACT FROM AUTHOR]

Evaluating the effects of temperature variations on animals plays an important role in understanding the threat of climate warming. The effects of developmental temperature on offspring performance are critical in evaluating the effects of warming temperatures on the fitness of oviparous species, but the physiological and biochemical basis of this developmental plasticity is largely unknown. In this study, we incubated eggs of the turtle Pelodiscus sinensis at low (24 °C), medium (28 °C), and high (32 °C) temperatures, and evaluated the effects of developmental temperature on offspring fitness, and metabolic enzymes in the neck and limb muscles of hatchlings. The hatchlings from eggs incubated at the medium temperature showed better fitness-related performance (righting response and swimming capacity) and higher activities of metabolic enzymes (hexokinase, HK; lactate dehydrogenase, LDH) than hatchlings from the eggs incubated at high or low temperatures. In addition, the swimming speed and righting response were significantly correlated with the HK activities in limb (swimming speed) and neck (righting response) muscles, suggesting that the developmental plasticity of energy metabolic pathway might play a role in determining the way incubation temperature affects offspring phenotypes. Integrating the fitness-related performance and the activities of metabolic enzymes, we predict that the P. sinensis from high latitude would not face the detrimental effects of climate warming until the average nest temperatures reach 32 °C. [ABSTRACT FROM AUTHOR]

Ectotherms that maintain thermal balance in the face of varying climates should be able to colonise a wide range of habitats. In lizards, thermoregulation usually appears as a variety of behaviours that buffer external influences over physiology. Basking species rely on solar radiation to raise body temperatures and usually show high thermoregulatory precision. By contrast, species that do not bask are often constrained by climatic conditions in their habitats, thus having lower thermoregulatory precision. While much focus has been given to the effects of mean habitat temperatures, relatively less is known about how seasonality affects the thermal biology of lizards on a macroecological scale. Considering the current climate crisis, assessing how lizards cope with temporal variations in environmental temperature is essential to understand better how these organisms will fare under climate change. Activity body temperatures (Tb) represent the internal temperature of an animal measured in nature during its active period (i.e. realised thermal niche), and preferred body temperatures (Tpref) are those selected by an animal in a laboratory thermal gradient that lacks thermoregulatory costs (i.e. fundamental thermal niche). Both traits form the bulk of thermal ecology research and are often studied in the context of seasonality. In this study, we used a meta‐analysis to test how environmental temperature seasonality influences the seasonal variation in the Tb and Tpref of lizards that differ in thermoregulatory strategy (basking versus non‐basking). Based on 333 effect sizes from 137 species, we found that Tb varied over a greater magnitude than Tpref across seasons. Variations in Tb were not influenced by environmental temperature seasonality; however, body size and thermoregulatory strategy mediated Tb responses. Specifically, larger species were subjected to greater seasonal variations in Tb, and basking species endured greater seasonal variations in Tb compared to non‐basking species. On the other hand, the seasonal variation in Tpref increased with environmental temperature seasonality regardless of body size. Thermoregulatory strategy also influenced Tpref, suggesting that behaviour has an important role in mediating Tpref responses to seasonal variations in the thermal landscape. After controlling for phylogenetic effects, we showed that Tb and Tpref varied significantly across lizard families. Taken together, our results support the notion that the relationship between thermal biology responses and climatic parameters can be taxon and trait dependent. Our results also showcase the importance of considering ecological and behavioural aspects in macroecological studies. We further highlight current systematic, geographical, and knowledge gaps in thermal ecology research. Our work should benefit those who aim to understand more fully how seasonality shapes thermal biology in lizards, ultimately contributing to the goal of elucidating the evolution of temperature‐sensitive traits in ectotherms. [ABSTRACT FROM AUTHOR]

Reptiles display considerable diversity in reproductive behavior, making them great models to study the neuroendocrine control of reproductive behavior. Many reptile species are seasonally breeding, such that they become reproductively active during their breeding season and regress to a nonreproductive state during their nonbreeding season, with this transition often prompted by environmental cues. In this review, we will focus on summarizing the neural and neuroendocrine mechanisms controlling reproductive behavior. Three major areas of the brain are involved in reproductive behavior: the preoptic area (POA), amygdala, and ventromedial hypothalamus (VMH). The POA and VMH are sexually dimorphic areas, regulating behaviors in males and females respectively, and all three areas display seasonal plasticity. Lesions to these areas disrupt the onset and maintenance of reproductive behaviors, but the exact roles of these regions vary between sexes and species. Different hormones influence these regions to elicit seasonal transitions. Circulating testosterone (T) and estradiol (E2) peak during the breeding season and their influence on reproduction is well‐documented across vertebrates. The conversion of T into E2 and 5α‐dihydrotestosterone can also affect behavior. Melatonin and corticosterone have generally inhibitory effects on reproductive behavior, while serotonin and other neurohormones seem to stimulate it. In general, there is relatively little information on the neuroendocrine control of reproduction in reptiles compared to other vertebrate groups. This review highlights areas that should be considered for future areas of research. Research highlights: Reptiles display considerable diversity in reproductive behavior yet are a relatively understudied group.Reptile reproduction is driven by interactions between brain regions and hormones.Reptilian reproduction is complex, and more research is needed to identify mechanisms across species. [ABSTRACT FROM AUTHOR]