Clinical features, surgical management and outcome of squamous and basal cell carcinoma in squamates and chelonians.

BACKGROUND: Squamous cell carcinoma (SCC) is one of the most commonly diagnosed neoplastic disorders in reptiles. Recently, however, it has been demonstrated that basal cell carcinomas (BCCs) are frequently misclassified as SCCs. Several histological SCC and BCC variants have been characterised and their classification may allow the establishment of appropriate prognosis estimation and treatment approaches. HYPOTHESIS/OBJECTIVES: To describe the clinical features and surgical outcomes of SCCs and BCCs diagnosed between 2010 and 2022 in reptiles. ANIMALS: Thirty-three captive reptiles (21 squamates and 12 chelonians). MATERIALS AND METHODS: Detailed clinical history, including staging and surgical outcomes, were performed. Statistical analysis assessed significant factors using Prism (v8.2.1). RESULTS: While SCC was predominantly diagnosed in lizards, BCC was most commonly diagnosed in chelonians, and both neoplasms mainly occurred in adult to aged, male individuals. Although the gross pathological findings were highly comparable between SCC and BCC, considerable variation could be seen according to the primary location (oral, cutaneous or epidermis of the shell). Humane euthanasia or noncurative intent surgeries were performed in a minority of the cases. Curative intent surgeries were successful in 19 of 27 cases during a 1- to 7-year follow-up period, yet recurrence was seen in 8 cases. The results of this study allowed the identification of significant high-risk prognostic factors for SCC and BCC in reptiles. CONCLUSIONS AND CLINICAL RELEVANCE: This study contributes to predicting the clinical behaviour and prognosis of distinct SCC and BCC histological variants, and selecting the most appropriate treatment protocol.

Mandibular gland proteomics of the Mexican alligator lizard, Abronia graminea, and the red-lipped arboreal alligator lizard, Abronia lythrochila.

A useful approach to deepen our knowledge about the origin and evolution of venom systems in Reptilia has been exploring the vast biodiversity of this clade of vertebrates in search of orally produced proteins with toxic actions, as well as their corresponding delivery systems. The occurrence of toxins in anguimorph lizards has been demonstrated experimentally or inferred from reports of the toxic effects of the oral secretions of taxa within the Varanidae and Helodermatidae families. In the present study, we have focused on two alligator lizards of the Anguidae family, the Mexican alligator lizard, Abronia graminea, and the red-lipped arboreal alligator lizard, A. lythrochila. In addition, the fine morphology of teeth of the latter species is described. The presence of a conserved set of proteins, including B-type natriuretic peptides, cysteine-rich secretory proteins, group III phospholipase A2, and kallikrein, in submandibular gland extracts was demonstrated for both Abronia species. These proteins belong to toxin families found in oral gland secretions of venomous reptile species. This finding, along with previous demonstration of toxin-producing taxa in both paleo- and neoanguimorpha clades, provides further support for the existence of a handful of conserved toxin families in oral secretions across the 100+ million years of Anguimorpha cladogenesis.

Metazoan Endoparasites of the Gecko Phyllopezus periosus (Squamata: Phyllodactylidae) Inhabiting the Rock Cliffs of a Waterfall Canyon in the Semi-Arid Region from Northeastern Brazil.

PURPOSE: This study describes the composition and infection patterns of macro endoparasites associated with the lizard Phyllopezus periosus. METHODS: We collected 115 P. periosus over 12 expeditions on the rocky cliffs of the Missão Velha waterfall canyon in northeastern Brazil. Specimens were collected by hand, during active searches conducted between 18:00 h and 23:30 h. The infection patterns were estimated using prevalence, total abundance, and mean intensity of infection for all parasites found. RESULTS: A total of 4256 parasites were collected from 104 hosts, resulting in an exceptionally high overall prevalence of 90.4%. No significant ontogenetic difference in the prevalence of infection was detected. Although juveniles exhibited a high parasite prevalence their parasite loads were significantly lower compared to adults. Six species of endoparasites were found; among these, the nematode Spauligodon oxkutzcabiensis was the most common endoparasite in the digestive tract, while the pentastomid Raillietiella mottae was the only species found in the respiratory tract. CONCLUSIONS: Infection rates in Gekkota species appear to correlate with body size, with larger individuals generally exhibiting a higher prevalence. This pattern was also observed across separate populations of P. periosus and other geckos from distinct ecological domains. The dominance of the monoxenous S. oxkutzcabiensis highlights potential transmission mechanisms, suggesting that behaviors such as limb licking after feeding may contribute to its prevalence. The occurrence of Physalopteroides venancioi, Oswaldocruzia sp., Parapharyngodon sp., Physaloptera sp., infecting P. periosus are new records for this host. These findings significantly contribute to the knowledge of host-parasite dynamics in geckos.

Microscopic structure and immunolabeling of extremely overlapped scales in some scincid, anguid, and pygopod lizards.

Skink, anguid, and pygopod lizards possess an extremely flat skin, imparting a compact and solid body and shining surface that facilitates their slider and/or fossorial movements. The present morphological study, conducted using immunohistochemistry and electron microscopy, has analyzed the microscopical morphology of extremely overlapped scales in different lizards, including species with limb reduction (scincids such as Lerista bougainvilli, Scincella lateralis, Lampropholis delicata) or legless (pygopods such as Lialis burtonis and Delma molleri and the anguid Anguis fragilis). The outer surface of the epidermis shows different micro-structures of the Oberhautchen layer containing corneous beta-proteins (CBPs) with variable immunoreactivity for these proteins. The beta-layer is relatively thick in most of these species, probably in relation to the resistance against strong mechanical forces acting on scales during the movements on harsh substrates. The scincid and anguid lizards also possess and regenerate osteoderms that reinforce scales flatness and mechanical resistance during the serpentiform or fossorial movements of these reptiles. Osteoderms are absent in pygopods. Roundish cells with a granular content are detected in the deep hinge region of scales in Lerista and Lampropholis skinks. Whether these cells may secrete substances that facilitate scale anti-friction and also determine shining of the skin surface remains to be shown.

The Phylogenetic Relationships of Major Lizard Families Using Mitochondrial Genomes and Selection Pressure Analyses in Anguimorpha.

Anguimorpha, within the order Squamata, represents a group with distinct morphological and behavioral characteristics in different ecological niches among lizards. Within Anguimorpha, there is a group characterized by limb loss, occupying lower ecological niches, concentrated within the subfamily Anguinae. Lizards with limbs and those without exhibit distinct locomotor abilities when adapting to their habitats, which in turn necessitate varying degrees of energy expenditure. Mitochondria, known as the metabolic powerhouses of cells, play a crucial role in providing approximately 95% of an organism's energy. Functionally, mitogenomes (mitochondrial genomes) can serve as a valuable tool for investigating potential adaptive evolutionary selection behind limb loss in reptiles. Due to the variation of mitogenome structures among each species, as well as its simple genetic structure, maternal inheritance, and high evolutionary rate, the mitogenome is increasingly utilized to reconstruct phylogenetic relationships of squamate animals. In this study, we sequenced the mitogenomes of two species within Anguimorpha as well as the mitogenomes of two species in Gekkota and four species in Scincoidea. We compared these data with the mitogenome content and evolutionary history of related species. Within Anguimorpha, between the mitogenomes of limbless and limbed lizards, a branch-site model analysis supported the presence of 10 positively selected sites: Cytb protein (at sites 183 and 187), ND2 protein (at sites 90, 155, and 198), ND3 protein (at site 21), ND5 protein (at sites 12 and 267), and ND6 protein (at sites 72 and 119). These findings suggested that positive selection of mitogenome in limbless lizards may be associated with the energy requirements for their locomotion. Additionally, we acquired data from 205 mitogenomes from the NCBI database. Bayesian inference (BI) and Maximum Likelihood (ML) trees were constructed using the 13 mitochondrial protein-coding genes (PCGs) and two rRNAs (12S rRNA and 16S rRNA) from 213 mitogenomes. Our phylogenetic tree and the divergence time estimates for Squamata based on mitogenome data are consistent with results from previous studies. Gekkota was placed at the root of Squamata in both BI and ML trees. However, within the Toxicofera clade, due to long-branch attraction, Anguimorpha and (Pleurodonta + (Serpentes + Acrodonta)) were closely related groupings, which might indicate errors and also demonstrate that mitogenome-based phylogenetic trees may not effectively resolve long-branch attraction issues. Additionally, we reviewed the origin and diversification of Squamata throughout the Mesozoic era, suggesting that Squamata originated in the Late Triassic (206.05 Mya), with the diversification of various superfamilies occurring during the Cretaceous period. Future improvements in constructing squamate phylogenetic relationships using mitogenomes will rely on identifying snake and acrodont species with slower evolutionary rates, ensuring comprehensive taxonomic coverage of squamate diversity, and increasing the number of genes analyzed.

Staphylococci, Reptiles, Amphibians, and Humans: What Are Their Relations?

Reptiles and amphibians are largely present in many environments, including domestic areas when they are kept as pet animals. They often harbor zoonotic pathogens, which can pose a serious risk of infection for humans, mainly immunocompromised individuals, the elderly, children, and pregnant women. Several studies have been carried out to verify the role of cold-blooded animals in the epidemiology of some bacteria, mainly Salmonella, whereas scarce attention has been focused on these animals as a source of staphylococci. These bacteria are often antimicrobial-resistant and they act as opportunistic pathogens, which can cause relevant infections in humans and animals, both domestic and wild. Asymptomatic reptiles and amphibians often harbor staphylococcal strains, such as Staphylococcus aureus and coagulase-negative Staphylococcus spp.; however, these bacteria have been associated with clinical conditions that usually appear in animals under stress conditions. In all cases, greater attention should also be focused on staphylococci in cold-blooded animals due to their implications in human and veterinary medicine.

hsp70 PCR-RFLP as an alternative tool to identify Sauroleishmania species.

Sauroleishmania spp. comprises one of the four Leishmania subgenera, which has been historically considered a non-pathogenic protozoan of reptiles. However, some strains appear to be transiently infective to mammals, and recent findings have detected these parasites in dogs and humans in areas where leishmaniasis is endemic. Herein, the digestion pattern of PCR-RFLP of the 234 bp-hsp70 fragment was evaluated as a simpler and cheaper tool to distinguish the Sauroleishmania species from the other Leishmania subgenera. As a result, the digestion of the 234 bp-hsp70 fragments with HaeIII produced a banding pattern specific to the four Sauroleishmania strains assessed. This technique could contribute to the identification of Leishmania parasites isolated from sandflies, reptiles, or even mammals in fieldworks as an alternative to the use of laborious and expensive methodologies.

Environmental and anthropogenic factors mediating the functional connectivity of the mesquite lizard along the eastern Trans-Mexican Volcanic Belt.

Functional connectivity, the extent to which a landscape facilitates or impedes the dispersal of individuals across the landscape, is a key factor for the survival of species. Anthropogenic activities, such as urbanization, agriculture and roads, negatively impact functional connectivity of most species, particularly low-vagility species like lizards. Here, we examine how a landscape modified by anthropogenic activities affects the functional connectivity, at both broad and fine scales, of a widely distributed generalist lizard Sceloporus grammicus in the eastern Trans-Mexican Volcanic Belt, Mexico. We estimated for the first time the species' genetic structure, gene flow and functional connectivity in agricultural and forest zones using genomic data, a comprehensive landscape characterization and novel methods including gravity models. Our results showed not only marked genetic differentiation across the study region but also that functional connectivity is maintained for tens of kilometres despite S. grammicus low vagility. Specifically, we found that substrate and air temperature facilitated connectivity over broad and fine scales, respectively, while agricultural cover, relative humidity and slope were important for connectivity and gene flow. Contrastingly, forest cover and roads favoured (broad-scale) and limited (fine-scale) connectivity, likely associated with movement facilitated by small forest patches and with thermoregulation. Altogether, these results support that S. grammicus alternates its thermoregulatory behaviour depending on the distance travelled and the habitat environmental conditions, and that it can disperse through relatively modified landscapes, mainly using agricultural zones. The information obtained is crucial to understanding the response of lizards to current anthropogenic pressures and their potential to adapt.

Lizard Body Temperature Acquisition and Lizard Recognition Using Artificial Intelligence.

The acquisition of the body temperature of animals kept in captivity in biology laboratories is crucial for several studies in the field of animal biology. Traditionally, the acquisition process was carried out manually, which does not guarantee much accuracy or consistency in the acquired data and was painful for the animal. The process was then switched to a semi-manual process using a thermal camera, but it still involved manually clicking on each part of the animal's body every 20 s of the video to obtain temperature values, making it a time-consuming, non-automatic, and difficult process. This project aims to automate this acquisition process through the automatic recognition of parts of a lizard's body, reading the temperature in these parts based on a video taken with two cameras simultaneously: an RGB camera and a thermal camera. The first camera detects the location of the lizard's various body parts using artificial intelligence techniques, and the second camera allows reading of the respective temperature of each part. Due to the lack of lizard datasets, either in the biology laboratory or online, a dataset had to be created from scratch, containing the identification of the lizard and six of its body parts. YOLOv5 was used to detect the lizard and its body parts in RGB images, achieving a precision of 90.00% and a recall of 98.80%. After initial calibration, the RGB and thermal camera images are properly localised, making it possible to know the lizard's position, even when the lizard is at the same temperature as its surrounding environment, through a coordinate conversion from the RGB image to the thermal image. The thermal image has a colour temperature scale with the respective maximum and minimum temperature values, which is used to read each pixel of the thermal image, thus allowing the correct temperature to be read in each part of the lizard.

A rapid inventory of amphibians, squamates, and bats of Mata de Plátano Field Station and Nature Reserve, Arecibo, Puerto Rico.

Puerto Rico harbors a diverse vertebrate fauna with high levels of endemism. However, while several books for vertebrate diversity and local checklists for birds have been published, checklists of amphibians, reptiles, and bats are lacking or nonexistent at both local and regional scales. In this study, we documented the amphibian, reptile, and bat faunas at Mata de Plátano Field Station and Nature Reserve, in Arecibo, Puerto Rico. We document four species of amphibians, seven lizards, three snakes, and nine bats. Despite prior works using samples from this nature reserve, this represents the first vertebrate checklist for the Mata de Plátano Field Station and Nature Reserve. We provide additional natural history observations based on our survey results and highlight the importance of including local and regional checklists of species for downstream research and conservation.

Bacterial pathogens in Ixodes ricinus collected from lizards Lacerta agilis and Zootoca vivipara in urban areas of Wroclaw, SW Poland- preliminary study.

The aim of this study was to determine the level of infection of Ixodes ricinus ticks with pathogens (Borrelia spp., Rickettsia spp., and Anaplasma spp.) collected from Lacerta agilis and Zootoca vivipara lizards in the urban areas of Wroclaw (SW Poland). The study was carried out in July-August 2020. Lizards were caught by a noose attached to a pole or by bare hands, identified by species, and examined for the presence of ticks. Each lizard was then released at the site of capture. Ticks were removed with tweezers, identified by species using keys, and molecular tests were performed for the presence of pathogens. From 28 lizards (17 specimens of Z. vivipara and 11 specimens of L. agilis) a total of 445 ticks, including 321 larvae and 124 nymphs, identified as I. ricinus were collected. A larger number of ticks were obtained from L. agilis compared to Z. vivipara. Molecular tests for the presence of pathogens were performed on 445 specimens of I. ricinus. The nested PCR method for the fla gene allowed the detection of Borrelia spp. in 9.4% of ticks, and it was higher in ticks from L. agilis (12.0%) than from Z. vivipara (1.0%). The RFLP method showed the presence of three species, including two belonging to the B. burgdorferi s.l. complex (B. lusitaniae and B. afzelii), and B. miyamotoi. The overall level of infection of Rickettsia spp. was 19.3%, including 27.2% in ticks collected from Z. vivipara and 17.0% from L. agilis. Sequencing of randomly selected samples confirmed the presence of R. helvetica. DNA of Anaplasma spp. was detected only in one pool of larvae collected from L. agilis, and sample sequencing confirmed the presence of (A) phagocytophilum. The research results indicate the important role of lizards as hosts of ticks and their role in maintaining pathogens in the environment including urban agglomeration as evidenced by the first recorded presence of (B) miyamotoi and (A) phagocytophilum in I. ricinus ticks collected from L. agilis. However, confirmation of the role of sand lizards in maintaining (B) miyamotoi and A. phagocytophilum requires more studies and sampling of lizard tissue.

Endoparasite Infections in Captive Inland Bearded Dragons (Pogona vitticeps) in Italy.

The inland bearded dragon (Pogona vitticeps) is a lizard species commonly kept as a pet worldwide. Endoparasites are among the most important pathogens affecting bearded dragons. The aim of this study was to evaluate the endoparasites in captive P. vitticeps in Italy. Faecal samples from 30 P. vitticeps were analysed by fresh faecal smears, flotation tests, the Mini-FLOTAC technique, and a rapid immunoassay to detect Cryptosporidium spp. To search for microsporidia, PCR and sequencing were performed on the faecal samples. Data were statistically analysed. The overall positivity rate for endoparasites was 83.3% (25/30). The identified endoparasites were oxyurids (17/30, 56.7%), Isosospora amphiboluri (13/30, 43.3%), Encephalitozoon pogonae (4/18, 22.22%), and Cryptosporidium sp. (1/30, 3.33%). The positivity for protozoa was significantly higher in juveniles compared to adults. Moreover, the frequency of clinical signs was significantly higher in the positive animals. The results obtained here emphasize the importance of regular veterinary examinations of captive P. vitticeps, aimed at the diagnosis, treatment, and control of endoparasites. This study is one of the largest surveys on microsporidia infections in living bearded dragons, suggesting that E. pogonae may be widespread in this lizard.

Seasonal dietary changes relate to gut microbiota composition depending on the host species but do not correlate with gut microbiota diversity in arthropod-eating lizards.

The animal gut microbiota is strongly influenced by environmental factors that shape their temporal dynamics. Although diet is recognized as a major driver of gut microbiota variation, dietary patterns have seldom been linked to gut microbiota dynamics in wild animals. Here, we analysed the gut microbiota variation between dry and rainy seasons across four Sceloporus species (S. aeneus, S. bicanthalis, S. grammicus and S. spinosus) from central Mexico in light of temporal changes in diet composition. The lizard microbiota was dominated by Firmicutes (now Bacillota) and Bacteroidota, and the closely related species S. aeneus and S. bicanthalis shared a great number of core bacterial taxa. We report species-specific seasonal changes in gut microbiota diversity and composition: greater alpha diversity during the dry compared to the rainy season in S. bicanthalis, the opposite pattern in S. aeneus, and no seasonal differences in S. grammicus and S. spinosus. Our findings indicated a positive association between gut bacterial composition and dietary composition for S. bicanthalis and S. grammicus, but bacterial diversity did not increase linearly with dietary richness in any lizard species. In addition, seasonality affected bacterial composition, and microbial community similarity increased between S. aeneus and S. bicanthalis, as well as between S. grammicus and S. spinosus. Together, our results illustrate that seasonal variation and dietary composition play a role in shaping gut microbiota in lizard populations, but this is not a rule and other ecological factors influence microbiota variation.

Lizards and the enzootic cycle of Borrelia burgdorferi sensu lato.

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.

Pathogenic Potential of Opportunistic Gram-Negative Bacteria Isolated from the Cloacal Microbiota of Free-Living Reptile Hosts Originating from Bulgaria.

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.

Hidden social complexity behind vocal and acoustic communication in non-avian reptiles.

Social interactions are inevitable in the lives of most animals, since most essential behaviours require interaction with conspecifics, such as mating and competing for resources. Non-avian reptiles are typically viewed as solitary animals that predominantly use their vision and olfaction to communicate with conspecifics. Nevertheless, in recent years, evidence is mounting that some reptiles can produce sounds and have the potential for acoustic communication. Reptiles that can produce sound have an additional communicative channel (in addition to visual/olfactory channels), which could suggest they have a higher communicative complexity, the evolution of which is assumed to be driven by the need of social interactions. Thus, acoustic reptiles may provide an opportunity to unveil the true social complexity of reptiles that are usually thought of as solitary. This review aims to reveal the hidden social interactions behind the use of sounds in non-avian reptiles. Our review suggests that the potential of vocal and acoustic communication and the complexity of social interactions may be underestimated in non-avian reptiles, and that acoustic reptiles may provide a great opportunity to uncover the coevolution between sociality and communication in non-avian reptiles. This article is part of the theme issue 'The power of sound: unravelling how acoustic communication shapes group dynamics'.

Selective extinction and habitat nestedness are the main drivers of lizard nestedness in the Zhoushan Archipelago.

Nested subset pattern (nestedness) is an important part of the theoretical framework of island biogeography and community ecology. However, most previous studies often used nestedness metrics or randomization algorithms that are vulnerable to type I error. In this study, we investigated the nestedness of lizard assemblages on 37 islands in the Zhoushan Archipelago, China. We used the line-transect method to survey species occurrence, abundance, and habitat types of lizards on 37 islands during 2 breeding seasons in 2021 and 2022. We applied the nested metric WNODF and the conservative rc null model to control for type I error and quantify the significance of nestedness. Spearman rank correlations were used to evaluate the role of 4 habitat variables (island area, 2 isolation indices, and habitat diversity) and 4 ecological traits (body size, geographic range size, clutch size, and minimum area requirement) in generating nestedness. The results of WNODF analyses showed that lizard assemblages were significantly nested. The habitat-by-site matrix estimated by the program NODF was also significantly nested, supporting the habitat nestedness hypothesis. The nestedness of lizard assemblages were significantly correlated with island area, habitat diversity, clutch size, and minimum area requirement. Overall, our results suggest that selective extinction and habitat nestedness were the main drivers of lizard nestedness in our system. In contrast, the nestedness of lizard assemblages was not due to passive sampling or selective colonization. To maximize the number of species preserved, our results indicate that we should protect both large islands with diverse habitats and species with large area requirement and clutch size.

Fossil-informed biogeographic analysis suggests Eurasian regionalization in crown Squamata during the early Jurassic.

Background: Squamata (lizards, snakes, and amphisbaenians) is a Triassic lineage with an extensive and complex biogeographic history, yet no large-scale study has reconstructed the ancestral range of early squamate lineages. The fossil record indicates a broadly Pangaean distribution by the end- Cretaceous, though many lineages (e.g., Paramacellodidae, Mosasauria, Polyglyphanodontia) subsequently went extinct. Thus, the origin and occupancy of extant radiations is unclear and may have been localized within Pangaea to specific plates, with potential regionalization to distinct Laurasian and Gondwanan landmasses during the Mesozoic in some groups. Methods: We used recent tectonic models to code extant and fossil squamate distributions occurring on nine discrete plates for 9,755 species, with Jurassic and Cretaceous fossil constraints from three extinct lineages. We modeled ancestral ranges for crown Squamata from an extant-only molecular phylogeny using a suite of biogeographic models accommodating different evolutionary processes and fossil-based node constraints from known Jurassic and Cretaceous localities. We hypothesized that the best-fit models would not support a full Pangaean distribution (i.e., including all areas) for the origin of crown Squamata, but would instead show regionalization to specific areas within the fragmenting supercontinent, likely in the Northern Hemisphere where most early squamate fossils have been found. Results: Incorporating fossil data reconstructs a localized origin within Pangaea, with early regionalization of extant lineages to Eurasia and Laurasia, while Gondwanan regionalization did not occur until the middle Cretaceous for Alethinophidia, Scolecophidia, and some crown Gekkotan lineages. While the Mesozoic history of extant squamate biogeography can be summarized as a Eurasian origin with dispersal out of Laurasia into Gondwana, their Cenozoic history is complex with multiple events (including secondary and tertiary recolonizations) in several directions. As noted by previous authors, squamates have likely utilized over-land range expansion, land-bridge colonization, and trans-oceanic dispersal. Tropical Gondwana and Eurasia hold more ancient lineages than the Holarctic (Rhineuridae being a major exception), and some asymmetries in colonization (e.g., to North America from Eurasia during the Cenozoic through Beringia) deserve additional study. Future studies that incorporate fossil branches, rather than as node constraints, into the reconstruction can be used to explore this history further.

Comparative anatomy and evolution of the atlantoaxial complex in the fossorial lineage Amphisbaenia (Squamata: Lacertoidea).

The atlas and axis are the first two vertebrae from the cervical series; these two vertebrae are responsible for neck flexion, extension, and rotation movements, while providing insertion points for muscles and tendons. Amphisbaenia is a group of fossorial squamates known for having four distinctive head shapes, which are related to different excavation methods. However, little is known about the relationship between these different digging patterns and the anatomy and evolution of the atlantoaxial complex. In this study, we used computed microtomography data to describe in detail of the atlantoaxial complex for 15 species, belonging to all six current families of Amphisbaenia. Furthermore, we evaluate evolutionary scenarios of selected characters related to the atlantoaxial complex in the most recent phylogeny for Amphisbaenia, using the criteria of parsimony and maximum likelihood. Our results indicate that the evolutionary pattern of the atlantoaxial complex presents a diversification in its morphology that is not always correlated with the shape of the head. This analysis reinforces the hypothesis of remarkable morphological convergences in the evolutionary history of Amphisbaenia. Additionally, some of the characters studied may represent independent evolution through convergence in some cases (e.g., horizontal axis of the neural column) and parallelism in others (e.g., present or absent from the transverse process).

Vertebrates can be more important pollinators than invertebrates on islands: the case of Malva (=Lavatera) arborea L.

Premise of the study: On islands, flowering plants tend to be more generalist in their pollination needs, as insects (the main pollinators of flowering plants) are underrepresented in these ecosystems compared to the mainland. In addition, some vertebrate species that are typically insectivorous or granivorous on the mainland are forced to broaden their diet and consume other resources such as nectar or pollen on the islands. The shrub Malva arborea, with its large and colourful flowers, attracts different groups of potential pollinators. This study aimed to compare the effectiveness of vertebrates versus insects in an insular population of M. arborea and to investigate its reproductive system. Methods: For three groups of taxa (insects, birds and lizards), we assessed the two components of pollination effectiveness: (i) the quantitative component (i.e. number of visits and number of flowers contacted) through direct observations of flowers; and (ii) the qualitative component (fruit and seed set, number and size of seeds and proportion of seedling emergence) through pollinator exclusion experiments. Key results: Vertebrates (birds and lizards) were quantitatively the most effective pollinators, followed by insects. However, when all three groups visited the flowers, fruit and seed set were higher than when any of them were excluded. We also found that M. arborea has hermaphrodite flowers and is able to reproduce by autogamy, although less efficiently than when pollinated by animals. Conclusions: Both vertebrates and insects play an important role in the reproduction of M. arborea. Although the plant does not need pollinators to produce seeds, its reproductive success increases when all pollinators are allowed to visit the flowers. Besides providing new information on M. arborea, these findings may help to better understand the role of different pollinator groups in the reproduction of other plant species, especially on islands where the co-occurrence of vertebrate and invertebrate pollination in the same plant species is usual.