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Indian fossil Squamata and Anura are known from the Upper Cretaceous-lower Paleocene Deccan Trap associated sediments for over last one century. However, current knowledge on their taxonomy and stratigraphic implications is poor for their scarce and fragmentary nature and lack of any stratigraphic constraints. We report newly found fossil Squamata and Anura from the new intertrappean locality Bharudpura in Malwa Plateau and describe (i) Scincomorpha (Scincoidea) lizards based on taxonomic study of dentary, maxilla and osteoderms, (ii) Anguimorpha (Anguidae) lizards based on osteoderms, (iii) Squamata indeterminate based on a vertebrae and (iv) Anura (Ranidae, Ranoidea and Anuran indeterminate) based on a ilium, a sacral vertebrae and single dentary. Currently, it is not possible to ascertain if the different fossil specimens belong to a single or more taxa. The lowermost lava pile of Mandleshwar and Kalisindh formations, associated with multiple intertrappean beds including the new Bharudpura fossil locality, have yielded40Ar/39Ar plateau ages from 66.834 Ma, the oldest Deccan Trap flow dated so far in India to 66.352 Ma. The present study records their earliest occurrence in India, from intertrappean associated with oldest Deccan Trap lava pile that erupted during magnetochron C30n of Maastrichtian in the Malwa Plateau. [ABSTRACT FROM AUTHOR]

Channelrhodopsins (ChRs) are light-gated ion channels widely used to optically activate or silence selected electrogenic cells, such as individual brain neurons. Here, we describe identifying and characterizing a set of anion-conducting ChRs (ACRs) from diverse taxa and representing various branches of the ChR phylogenetic tree. The Mantoniella squamata ACR (MsACR1) showed high sensitivity to yellow-green light (λmax at 555 nm) and was further engineered for optogenetic applications. A single amino-acid substitution that mimicked red-light-sensitive rhodopsins like Chrimson shifted the photosensitivity 20 nm toward red light and accelerated photocurrent kinetics. Hence, it was named red and accelerated ACR, raACR. Both wild-type and mutant are capable optical silencers at low light intensities in mouse neurons in vitro and in vivo, while raACR offers a higher temporal resolution. [ABSTRACT FROM AUTHOR]

Although hissing is a common strategy of defence used by snakes, especially of the Phytonidae and Boidae families, few studies have described in detail the acoustics components of this behaviour. Here we gathered eight recordings from six different boas from Brazil and extracted acoustic measurements from their hissing sounds. We also examined the potential of our measurements to encode individual identity using discriminant function analyses (DFAs) and to correlate with body length using linear mixed models (LMMs). Boas produce from four to 12 hisses per minute (7.13 ± 3.04) evoked by a negative stimulus, a visual looming stimulus generated by researcher’s approach. Each hiss usually has two parts (the first louder part and the second softer part) that are basically broadband white noises split by a short silent interval. The first hiss part also has more frequency modulations and narrower bandwidth than the second hiss part. The DFAs correctly assigned all hisses to their correspondent individuals in the testing data. The first discriminant function explained most of the variance (⩾84%) in the discrimination between groups for the entire hiss and for both hiss parts in the training data subset. Frequency parameters and spectral entropy (for entire hiss and hiss part 1) and the mean frequency and duration (for hiss part 2) were the strongest absolute loadings in the DFAs. Intraspecific morphological traits (e.g. sexual dimorphism and ontogenetic variations) may influence the sound parameters, as detected by individual variations and the tendency for larger individuals to produce lower frequency hisses. Further studies may investigate these aspects in detail, including anatomy of the snake’s larynx and experiments with different types of predators. [ABSTRACT FROM AUTHOR]

Kotschy’s gecko, Mediodactylus kotschyi, is native to the Eastern part of the Mediterranean Basin and a successful colonizer, with an extensive distribution across the Balkans and outside its native range. In Serbia, it was presumed native in Prizren (Kosovo and Metohija province) and introduced across the remaining territory. To explore the origin of Serbian Kotschy’s gecko, we collected specimens from most of the Serbian populations where the species was recorded and assessed their phylogenetic relationships based on three mtDNA markers (COI, cytb, 16S rRNA) under Maximum Likelihood (ML) and Bayesian Inference (BI) approaches. First, our results support that the specimens found in Serbia belong to M. kotschyi. Second, all populations except Prizren belong to the subspecies M. kotschyi skopjensis. Furthermore, the Italian populations are sister to the specimens from Prizren, suggesting a Balkan origin for these populations, which settled in Apulia likely through ancient human-mediated dispersion. The small genetic differentiation found suggests that Kotschy’s gecko rapidly colonized the Central Balkans, originating from Northern Greece and North Macedonia. The results also suggest a story of multiple, complex (most likely) human-mediated introductions. However, further studies should be conducted to properly elucidate the colonization pathways, and to truly disentangle the potential fast natural range expansion from an anthropogenic dispersion of this gecko species. [ABSTRACT FROM AUTHOR]

The evolution of limb reduction in squamates is a classic example of convergence, but the skeletal morphological patterns associated with it are underexplored. To provide insights on the biomechanical and developmental consequences of transitions to limb reduction, we use geometric morphometrics to examine the morphology of pectoral and pelvic girdles in 90 species of limb-reduced skinks and their fully limbed relatives. Clavicle shapes converge towards an acute anterior bend when forelimbs are lost but hindlimbs are retained—a morphology typical of sand-swimmers. This may either indicate functional adaptations to locomotion in fine substrates, or a developmental consequence of complete limb loss. The shape of limb-bearing elements of both girdles (coracoid and pelvis) instead closely mirrors limb reduction, becoming more simplified as undulation replaces limbed locomotion. Integration between girdles decreases in taxa lacking elements of the forelimbs but not hindlimbs, indicating differential selection on each girdle in response to distinct locomotory strategies. However, this pattern becomes less clear when considering phylogenetic history, perhaps because it is limited to one specific clade (Lerista). We show how the functional demands of locomotion can induce changes at different levels of organismal organization, including both external and internal structures. [ABSTRACT FROM AUTHOR]

Squamates have independently evolved an elongate, limb-reduced body form numerous times. This transition has been proposed to involve either changes to regulatory gene expression or downstream modification of target enhancers to produce a homogeneous, deregionalized axial skeleton. Analysis of vertebral morphology has suggested that regionalization is maintained in snake-like body forms, but morphological variation in the other primary component of the axial skeleton, the dorsal ribs, has not been previously examined. We quantified rib morphology along the anterior–posterior axis in limbed and snake-like squamates to test different regionalization models. We find that the relative position of regional boundaries remains consistent across taxa of differing body types, including in the homoplastic evolution of snake-like body forms. The consistent retention of regional boundaries in this primaxial domain is uncorrelated with more plastic abaxial region markers. Rather than loss of regions, rib shape at the anterior and posterior of the axis converges on those in the middle, resulting in axial regions being distinguishable by allometric shape changes rather than by discrete morphologies. This complexity challenges notions of deregionalization, revealing a nuanced evolutionary history shaped by shared functions. [ABSTRACT FROM AUTHOR]

Elapids of the genus Micrurus actively search for their prey. Here we present new information on the foraging ecology of the aquatic coral snake Micrurus surinamensis based on observations in the western Amazon of Brazil. Eleven individuals of M. surinamensis were observed at night, four of them moving, four hunting in ambush posture, and three actively hunting. Here, we show that M. surinamensis is active mainly at night in aquatic environments and may also be active on the terrestrial environments. Land activity may be related with the search for fish which may eventually be found in this substrate, as well as with the search for water bodies, following the hydrological cycles of flooding and drought. When hunting, the snake uses both foraging modes, being able to actively search for its prey, or ambush it, by keeping the body partially in the water, with the head on the surface. Due to the greater availability of aquatic environments and available prey (fish), M. surinamensis should be more abundant in floodplain forest ecosystems. Additional field observations may help in elucidating the biology on this ecologically differentiated species within the genus Micrurus. [ABSTRACT FROM AUTHOR]

I here describe lacertid and snake remains from the classic Middle Miocene (MN 6) locality Bonanza of the Devínska Kobyla Hill near Bratislava (Slovakia). The locality is famous for being a type locality of an early seal Devinophoca Koretsky & Holec, 2002. During the Middle Miocene, the area of Devínska Nová Ves was part of an archipelago in the western part of the Central Paratethys in the northern part of the Vienna basin. The fossils described here comprise an incomplete left maxilla of a lacertid lizard and an articulated portion of a vertebral column of a small colubrid snake with several ribs still attached. The maxilla is tentativelly allocated here to Lacerta Linnaeus, 1758 and is a rare instance of the occurrence of the clade Lacertidae Oppel, 1811 in this environment during the Middle Miocene. Moreover, it represents the oldest known occurence of this clade in Slovakia. Articulated snake specimens from the Cenozoic are rare and although only party articulated, the specimen from Bonanza is therefore exceptional. On the basis of vertebrae alone, determination of fossil colubrids is very difficult. The morphology of the Bonanza specimen is most similar to the extant Dolichophis Gistel, 1868, as also to other small fossil snakes assigned to 'Coluber' Linnaeus, 1758 when that genus was a catch-all grade taxon recognised from both Europe and North America, notably 'Coluber' dolnicensis Szyndlar, 1987 and 'Coluber' pouchetii (Rochebrune, 1880). Because the potentially closest living relative of the European Miocene 'Coluber' is Dolichophis, I assigned tentatively the material from Bonanza to cf. Dolichophis, rather than to the wastebasket taxon 'Coluber'. [ABSTRACT FROM AUTHOR]

We here describe abundant new fossil material of amphibians and reptiles from different late Neogene localities of northern Greece: the Early Pliocene (MN 14) of Spilia 0, Spilia 1, and Spilia 2; the Early Pliocene (MN 15) of Spilia 3, Spilia 4, Spilia 5, and Vevi; and the Late Miocene or Pliocene of Chalicorrema and Rema Marmara. These new late Neogene herpetofaunas are highly diverse, documenting a considerably rich herpetofauna allowing the identification of at least two salamander, seven frog, two turtle, seven lizard, and eight snake taxa. Salamanders are represented by the salamandrid genera Ommatotriton and Ichthyosaura. Frogs are represented by the bombinatorid Bombina, the discoglossids Latonia cf. ragei and Latonia sp., the pelobatid Pelobates aff. praefuscus and Pelobates sp., the ranids Pelophylax and Rana cf. dalmatina, the hylid Hyla gr. arborea, and the bufonid Bufotes gr. viridis. Turtles are represented by the emydid Emys and an indeterminate geoemydid. Lizards are represented by the scincid Ophiomorus, two lacertids (one of which potentially pertaining to Lacerta), amphisbaenians, agamids, the anguid Pseudopus, and a potential varanid. Snakes are represented by the erycid Eryx, the natricid Natrix aff. rudabanyaensis, a small-sized elapid, an "Oriental viper", the colubriforms Periergophis and Paraxenophis, as well as two further distinct but still indeterminate morphotypes of colubriforms. For the material from Spilia tentatively referred to Ommatotriton, this is only the third occurrence in the fossil record globally. The new material of Ichthyosaura and Bombina mark the first documentation of these genera in the Greek fossil record. Abundant cranial and postcranial material from Spilia is tentatively referred to Latonia ragei, a taxon previously known from the Early Miocene of Western Europe. The new record of Pelobates represents the oldest documented occurrences of the genus in the Greek fossil record. Interestingly, the Pelobates from Spilia bears much resemblance to an extinct taxon, Pelobates aff. praefuscus, which is otherwise known from the Late Miocene of the Caucasus, and not to the extant species that currently inhabits the area. The identification of Pelophylax and Rana adds to the rather poor Neogene record of ranids from Greece. Particularly for the case of Rana cf. dalmatina from Spilia 4, this corresponds to the only documented occurrence of this extant taxon in the Greek fossil record. Similarly, the identification of Hyla gr. arborea in Spilia 1, Spilia 3, and Spilia 4, marks only the third documented occurrence of this genus in the Greek fossil record. The Bufotes material from Spilia 1, Spilia 3, and Spilia 4 represents the first documented fossil occurrence of the extant Bufotes viridis complex in Greece. The material of Emys gr. orbicularis from Vevi marks the only known pre-Quaternary record of the genus in Greece and one of the only few Neogene members of the genus known from Europe. The scincid Ophiomorus is identified in Spilia 4, known from several cranial and postcranial remains, well outside the extant range of the genus. Practically, the Spilia Ophiomorus is only the fourth known fossil occurrence of this extant genus globally and also represents one of its oldest known occurrences. Material from Spilia 1 and Spilia 3 is tentatively referred to cf. Lacerta sp., and this would mark the first known occurrence of this emblematic extant genus in the Greek fossil record, denoting the presence of the genus since at least the Early Pliocene. The new amphisbaenian specimens from Spilia 4 add to the recently described single vertebra from the same locality, and represent the youngest occurrence of amphisbaenians from continental Eastern Europe. The new agamid material from Vevi and Chalicorrema add substantially to the record of this group, which was in Greece so far known exclusively from the latest Miocene/earliest Pliocene of Maramena. A similarly important addition is the record of Pseudopus from Spilia 4, as this genus had been known in the Greek fossil record only from a very few localities. The potential varanid from Spilia represents one of the few Pliocene occurrences of this group in Europe. We identify Natrix aff. rudabanyaensis among the material from Spilia 0, Spilia 4, and Vevi, adding to the previously known record of this taxon from Maramena, however, its precise species level assignment should await a revision of Neogene European Natrix spp. The find of a small elapid from Spilia 4 represents the youngest occurrence of a coral snake from Europe, extending their statigraphic range up to the Early Pliocene (MN 14). Periergophis and Paraxenophis, two bizarre snakes, so far exclusively known from their type locality in Maramena, could be also present here, even if tentatively identified. Most notably, the new material from these localities comprises forms that are now extinct (e.g., Periergophis and Paraxenophis) or extirpated from Europe (e.g., Latonia, Varanidae, Elapidae) but at the same time also loudly attests the emergence of the extant genera that dominate the extant herpetofaunas of Greece (Ichthyosaura, Bombina, Pelobates, Pelophylax, Rana, Hyla, Bufotes, Emys, Ophiomorus, Lacerta, Pseudopus, Eryx, and Natrix), for some of which their fossil record is documented here for the first time in the area. [ABSTRACT FROM AUTHOR]

Environmental factors and interspecific interactions, such as competition and facilitation, can shape species' geographic ranges. Here, we tested the relationship between geographic range overlap of squamate sister species, and their divergence in body size, diel activity, and microhabitat use. Competition theory predicts that sister species with similar traits will overlap less geographically than sister pairs with dissimilar traits. However, similar distributions may present similar selective pressures and favour similar adaptations, such that habitat filtering may result in species with more similar traits in sympatry. Across 1434 sister species contrasts, we found little relationship between range overlap and niche divergence. In some models, the divergence in body size and microhabitat use marginally increased with sympatry, while in other models, sympatric sisters had similar activity times. However, the low R‐squared values of almost all these models lend only weak support to predictions from competition or habitat filtering theories. Sympatric sister species within the same biome showed more similar activity times than expected, lending some support to habitat filtering. Niche divergence in allopatry or sympatry, as calculated using a multi‐trait dissimilarity index, did not show a phylogenetic signal, and niches of sister species from different squamate clades did not deviate significantly from the null expectation. Overall, niche divergence or convergence, across the axes we explored, is not a prerequisite for regional species co‐occurrence. We suggest here that the lack of consistent support for either limiting similarity or habitat filtering may reflect that both these forces act as transient phenomena. More fine‐grained analyses, in space and time, would be needed to detect their fingerprints. Thus, coexistence in the face of competition can arise due to various evolutionary and biogeographic mechanisms, acting concurrently or asynchronously. [ABSTRACT FROM AUTHOR]

Squamate reptiles are central for studying phenotypic correlates of evolutionary transitions from oviparity to viviparity because these transitions are numerous, with many of them being recent. Several models of life‐history theory predict that viviparity is associated with increased female size, and thus more female‐biased sexual size dimorphism (SSD). Yet, the corresponding empirical evidence is overall weak and inconsistent. The lizard Zootoca vivipara, which occupies a major part of Northern Eurasia and includes four viviparous and two non‐sister oviparous lineages, represents an excellent model for testing these predictions. We analysed how sex‐specific body size and SSD is associated with parity mode, using body length data for nearly 14,000 adult individuals from 97 geographically distinct populations, which cover almost the entire species' range and represent all six lineages. Our analyses controlled for lineage identity, climatic seasonality (the strongest predictor of geographic body size variation in previous studies of this species) and several aspects of data heterogeneity. Parity mode, lineage and seasonality are significantly associated with female size and SSD; the first two predictors accounted for 14%–26% of the total variation each, while seasonality explained 5%–7%. Viviparous populations exhibited a larger female size than oviparous populations, with no concomitant differences in male size. The variation of male size was overall low and poorly explained by our predictors. Albeit fully expected from theory, the strong female bias of the body size differences between oviparous and viviparous populations found in Z. vivipara is not evident from available data on three other lizard systems of closely related lineages differing in parity mode. We confront this pattern with the data on female reproductive traits in the considered systems and the frequencies of evolutionary changes of parity mode in the corresponding lizard families and speculate why the life‐history correlates of live‐bearing in Z. vivipara are distinct. Comparing conspecific populations, our study provides the most direct evidence for the predicted effect of parity mode on adult body size but also demonstrates that the revealed pattern may not be general. This might explain why across squamates, viviparity is only weakly associated with larger size. [ABSTRACT FROM AUTHOR]

Myrmecophagy is one of the most common dietary specializations among vertebrates. Ants are an important food resource for many lizard species. Here, we use a large dataset on ant consumption by lizards (345 species, 33 families) to explore evolutionary and ecological correlates of myrmecophagy across the evolutionary history of lizards. Based on literature and previous empirical work, we develop and test the following hypotheses about myrmecophagy: (i) it does not occur randomly across Squamata; it is correlated with (ii) foraging mode, (iii) habitat, (iv) body size, (v) aridity, and/or (vi) species range size. We found that ant ingestion is not distributed randomly in the phylogeny, with higher ingestion concentrated in some Iguania. Myrmecophagy also evolved in Lacertoidea and it is a derived trait with relatively recent origin. Foraging mode, habitat, body size, and aridity do not influence ant ingestion. Species with smaller range sizes show high variability in ant ingestion, whereas lizards with larger ranges tend to eat a lower proportion of ants. This result confirms the general ecological pattern that specialization is more common in narrowly distributed species. We suggest that future studies should also explore dietary specialization more broadly and provide a better taxonomic resolution of ant species in the diet of lizards. [ABSTRACT FROM AUTHOR]

Based on the latest molecular phylogenies of Gonyosoma sensu lato, which recovered five clades with robust support, we utilize morphological characters to demonstrate the distinctiveness of each clade, resulting in the resurrection of three genera (Gonyophis Boulenger, 1891; Rhynchophis Mocquard, 1897; and Rhadinophis Vogt, 1922) and a proposal of a new genus and a new tribe. A synopsis of the group, with descriptions and diagnoses, is provided for the five genera and eight species in addition to distribution maps and illustrations of the head of each taxon. An artificial key to the species and genera in the new tribe is presented in addition to the estimated origin times for each clade. [ABSTRACT FROM AUTHOR]

Paleoneurological studies of mosasaurids are few and limited to old partial reconstructions made from latex casts on Platecarpus and Clidastes. Here, the brain endocasts of three specimens of the early mosasaurid Tethysaurus nopcsai from the Turonian of Morocco are reconstructed for the first time by using micro-computed tomography. Comparisons between Tethysaurus and the later Platecarpus and Clidastes show that distinct endocranial organizations have occurred within the clade through time, including differences in the flexure of the endocast and the size of the parietal eye. The physiological consequences of such variability remain unclear and further investigations are required to better interpret these variations. In addition, the endocast of Tethysaurus was compared to those of extant anguimorphs, iguanians, and snakes, using landmark-based geometric morphometrics. The results revealed that Tethysaurus exhibits a unique combination of endocranial features compared to extant toxicoferans. Contrary to previous statements, we find no strong resemblance in endocast morphology between Tethysaurus and varanids. Rather, the endocast of Tethysaurus shows some morphological similarities with each of the clades of anguimorphs, iguanians, and snakes. In this context, while a notable phylogenetic signal is observed in the variability of squamate endocasts, it is premature to establish any phylogenetic affinities between mosasaurids and extant squamates based solely on endocast morphologies. [ABSTRACT FROM AUTHOR]

A breeding colony of wild-origin eastern indigo snakes (EISs, Drymarchon couperi) that is part of a reintroduction program has been impacted by gastric cryptosporidiosis. Gastric cryptosporidiosis is an insidious disease of squamates caused by an apicomplexan protozoan, Cryptosporidium serpentis. Viral coinfections have been implicated as possible immunosuppressant agents that allow for disease progression and both adenovirus and reovirus have been implicated in allowing for the progression of gastric cryptosporidiosis during coinfection in other snake species. Molecular (PCR) screening for adenoviruses and reoviruses was performed for both C. serpentis-positive and C. serpentis-negative EIS within the breeding colony. No reoviruses were detected in the collection. Adenoviruses were present in 11/68 (16.2%) EISs evaluated, and there was no significant difference between C. serpentis-positive and C. serpentis-negative EISs (p = 0.196). There was no significant difference in adenovirus status between C. serpentis-positive EISs' lifespan (p = 0.191) or survival rates (p = 0.823). These findings suggest that the presence of the adenoviruses found in this study does not contribute to the formation or progression of gastric cryptosporidiosis in EISs. [ABSTRACT FROM AUTHOR]

Predators with diverse diets can use generalized feeding behavior to consume different prey types or can alter behavior based upon the functional demands of each prey type. Prey choice and feeding behavior are especially important for limbless, gape‐limited predators, such as snakes, because the head must capture, subdue, and ingest prey. Although previous studies have described how snakes feed on dangerous prey, these studies have not compared how behaviors might vary with different prey types. We analyzed the feeding behavior of ground snakes (Sonora episcopa) that were fed scorpions, spiders, and centipedes. Ground snakes successfully consumed each prey type using different behaviors for each prey. To capture prey, snakes used the unusual behavior of pinning prey with the ventral surface of the head with a closed mouth strike before biting. Snakes grasped and envenomated scorpions in all trials, and this behavior lasted significantly longer for scorpions than for spiders. During envenomation, snakes used their body to pin the telson of the scorpion to reduce the likelihood of being stung. Rather than using body restraint to subdue spiders, the snakes often dragged spiders across the substrate with the mandible. Scorpions repeatedly pinched and stung snakes during feeding and snakes used body restraint to subdue this prey significantly more often than spiders. Our study revealed that ground snakes alter feeding behavior based upon prey defenses and use novel prey capture and handling behaviors to subdue prey, suggesting there is yet unappreciated diversity of feeding behavior in snakes allowing them to exploit dangerous arthropod prey. [ABSTRACT FROM AUTHOR]

The Calotes genus presents a challenge due to the complexity of its species. However, research on the cryptic species complex within the Indonesian Calotes genus is still lacking. This study aims to determine the extent of genetic relationships and assess the potential existence of a species complex within the Indonesian genus Calotes (Daudin, 1802) (Squamata, Agamidae) using the partial Cytochrome c Oxidase Subunit 1 (COI) gene sequence as a molecular marker. Samples of the Indonesian Calotes genus in this study were collected from South Lampung (Lampung), Bogor (West Java), and Langkat (North Sumatra). By aligning 582 bp sequence similarities with reference sequences in GenBank, we confirmed that seven out of eight samples analyzed belonged to Calotes vultuosus, while one sample was identified as Calotes versicolor. The identity values ranged from 96 to 100%. The C. vultuosus samples in this study displayed lower genetic distances, ranging from 0 to 3%, with the reference C. vultuosus sequence from Indonesia compared to the reference sequence from India, which ranged from 6 to 9%. Phylogenetic tree reconstruction, utilizing both maximum likelihood with IQ-Tree and Bayesian Inference with BEAST methods, further supports these findings. It reveals distinct groupings between C. vultuosus samples from Indonesia and India. These results suggest the potential occurrence of a species complex within the Indonesian genus Calotes. Furthermore, the inclusion of eight COI gene sequences from two Calotes species in the GenBank database has the potential to confirm the existence of previously undocumented species in Indonesia. [ABSTRACT FROM AUTHOR]

We present genome assemblies for 18 snake species representing 18 families (Serpentes: Caenophidia): Acrochordus granulatus , Aparallactus werneri , Boaedon fuliginosus , Calamaria suluensis , Cerberus rynchops , Grayia smithii , Imantodes cenchoa , Mimophis mahfalensis , Oxyrhabdium leporinum , Pareas carinatus , Psammodynastes pulverulentus , Pseudoxenodon macrops , Pseudoxyrhopus heterurus , Sibynophis collaris , Stegonotus admiraltiensis , Toxicocalamus goodenoughensis , Trimeresurus albolabris , and Tropidonophis doriae. From these new genome assemblies, we extracted thousands of loci commonly used in systematic and phylogenomic studies on snakes, including target-capture datasets composed of ultraconserved elements (UCEs) and anchored hybrid enriched loci (AHEs), as well as traditional Sanger loci. Phylogenies inferred from the two target-capture loci datasets were identical with each other and strongly congruent with previously published snake phylogenies. To show the additional utility of these non-model genomes for investigative evolutionary research, we mined the genome assemblies of two New Guinea island endemics in our dataset (S. admiraltiensis and T. doriae) for the ATP1a3 gene, a thoroughly researched indicator of resistance to toad toxin ingestion by squamates. We find that both these snakes possess the genotype for toad toxin resistance despite their endemism to New Guinea, a region absent of any toads until the human-mediated introduction of Cane Toads in the 1930s. These species possess identical substitutions that suggest the same bufotoxin resistance as their Australian congenerics (Stegonotus australis and Tropidonophis mairii) which forage on invasive Cane Toads. Herein, we show the utility of short-read high-coverage genomes, as well as improving the deficit of available squamate genomes with associated voucher specimens. [ABSTRACT FROM AUTHOR]

Polychaete worms of the genus Scolelepis are one of the most abundant members of beach ecosystems worldwide. Along the Atlantic coast of North America, specimens of Scolelepis inhabiting high-energy beaches have long been erroneously identified as the European species Scolelepis squamata (O.F. Müller, 1806). In this study, we examined specimens of Scolelepis collected from Massachusetts to Virginia, finding they match Scolelepis agilis (Verrill, 1873), originally described from beaches in New Jersey. Scolelepis agilis can be most easily distinguished from S. squamata based on differences in palp ciliary pattern, morphology of neuropodial lamellae, and the quantity and start of both notopodial and neuropodial hooded hooks. Live specimens of S. agilis collected from New York were also examined to provide data on their reproduction and morphometric analyses. In addition, molecular data (18S, 28S rRNA, cytochrome c oxidase I and 16S rRNA) showed that specimens of S. agilis from the north to mid-Atlantic coast formed a monophyletic group (p-distance ≤ 0.004 for MA, RI, NY and VA populations) and were distinct from S. squamata (p-distance ≥ 0.196 (0.03 SE)). The molecular data also suggest the presence of several misidentified or undescribed species of Scolelepis, highlighting the need for additional taxonomic work on the genus from these localities as well as others (e.g. South Africa) where the worms have been incorrectly identified as S. squamata. A key to species of Scolelepis from the east coast of the United States is provided and a lectotype and paralectotypes for S. agilis are herein designated. [ABSTRACT FROM AUTHOR]

Geckos stand out among lizards for communicating by means of visual, chemical, and acoustic modalities. Although these lizards are known for using these three modalities, the number of studies using them as subjects is restricted, especially those focused on the Chilean endemic genus Garthia. Here, we quantify the social behaviour of G. gaudichaudii, with special focus on the acoustic component. We also examine behaviours linked to the use of visual and chemoreceptive signals, and how these relate to acoustic signals, shedding light on the potential use of multichannel communication in this species. We examined social interactions of these lizards during encounters between pairs of non-breeding adult individuals of same or different sex. We found that both sexes emit single chirp calls of low intensity and at a low rate. Females calls preceded the approach of an interacting individual (male or female), while a single male called exclusively while ramming a female. We suggest an intimidatory functional role for these calls. Geckos also performed different visual displays, among which aggressive vertical tail-waving is followed by aggressive single chirp calls. Both sexes performed tongue-flicks, mainly to the air or to a conspecific, suggesting that vomerolfaction of volatile and non-volatile chemicals is important for chemical communication in this species. Some males performed courtship behaviours, but no copulation was recorded. Females rejected males performing tail-waving displays and made escape attempts, likely because experiments involved non-breeding subjects. Our study demonstrated that female and male G. gaudichaudii use acoustic signals coupled to various visual and chemoreceptive behaviours during social interactions. [ABSTRACT FROM AUTHOR]

Background Hypothesis/Objectives Animals Materials and Methods Results Conclusions and Clinical Relevance 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.To describe the clinical features and surgical outcomes of SCCs and BCCs diagnosed between 2010 and 2022 in reptiles.Thirty‐three captive reptiles (21 squamates and 12 chelonians).Detailed clinical history, including staging and surgical outcomes, were performed. Statistical analysis assessed significant factors using Prism (v8.2.1).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.This study contributes to predicting the clinical behaviour and prognosis of distinct SCC and BCC histological variants, and selecting the most appropriate treatment protocol. [ABSTRACT FROM AUTHOR]

Social animals need to keep track of other individuals in their group to be able to adjust their behaviour accordingly and facilitate group cohesion. This recognition ability varies across species and is influenced by cognitive capacities such as learning and memory. In reptiles, particularly Squamates (lizards, snakes, and worm lizards), chemical communication is pivotal for territoriality, reproduction, and other social interactions. However, the cognitive processes underlying these social interactions remain understudied. In our study, we examined the ability of male and female Tokay geckos (Gekko gecko) to chemically differentiate familiar and unfamiliar mating partners. Our findings suggest that both sexes can make this distinction, with males responding more to the odour of a familiar mate, and females responding more to unfamiliar mates. The lizards maintained their discriminatory abilities for two to three weeks but not up to six weeks after separation. This research highlights the efficacy of using odours as social stimuli for investigating social cognition in lizards, a promising avenue to better understand social cognition in these animals. [ABSTRACT FROM AUTHOR]

The type specimens of Scincella boettgeri (Van Denburgh, 1912) are mainly registered at the California Academy of Sciences, with a few of them now being registered at other institutions. Herein, we report a paratype specimen, previously exchanged with Kyoto University, now held at the National Science Museum, Tokyo. We compared the morphology of the specimen to the original description and here provide data on its morphological characteristics as well as photographs of the specimen. [ABSTRACT FROM AUTHOR]

The introduced Japanese weasel, Mustela itatsi, has had a significant negative impact on indigenous terrestrial vertebrates across several islands in the Miyako Group. The present study aimed to assess the current population status of squamate reptiles by investigating the distributions and abundances of three endangered lizards, Plestiodon kishinouyei, Takydromus toyamai, and Emoia atrocostata atrocostata, on Shimojijima Island and Irabujima Island. Route censuses for these species were conducted in the periods from 30 July to 4 August and 8–13 October 2022. Additionally, opportunistic sightings of lizards outside of the designated censuses were recorded. Eight P. kishinouyei, 20 T. toyamai, and seven E. a. atrocostata were recorded along four out of 101 survey routes, six out of 76, and two out of 39, respectively, with one additional E. a. atrocostata sighting at a non-census site. Plestiodon kishinouyei and E. a. atrocostata exhibited highly restricted distribution: the former was exclusively found in the northwestern part of Shimojijima Island, whereas the latter was confined to the southwestern part, with no presence on Irabujima Island. Takydromus toyamai was observed on both Shimojijima Island and Irabujima Island. The frequency of occurrence was low for the two skink populations on Shimojijima Island and T. toyamai on Irabujima Island, suggesting a potential population decline. These findings provide baseline data on the population status of these three lizard species. Such data will be crucial for evaluating their prospects for recovery, particularly considering the ongoing extensive eradication project targeting the introduced Japanese weasel on these islands. [ABSTRACT FROM AUTHOR]

The microstructure of the tuberculate dorsal and lamellar ventral skin of the body in rock lizards of different ages (Darevskia raddei, D. nairensis, D. valentini, D. dahli, and D. armeniaca) was described for the first time. The thickness of the skin in the most xerophilic species (D. raddei) is less than that in the more hygrophilic species. Rock lizards have single or paired longitudinal skin folds that are not closed from the side, which stretch along the inner side of the scutes to the distal edge. Small folds are also present in the lining of the squamous pocket; they consist of all layers of the skin and subcutaneous tissue. A large fold can completely block the cavity of the squamous pocket, the volume of which changes with contraction of the subcutaneous muscle bundles reaching the bases of the scutes. Small folds are also present on the scales of tuberculate skin. In mesophilic lizards (Zootoca vivipara), similar formations appear at later stages of postnatal ontogenesis than in rock lizards. The likely functional significance of the described skin structures is discussed. [ABSTRACT FROM AUTHOR]

The taxonomy of many Hemidactylus geckos from the Horn of Africa has recently been evaluated. However, the lack of fresh material for some species and also regions has led to the misidentification of some taxa and an underestimation of the true diversity in others. In this study we analyse new material of Hemidactylus collected from poorly known coastal areas of northern Somaliland. Our results support the existence of two yet undescribed species within the arid clade. One of the new species is small-sized and closely related to H. afarensis from the Afar Triangle in Ethiopia, and together with two other species (H. foudaii, H. sinaitus) forms the monophyletic group for which we propose here the name sinaitus species group. The other new species is medium to large-sized, known from only one locality, and belongs to the macropholis species group, where it is a sister species of H. macropholis. Both new endemic species from the northern coastal hyper-arid plains highlight the role of northern Somaliland as an important biodiversity hotspot. Furthermore, our results show pronounced genetic diversity within H. macropholis, and imply possible existence of cryptic taxa within the species. Hemidactylus arnoldi and H. tropidolepis have, for the first time, been sequenced and placed in a phylogenetic context in this study. Our results confirm that H. tropidolepis is nested within the African radiation and is most closely related to H. funaiolii. Hemidactylus arnoldi clustered within the Arabian radiation of Hemidactylus and it was recovered as a sister lineage to all other species of the radiation. [ABSTRACT FROM AUTHOR]

Morphological variation along the spatial distribution of species has been extensively investigated in ecological studies, and several ecogeographical rules explore the relationships between morphological traits and the environment. Many morphological traits are correlated, providing an opportunity to evaluate the validity of multiple ecogeographical rules simultaneously. Bergmann's rule predicts that endothermic animals in colder locations are larger than those in warmer locations. Jordan's rule predicts that fish from colder locations have more vertebrae than those from warmer locations. We tested the validity of Bergmann's and Jordan's rules for the neotropical lancehead snake Bothrops jararaca. We evaluated three morphological characters of 342 specimens: number of ventral scales (proxy for vertebrae number), snout–vent length (a linear measure of body size) and stoutness (volumetric body size). We implemented spatial regressions to evaluate the variation of morphological dimensions using climatic predictors: the minimum temperature and evapotranspiration. SVL was poorly related to minimum temperature and evapotranspiration. However, stouter individuals were found in colder places with greater evapotranspiration, following Bergmann's rule and the water conservation hypothesis. Individuals in warmer locations also had a greater number of ventral scales, reversing Jordan's rule. We showed that different selective pressures act on different morphological dimensions. Although stoutness follows Bergmann's rule, its variation would arise from an energy storage demand rather than heat conservation. Also, stoutness variation along evapotranspiration gradients could represent a mechanism to avoid hydric stress in environments with considerable climatic variations. The variation in vertebrae number along temperature gradients could be related to ecological factors and foraging. We highlight that physioecological mechanisms to deal with climatic variation and ecological aspects could be identified in snakes through intraspecific analyses, contrasting with interspecific studies that can hardly detect general trends. Due to different environmental effects on body size, we shed new light on the importance of exploring multiple morphological dimensions in macroecological studies. [ABSTRACT FROM AUTHOR]

Transposable elements (TEs) are repetitive DNA sequences which create mutations and generate genetic diversity across the tree of life. In amniote vertebrates, TEs have been mainly studied in mammals and birds, whose genomes generally display low TE diversity. Squamates (Order Squamata; including ∼11,000 extant species of lizards and snakes) show as much variation in TE abundance and activity as they do in species and phenotypes. Despite this high TE activity, squamate genomes are remarkably uniform in size. We hypothesize that novel, lineage-specific genome dynamics have evolved over the course of squamate evolution. To understand the interplay between TEs and host genomes, we analyzed the evolutionary history of the chicken repeat 1 (CR1) retrotransposon, a TE family found in most tetrapod genomes which is the dominant TE in most reptiles. We compared 113 squamate genomes to the genomes of turtles, crocodilians, and birds and used ancestral state reconstruction to identify shifts in the rate of CR1 copy number evolution across reptiles. We analyzed the repeat landscapes of CR1 in squamate genomes and determined that shifts in the rate of CR1 copy number evolution are associated with lineage-specific variation in CR1 activity. We then used phylogenetic reconstruction of CR1 subfamilies across amniotes to reveal both recent and ancient CR1 subclades across the squamate tree of life. The patterns of CR1 evolution in squamates contrast other amniotes, suggesting key differences in how TEs interact with different host genomes and at different points across evolutionary history. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Here we report on anguimorph lizards from the earliest Eocene (MP 7) of the Dormaal locality in Belgium, from the time of the warmest global climate of the past 66 million years. Several clades can be identified in this site: Glyptosauridae, Varanidae, and Palaeovaranidae. Our study focuses on glyptosaurid specimens previously reported from the site, some of which had been provisionally described as a new species,? Placosaurus ragei , and some assigned to an unnamed Placosauriops -like 'melanosaurine'. Our study presents data on new material, including an almost complete glyptosaurine frontal that has enabled us to assign much of the previously described material to a single genus and species. The specimens that had been assigned to both ? P ragei and the 'melanosaurine' share apomorphies (flat osteoderms and chevron-shaped osteoderms) with Gaultia , a glyptosaurid previously known from the earliest Eocene of Wyoming, USA. The Dormaal material represents the first record of this genus outside North America. In fact, the only potential evidence of the occurrence of 'Melanosaurinae' in Dormaal might be a single isolated vertebra described here. Here we also describe previously unfigured material of Saniwa and palaeovaranids from Dormaal. The presence of previously reported helodermatids cannot be supported in this Belgian site. [ABSTRACT FROM AUTHOR]

Morphological patterns may vary spatially in response to adaptations to regional environmental conditions. In fossorial animals, edaphic gradients potentially predict intra and interspecific morphological variation because they can limit dispersal and select morphotypes. We measured morphological traits of South American worm lizards, including three Amphisbaena and two Leposternon species, to test whether inter- and intraspecific morphological variation and morphotype distribution are predicted by edaphic gradients measured at different soil profiles. Interspecifically, we found that the variation in head length is mainly predicted by the chemical edaphic structure, which can be explained by spatial variation in prey availability. The variation in the width of the prefrontal and frontal shields was mainly predicted by clay and sand-soil contents, which can be explained by relationships of force and friction associated with digging. Intraspecifically, we found that the effects of edaphic gradients on morphological variation reflects the level of specialization to dig, since the most adapted species were mainly affected by variables measured in deeper soil profiles. We also show that soil-mediated intraspecific morphological variation shape morphotype distribution across different biomes that form the South American dry diagonal, which are discussed in light of biological, ecological, and biogeographic premises. [ABSTRACT FROM AUTHOR]

Abstract We here describe abundant new fossil material of amphibians and reptiles from different late Neogene localities of northern Greece: the Early Pliocene (MN 14) of Spilia 0, Spilia 1, and Spilia 2; the Early Pliocene (MN 15) of Spilia 3, Spilia 4, Spilia 5, and Vevi; and the Late Miocene or Pliocene of Chalicorrema and Rema Marmara. These new late Neogene herpetofaunas are highly diverse, documenting a considerably rich herpetofauna allowing the identification of at least two salamander, seven frog, two turtle, seven lizard, and eight snake taxa. Salamanders are represented by the salamandrid genera Ommatotriton and Ichthyosaura. Frogs are represented by the bombinatorid Bombina, the discoglossids Latonia cf. ragei and Latonia sp., the pelobatid Pelobates aff. praefuscus and Pelobates sp., the ranids Pelophylax and Rana cf. dalmatina, the hylid Hyla gr. arborea, and the bufonid Bufotes gr. viridis. Turtles are represented by the emydid Emys and an indeterminate geoemydid. Lizards are represented by the scincid Ophiomorus, two lacertids (one of which potentially pertaining to Lacerta), amphisbaenians, agamids, the anguid Pseudopus, and a potential varanid. Snakes are represented by the erycid Eryx, the natricid Natrix aff. rudabanyaensis, a small-sized elapid, an “Oriental viper”, the colubriforms Periergophis and Paraxenophis, as well as two further distinct but still indeterminate morphotypes of colubriforms. For the material from Spilia tentatively referred to Ommatotriton, this is only the third occurrence in the fossil record globally. The new material of Ichthyosaura and Bombina mark the first documentation of these genera in the Greek fossil record. Abundant cranial and postcranial material from Spilia is tentatively referred to Latonia ragei, a taxon previously known from the Early Miocene of Western Europe. The new record of Pelobates represents the oldest documented occurrences of the genus in the Greek fossil record. Interestingly, the Pelobates from Spilia bears much resemblance to an extinct taxon, Pelobates aff. praefuscus, which is otherwise known from the Late Miocene of the Caucasus, and not to the extant species that currently inhabits the area. The identification of Pelophylax and Rana adds to the rather poor Neogene record of ranids from Greece. Particularly for the case of Rana cf. dalmatina from Spilia 4, this corresponds to the only documented occurrence of this extant taxon in the Greek fossil record. Similarly, the identification of Hyla gr. arborea in Spilia 1, Spilia 3, and Spilia 4, marks only the third documented occurrence of this genus in the Greek fossil record. The Bufotes material from Spilia 1, Spilia 3, and Spilia 4 represents the first documented fossil occurrence of the extant Bufotes viridis complex in Greece. The material of Emys gr. orbicularis from Vevi marks the only known pre-Quaternary record of the genus in Greece and one of the only few Neogene members of the genus known from Europe. The scincid Ophiomorus is identified in Spilia 4, known from several cranial and postcranial remains, well outside the extant range of the genus. Practically, the Spilia Ophiomorus is only the fourth known fossil occurrence of this extant genus globally and also represents one of its oldest known occurrences. Material from Spilia 1 and Spilia 3 is tentatively referred to cf. Lacerta sp., and this would mark the first known occurrence of this emblematic extant genus in the Greek fossil record, denoting the presence of the genus since at least the Early Pliocene. The new amphisbaenian specimens from Spilia 4 add to the recently described single vertebra from the same locality, and represent the youngest occurrence of amphisbaenians from continental Eastern Europe. The new agamid material from Vevi and Chalicorrema add substantially to the record of this group, which was in Greece so far known exclusively from the latest Miocene/earliest Pliocene of Maramena. A similarly important addition is the record of Pseudopus from Spilia 4, as this genus had been known in the Greek fossil record only from a very few localities. The potential varanid from Spilia represents one of the few Pliocene occurrences of this group in Europe. We identify Natrix aff. rudabanyaensis among the material from Spilia 0, Spilia 4, and Vevi, adding to the previously known record of this taxon from Maramena, however, its precise species level assignment should await a revision of Neogene European Natrix spp. The find of a small elapid from Spilia 4 represents the youngest occurrence of a coral snake from Europe, extending their statigraphic range up to the Early Pliocene (MN 14). Periergophis and Paraxenophis, two bizarre snakes, so far exclusively known from their type locality in Maramena, could be also present here, even if tentatively identified. Most notably, the new material from these localities comprises forms that are now extinct (e.g., Periergophis and Paraxenophis) or extirpated from Europe (e.g., Latonia, Varanidae, Elapidae) but at the same time also loudly attests the emergence of the extant genera that dominate the extant herpetofaunas of Greece (Ichthyosaura, Bombina, Pelobates, Pelophylax, Rana, Hyla, Bufotes, Emys, Ophiomorus, Lacerta, Pseudopus, Eryx, and Natrix), for some of which their fossil record is documented here for the first time in the area.

Spiny lizards (genus Sceloporus) have long served as important systems for studies of behavior, thermal physiology, dietary ecology, vector biology, speciation, and biogeography. The western fence lizard, Sceloporus occidentalis, is found across most of the major biogeographical regions in the western United States and northern Baja California, Mexico, inhabiting a wide range of habitats, from grassland to chaparral to open woodlands. As small ectotherms, Sceloporus lizards are particularly vulnerable to climate change, and S. occidentalis has also become an important system for studying the impacts of land use change and urbanization on small vertebrates. Here, we report a new reference genome assembly for S. occidentalis, as part of the California Conservation Genomics Project (CCGP). Consistent with the reference genomics strategy of the CCGP, we used Pacific Biosciences HiFi long reads and Hi-C chromatin-proximity sequencing technology to produce a de novo assembled genome. The assembly comprises a total of 608 scaffolds spanning 2,856 Mb, has a contig N50 of 18.9 Mb, a scaffold N50 of 98.4 Mb, and BUSCO completeness score of 98.1% based on the tetrapod gene set. This reference genome will be valuable for understanding ecological and evolutionary dynamics in S. occidentalis, the species status of the California endemic island fence lizard (S. becki), and the spectacular radiation of Sceloporus lizards.

Thanks to their exceptional diversity, teeth are among the most distinctive features of vertebrates. Parameters such as tooth size, shape, number, identity, and implantation can have substantial implications for the ecology and certain social behaviors of toothed species. Despite decades of research primarily focused on mammalian dentition, particularly using the laboratory mouse model, squamate reptiles ("lizards" and snakes) offer a wide array of tooth types and dentition variations. This diversity, which includes differences in size, shape, function, and replacement capacity, provides invaluable opportunities for investigating these fundamental properties. The central bearded dragon (Pogona vitticeps), a popular pet species with well-established husbandry practices, is of particular interest. It features a broad spectrum of morphs and spontaneous mutants and exhibits a wide range of heterodont phenotypes, including variation in the size, shape, number, implantation, and renewal of teeth at both posterior and anterior positions. These characteristics position the species as a crucial model organism for developmental studies in tooth research and for gaining deeper insights into evolutionary patterns of vertebrate dentitions. In this article, we provide an overview of the current understanding of squamate dentition, its diversity, development, and replacement. Furthermore, we discuss the significant advantages offered by squamate species as model organisms for investigating the evolutionary and developmental aspects of vertebrate dentition. [Display omitted] • Teeth are a hallmark features of vertebrates • Large ecomorphological diversity of squamate dentitions remains largely unexplored • Central bearded dragon is an emerging model for evo-devo and dental research • Squamate dentition: diversity, development, and replacement importance • Squamate models offer crucial insights into vertebrate tooth evolution [ABSTRACT FROM AUTHOR]

Lizard species of wide distribution can show differences in morphology and many other characteristics, in particular in the scutelation. In this study, we analyzed the variation of 22 meristic characters between sexes and among populations of Sceloporus variabilis from the state of Hidalgo in central Mexico. The variables such as dorsal scales, scales around the body, ventral scales, femoral pores, interfemoral scales, and lamellae of the fourth digit of the hindlimbs were different among populations; the population of San Pablo Tetlapayac presented the highest average values in these variables. A positive and significant relationship between snout–vent length and the number of ventral scales was found only in the females of San Pablo Tetlapayac and Santa Catarina. The variations recorded in the present study indicate an effect of environmental variation in the pattern of the number of scales, and suggest that both environmental conditions, such as precipitation and temperature, and ecological conditions, such as substrate or microhabitats, may be influencing differences in the number and size of scales among populations. Further studies on physiology and ecomorphology are necessary to determine the direction of variations in scutelation between sexes and populations. [ABSTRACT FROM AUTHOR]

We describe two new small-bodied species of South Asian Cnemaspis from Kanyakumari District of Tamil Nadu State, India. The two new species are sister taxa, forming a well-supported, previously unsampled clade of South Asian Cnemaspis that we name the kanyakumariensis clade. This new clade is recovered with weak support as the sister taxon to the goaensis clade. Both the new species together can be easily distinguished from all other peninsular Indian clades by a combination of non-overlapping morphological characters such as small size with snout to vent length < 40 mm, femoral pores only present in males, presence of spine-like tubercles on flanks, and condition of the subcaudals. They can also be distinguished from each other by several characters such as the number of dorsal tubercles around the body, short vs long spine-like tubercles on flank, and the arrangement of keeled subcaudal scales. They also differ by uncorrected pairwise sequence divergence of 10.2 and 2.9% for ND2 and 16S, respectively. This work reveals that even the low-elevation coastal hills of southern India have ancient, endemic lineages and require protection. [ABSTRACT FROM AUTHOR]

Translocation is one strategy to reestablish populations of scaled quail (Callipepla squamata). Initial reproductive success post‐translocation is important for establishing short‐lived species such as quail, but factors influencing reproductive success are poorly understood. We evaluated the effect of source population and variation in delayed release strategy (1−9 weeks) on nest initiation and nest survival of wild‐caught, translocated scaled quail. We trapped and translocated scaled quail in 2016–2017 from source populations in the Edwards Plateau and Rolling Plains ecoregions of Texas, USA, to a large contiguous (>40,000 ha) release site in Knox County, Texas. We used a multi‐state mark‐recapture model with state uncertainty to test for effects of release treatment, source population, age, release location, and year on nest initiation and survival. Increased length of holding time decreased re‐nesting effort. Yearlings were more likely to initiate nests than adults and the probability of re‐nesting was lower during the year with drought conditions. There was no effect of source population on any of the parameters we evaluated. Future scaled quail reintroduction efforts may benefit from prioritizing translocation of yearlings and conducting translocations when drought conditions are not forecasted. [ABSTRACT FROM AUTHOR]

The palaeofauna of the Quaternary is mostly known from the mammals' record, while the herpetofauna is less represented. In the same way, in northeastern Argentina reptile fossils records are scarce, usually represented by preliminary communications. This paper focuses on the study of herpetofauna remains from the Isla El Disparito archaeological site. The faunal materials collected at the site revealed an increase in taxonomic diversity related to the Quaternary herpetofauna in the IED site, with over 50% of the bone remains represented by anurans and at least six recognized squamates taxa. The purpose of this study is to properly identify these new records of herpetofauna remains from northeastern Argentina during the Holocene as well as to provide a dichotomous key of postcranial remains for identifying extant squamates taxa in other Quaternary sites from Argentina. The identified squamate assemblage includes the lizard Ophiodes sp., the snake families Typhlopidae, Dipsadidae, Viperidae and undetermined colubroids, along with anuran bone remains (Anura indet. and ?Hylidae). Additionally, the findings contribute to a better understanding of the herpetological assemblage in Argentina, providing insights into the composition of South American squamates during the Quaternary. [ABSTRACT FROM AUTHOR]

In the Anthropocene, the ranges of introduced species are expanding, while extinction‐prone species are contracting. Introductions and extinctions are caused by how species respond to human impacts, but it is unknown why the ranges of some species expand and some contract. Here, we test whether this opposite response of human impact is due to introduced and extinction‐prone species falling at opposite ends of geographic, evolutionary, or ecological trait continua. We constructed a database of native range maps, traits, phylogenetic relationships, and the introduction and extinction‐prone status of squamate reptiles with ranges native to the Western Hemisphere. Across > 3000 snake and lizard species (88% of known native squamates), 142 had been introduced elsewhere and 483 were extinction‐prone (i.e. vulnerable, endangered, critically endangered, extinct in the wild, extinct). To explain variation in status, we first tested if the same human‐impacted regions in the Americas contained the native ranges of species of either status. Second, we tested for phylogenetic signal in species status. Finally, we tested the explanatory power of multiple trait continua. The native ranges of introduced and extinction‐prone reptiles were clustered in island regions with high human impact versus mainland regions with lower human impact. Phylogenetic signal was weak for status, but introduced and extinction‐prone species were clustered in different clades. All geographic and ecological traits that explained each status supported the opposite ends hypothesis. Introduced species had larger, edgier ranges, while extinction‐prone species had smaller, simpler ranges. Introduced species were mostly herbivorous/omnivorous, while extinction‐prone species were mostly carnivorous. Introduced species produced larger clutches, while extinction‐prone species had smaller body sizes. In the Anthropocene, the native ranges of introduced and extinction‐prone species are in the same human‐impacted regions where trait continua, having opposite effects, determine whether species ranges expand or contract in the continuing face of global change. [ABSTRACT FROM AUTHOR]

Land-use change is a main threat to biodiversity due to its impact on habitats, especially for species that inhabit mountainous regions. In the face of this, an adequate management requires knowledge of species habitat requirements, but in Chile, few studies have analyzed these requirements in a vulnerable group like reptiles in anthropized environments. A situation relevant to this problem is the Andes of Chile, which are facing increasing levels of anthropization that could affect species such as Liolaemus nigroviridis, a lizard that inhabits areas where urbanization, skiing, livestock, and waste have been increasing. However, there is no available information on the impact of these activities on this species. To analyze the effect of anthropization on L. nigroviridis, a study of habitat use with anthropogenic and natural resources was carried out through the analysis of resource selection indices (in Farellones, central Chile). Our results show that L. nigroviridis is affected by constructions; above a threshold of 15% of built environment, the species is not present. However, small-scale livestock, waste, and roads showed no apparent effects on the species. We concluded that urbanization is one of the main threats to this lizard in Farellones, since it is a determining factor for its presence. [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]

Squamata is one of the groups of sauropsids with the greatest diversity in life histories. The timing and expression of events related to reproductive phenology are considered among the most important components of squamate life histories. Here we studied the male and female reproductive patterns, clutch size, and clutch frequency of the oviparous lizard Sceloporus aeneus from a population in the southeast of Hidalgo State, Mexico, from April 2010 to March 2011. The gonadal analysis showed that the minimum snout-vent length at sexual maturity in males and females was 46 mm. Both sexes exhibit seasonal reproductive patterns; males present maximum gonadal activity in winter-spring (February-May), and females are vitellogenic in spring-summer (May-July). Clutch size averaged 7 eggs (range 5-9) and did not show a relationship with female body size. Females produce at least two clutches per breeding season. The reproductive patterns described in this study were similar to those observed in other populations of S. aeneus, although some events in the reproductive phenology of both sexes appear to be related to local environmental factors. [ABSTRACT FROM AUTHOR]

Caudal autotomy is a behaviour in lizards that favours survival but brings with it some associated costs, mainly loss of energy, which is related to the position of the breaking point. Moreover, the frequency of tail loss can vary at different levels, between sexes, populations, seasons and at an intra-and inter-population level. In this study, we analysed the breaking position of the tails in individuals and frequencies of tail loss between years, sexes, seasons and populations of the lizard Sceloporus variabilis that inhabit contrasting environments. The results showed a low frequency of tail loss at the ends (distal and proximal) of this organ (except for individuals from the xeric scrubland population) and there was a higher proportion of complete than incomplete tails in lizards for all analysed populations. Also, there was no variation in the frequency of tail loss among populations, sexes (except in one population), years or seasons. A higher proportion of organisms with complete tails suggests that this organ is an important element for these lizards. In addition, the lack of variation in the frequency of tail loss may indicate a similar behaviour such as escape from predators among the groups analysed. [ABSTRACT FROM AUTHOR]

Exploitation of different locomotor substrates in different ecological niches has driven the evolution of specialized morphological structures, and similar ecological demands, such as the structure of the microhabitat, often lead to convergent or parallel evolution.The evolution of adhesive toepads in geckos remains understudied because of the paucity of phylogenetically‐informed investigations of candidate clades exhibiting purported incipient expression of these (i.e. species having evolved some, but not all, parts of the complex adhesive system of pad‐bearing geckos).Using Cyrtodactylus, a speciose genus with well‐established ecotypes, we tested the hypothesis that microhabitats that require more climbing will lead to the acquisition of incipient adhesive morphology.We measured subdigital scale area, a proxy for adhesive toepad evolution, and quantified subdigital scale shape for 77 of the 354 described species, including at least one representative of each ecotype.Subdigital scale area increased from terrestrial through generalist and saxicoline (rock‐dwelling) to arboreal ecotypes, with subdigital scale shape evolving from ancestral conditions for padless lizards to lateromedially expanded lamella‐like scales only in the arboreal ecotypes.This significant link between phenotype and environment supports the contention that scansorial, and particularly arboreal, Cyrtodactylus ecotypes have evolved incipiently expressed adhesive toepads. This highlights the suitability of this genus as a model system for studying the ecology and evolution of adhesive toepads as well as being a promising candidate for research on adaptive radiations. Read the free Plain Language Summary for this article on the Journal blog. [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]

We provide a detailed and first description of the skull, hyoid apparatus, and trachea of the Turks and Caicos rock iguana, Cyclura carinata (Squamata: Iguanidae). Cyclura is a radiation of iguanas restricted to islands of the Caribbean Sea. Species of Cyclura have high rates of endemism, and all species are severely threatened with extinction. Our anatomical description of this threatened iguana is based on high-resolution computed tomography scans of one adult, one putative adult or near adult, and one juvenile specimen, and includes three-dimensional segmented renderings and visualizations. We discuss some observations of intraspecific and ontogenetic variation, and provide a brief comparison with specimens of another species of Cyclura and published descriptions of other iguanas. Our study provides a cranial osteological framework for Cyclura and augments the body of knowledge on iguana anatomy generally. Finally, we posit that our description and future studies may facilitate identification of fossil Cyclura, which could help understand the paleobiogeography of the genus. [ABSTRACT FROM AUTHOR]

The Middle Eastern endemic genus Asaccus comprises Southwest Asian leaf-toed geckos. To date, this genus includes 19 species of leaf-toed geckos (seven in Arabia and 12 in the Zagros Mountains). Despite a recent study on the taxonomy and phylogeny of Asaccus species in Iran, controversies still remain surrounding the phylogeny and phylogeography of the genus. Here, we used an integrative approach to determine the phylogeny and phylogeography of Asaccus species using two mitochondrial genes (12 S and Cyt b), and one nuclear gene (c-mos). Our results uncovered 22 distinct lineages, demonstrating a significant cryptic diversity that challenges the current morphological classifications of these species. Phylogenetic analyses reinforce the monophyly of the Asaccus group, positioning A. montanus as a basal lineage, which supports a deep evolutionary divergence dating back to the Late Oligocene, approximately 27.94 million years ago. This genetic diversity also highlights the impact of historical climatic and geographical changes on species diversification. The findings advocate for an integrative approach combining both molecular and morphological data to resolve species identities accurately, thereby enhancing conservation strategies to protect these genetically distinct lineages. [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]

The family Acuariidae is a speciose group of parasitic nematodes, infecting mostly birds as definitive hosts. This study focused on the characterization of two species of acuariids, collected in two different species of piscivorous birds, the European great cormorant Phalacrocorax carbo sinensis from Italy, and the pygmy cormorant Microcarbo pygmaeus from Israel. Parasites were analyzed using light and scanning electron microscopy and by amplification and sequencing of the 28S rDNA. The results of morphological and molecular analyses showed that Ph. carbo sinensis was infected by the acuariid Syncuaria squamata (12 females) and Cosmocephalus obvelatus (1 female), whereas M. pygmaeus was infected by C. obvelatus (2 males, 12 females). The present results provide new data on the distribution of acuariid parasites of piscivorous birds, the first report of Acuariidae in Israel, and the first molecular data on S. squamata and C. obvelatus, which will be useful in future epidemiological and phylogenetic studies of these widely distributed, but less molecularly studied parasites. [ABSTRACT FROM AUTHOR]