Lizard Species Research Articles

Comparing Preferred Temperatures and Evaporative Water Loss Rates in Two Syntopic Populations of Lacertid Lizard Species

Many reptiles actively regulate their body temperature. During thermoregulation, they suffer evaporative water loss (EWL). Since evaporation increases with temperature, EWL could limit the activity of ectotherms when water is not available. In this study, we compared the preferred body temperatures (Tp) and EWL of two lacertid lizard species, Darevskia praticola and Podarcis muralis, at the western edge of D. praticola’s range, where they live in syntopy. We hypothesized that D. praticola, a species that inhabits forested and humid environments, would have a higher EWL than the more widespread P. muralis. Our results show that D. praticola prefers lower temperatures (mean Tp = 28.1 °C) than P. muralis (mean Tp = 30.6 °C). Despite the differences in their thermal preferences, both species showed similar total EWL (2.76% for D. praticola and 2.67% for P. muralis), although their daily patterns of water loss differed. Our results suggest that D. praticola has developed mechanisms to control water loss and that its lower thermal preference may be due to both historical factors and local adaptations. These results contribute to the understanding of how environmental factors influence the physiology of lizards, which in turn has implications for predicting the effects of climate change on species distribution.

Untangling the morphological and genetic variation of two endemic lizards from the coastal sand dunes of Northeastern Brazil

Abstract Studies in the Neotropical region consistently highlight high levels of endemism and biodiversity. However, challenges persist, particularly in uncovering the cryptic diversity among species. Various approaches are needed to address this, including morphological, genetic, and environmental data. This study focused on genetic and morphological variation in three endemic, sympatric lizard species: Tropidurus hygomi, Glaucomastix abaetensis, and Glaucomastix itabaianensis in the coastal sand dunes of Northeastern Brazil. These lizards are confined to sandy Pleistocene-formed environments with limited distribution. While earlier research revealed substantial genetic diversity, gaps remained in distribution sampling, morphological data, and understanding the correlation between this variation and environmental factors. We aimed to identify genetic clusters to assess the alignment of phenotypic differences with these clusters and explore potential relationships between climatic and geographical factors and morphometric variations. We utilized mtDNA data to assess population clusters. Geometric and linear morphometrics were employed to analyze morphological data, which was then correlated with climatic information. Results unveiled genetic and morphological variations signifying the presence of cryptic diversity. Our analyses also highlighted the influence of geography and climate on morphometric variations. These findings underscore hidden diversity and a complex evolutionary history within the confined Pleistocene sand dunes. Further genomic analyses could contribute to comprehending these patterns and enhancing the conservation strategies for these endangered species.

Reidentification of a 19th century specimen reveals the first record of Amphisbaena hogei Vanzolini, 1950 (Squamata, Amphisbaenidae) in Minas Gerais, Brazil

For almost 60 years, a specimen of Amphisbaena collected in the 19th century by the Danish zoologist Johannes Theodor Reinhardt in southeastern Brazil has been identified as Amphisbaena prunicolor. Here I present a reidentification of this specimen (NHMD R4448) as A. hogei, together with a review of known records of this small worm lizard species, endemic to Brazilian Atlantic Forest. This represents the first record of A. hogei for the state of Minas Gerais. Most known records of A. hogei are based on specimens collected more than half a century ago and urbanization could have led to local extinction in some localities, triggering an alert regarding its conservation status.

Age-dependent self- and individual chemosensory discrimination in male Psammodromus algirus lizards is based on lipids and proteins from their scent

Self- and individual discrimination are needed to maintain social relationships. However the extent of precision of these abilities may depend on the social strategy of each individual, which may vary with ontogeny. Many animals use chemical cues to discriminate conspecifics. For example, many lizards use femoral gland secretions, which are composed of lipids and proteins, but it is not well known the role of each of these chemical classes in conspecific discrimination. We examined whether and how differences in age-dependent social strategies of male lizards Psammodromus algirus affect self- and individual chemosensory discrimination, and whether these are mediated by the lipid and/or protein fraction of femoral secretions. In this lizard species, there are two age categories of males that adopt alternative reproductive strategies; dominant and territorial “old” males and “young”, but reproductively mature, satellite-sneaker males. We examined chemosensory responses to separated lipid and protein fractions of femoral secretions. Both young and old males discriminated both their own lipids and proteins from those of conspecific males of their same age category. With respect to individual discrimination, only old males distinguished different unfamiliar old males based on their lipids alone, but not on proteins, while they do not discriminate between different individual young males. In contrast, young males do not show individual discrimination in any case. Therefore, our results show age-related differences in chemical social discrimination abilities in male P. algirus lizards that could be explained by their different age-dependent social strategies.

Coexistence or extinction: Dynamics of multiple lizard species with competition, dispersal and intraguild predation.

Biological invasions significantly impact native ecosystems, altering ecological processes and community behaviors through predation and competition. The introduction of non-native species can lead to either coexistence or extinction within local habitats. Our research develops a lizard population model that integrates aspects of competition, intraguild predation, and the dispersal behavior of intraguild prey. We analyze the model to determine the existence and stability of various ecological equilibria, uncovering the potential for bistability under certain conditions. By employing the dispersal rate as a bifurcation parameter, we reveal complex bifurcation dynamics associated with the positive equilibrium. Additionally, we conduct a two-parameter bifurcation analysis to investigate the combined impact of dispersal and intraguild predation on ecological structures. Our findings indicate that intraguild predation not only influences the movement patterns of brown anoles but also plays a crucial role in sustaining the coexistence of different lizard species in diverse habitats.

Elevational Range Impacts Connectivity and Predicted Deme Sizes From Models of Habitat Suitability.

In integrative distributional, demographic and coalescent (iDDC) modelling, a critical component is the statistical relationship between habitat suitability and local population sizes. This study explores this relationship in two Enyalius lizard species from the Brazilian Atlantic Forest: the high-elevation E. iheringii and low-elevation E. catenatus and how this transformation affects spatiotemporal demographic inference. Most previous iDDC studies assumed a linear relationship, but this study hypothesises that the relationship may be nonlinear, especially for high-elevation species with broader environmental tolerances. We test two key hypotheses: (1) The habitat suitability to population size relationship is nonlinear for E. iheringii (high-elevation) and linear for E. catenatus (low-elevation); and (2) E. iheringii exhibits higher effective migration across populations than E. catenatus. Our findings provide clear support for hypothesis (2), but mixed support for hypothesis (1), with strong model support for a nonlinear transformation in the high-elevation E. iheringii and some (albeit weak) support for a nonlinear transformation also in E. catenatus. The iDDC models allow us to generate landscape-wide maps of predicted genetic diversity for both species, revealing that genetic diversity predictions for the high-elevation E. iheringii align with estimated patterns of historical range stability, whereas predictions for low-elevation E. catenatus are distinct from range-wide stability predictions. This research highlights the importance of accurately modelling the habitat suitability to population size relationship in iDDC studies, contributing to our understanding of species' demographic responses to environmental changes.

The Ultrastructure of Spermiogenesis Within the Seminiferous Epithelium of the Texas Horned Lizard, Phrynosoma cornutum (Phrynosomatidae).

Currently, there is limited histological data for spermatid morphologies within the testes of squamates. There are only 10 species of lizard that have complete ultrastructural data across the entire process of spermiogenesis, including several species of Sceloporus. These studies have shown that differences can be seen between spermatids of saurians within the same family or genus. Thus, the present study continues to test the hypothesis that differences exist in spermatid morphology between species within the same family. We collected five Phrynosoma cornutum males from Arizona. Their testes were extracted and processed with standard TEM techniques. Many of the characteristics of spermiogenesis within P. cornutum are conserved and similar in morphology to other phrynosomatid lizards. These similarities include the development of the acrosome, perforatorium, subacrosomal cone, nuclear rostrum, and epinuclear lucent zone. However, there were also differences observed in P. cornutum spermatids that are distinct compared to other phyrnosomatids. For example, P. cornutum spermatids include a wider and more robust perforatorium and less spiraling of the chromatin during condensation than that of other phrynosomatid lizards. The present results corroborate previous studies and indicate that even with morphological conservation within saurian spermatids, character differences between species can be recognized. Further studies on spermiogenesis are required to judge the relevance of these ontogenetic changes in terms of using them in amniotic or squamate spermatid/spermatozoa phylogenic analysis.

Reptiles as Experimental Models: Uncovering Their Role in Drug Development and Health Research

Experimental animal models are indispensable as they help to enhance the understanding of unknown diseases and contribute to new discoveries through their physiology, which facilitates the learning process and scientific dissemination. Consequently, the techniques applied to animal models require the development of guidelines that ensure respect for these animals and the reliability of the results obtained, in order to promote the advancement of scientific progress. With this in mind, the aim of the present study was to conduct a review on the use of reptiles as experimental models. The works were reviewed and selected based on their use of animals (reptiles) as experimental models and for having results relevant to the development of science and its various applications. In this context, analyzes that adhered to these principles were also considered, revealing that certain species of snakes, lizards, and turtles show promise for research in pharmaceuticals, the production of medicines and vaccines, as well as in seeking solutions to other problems related to animal health, for example, the study of baseline corticosterone (CORT) concentrations in rattlesnakes. Thus, we can conclude that, although these animals are not as commonly used in experimental research, reptiles hold an important position among vertebrates for investigating the progression of serious diseases, as well as for the development of vaccines and medications.

Potential distribution of endemic lizards from Brazilian restingas: The present announcing the end.

The restinga habitats are coastal psammophilous environments, with only 0.47% of the original area remaining in Brazil. This environment embraces at least 36 known species of lizards, 7 of them being endemic. Besides direct anthropogenic impacts, climate change raises new cautions on Brazilian restingas-endemic lizards conservation. We evaluated the current and future potential distribution of the endemic lizards from Brazilian restingas, considering different climate change scenarios. We hypothesized shifts in the potential distribution of the restinga-endemic lizards. We conducted ecological niche modeling to predict the potential distribution of Brazilian restingas-endemic lizards. Here, we used an ensemble of three modeling algorithms (Bioclim, GLM, and SVM). In predicting the effects of climate change on their future distributions, we used intermediate and pessimistic socio-economic pathway scenarios (SSP3 70 and SSP5 85, respectively) considering projections for 2081-2100. Furthermore, we calculate the extent of future potential distribution covered by the current spatial configuration of integral protection areas to assess if they will still be effective in conserving the species in the future. We did this by binarizing predicted potential distribution with a threshold of 0.8. Our data pointed out that the species will have their potential distribution area altered for 2081-2100, considering climate change scenarios. Tropidurus hygomi, Glaucomastix abaetensis, and G. itabaianensis overlapped along their predicted potential distribution for the present and future. The same was found to Ameivula nativo and Liolaemus lutzae. Moreover, our results showed a potential marked reduction of potential distribution covered PAs. The recognition of potential distribution areas discussed here enables focal and urgent conservation strategies, besides bringing up alerts on protected areas' role in conserving these species under climate change scenarios. We propose creating planning policies using space and time criteria and developing long-term studies, besides promoting educational programs aiming at environmental conservation. Thus, we expect our research to contribute to the protection of the land over Brazilian restingas-endemic lizards' distribution.

Evolutionary Links Between Skull Shape and Body Size Suggest Allometric Forces and Selection at Work in a Generalist Group of Lizards.

The vertebrate skull is a complex structure, and studies of skull shape have yielded considerable insight into the evolutionary forces shaping specialized phenotypes in organisms as diverse as bats, frogs, and fossorial animals. Here, we used phylogenetic comparative analyses of CT scans of male skulls from 57 species of Sceloporus lizards to explore patterns of skull evolution in a group of generalist taxa. We found that most interspecific variation is in terms of skull elongation such that some species have long, narrow skulls, whereas others exhibit more compact and robust skulls. We also found strong links to overall body size, with evolutionary shifts to larger bodies being associated with more compact skulls and slower evolutionary rates. This is the opposite of the pattern in most mammals in which larger bodied species have longer snouts, and more like the pattern in frogs in which function has played a more important evolutionary role. Also, unlike other vertebrates, the jaw, anterior, and posterior parts of the Sceloporus skull are largely integrated, having evolved independently of each other only to a limited, albeit significant, degree. Our results emphasize the importance of body size in the evolutionary shaping of the skull and suggest that additional studies of behavioral function in a generalist group are warranted.

The Okuru skink (Oligosoma carinacauda sp. nov) of South Westland, New Zealand-simply elusive or extinct?

A small brown, longitudinally striped skink from Okuru, South Westland, New Zealand is described as Oligosoma carinacauda sp. nov. It is distinguished from all congeners by the combination of three supraocular scales and a keeled tail. The species is known only from a single specimen, collected from sphagnum moss within supralittoral dune habitat at Mussel Point, Okuru in 2000. Follow-up targeted surveys undertaken since by expert herpetologists have failed to relocate the species to date. As it is known that many New Zealand lizard species face a perilously uncertain future due to anthropogenic-induced pressures such as habitat loss, predatory pests, and climate change, there are serious concerns for the survival of this species.

Not armoured enough: The black-and-white tegu Salvator merianae (Squamata: Teiidae) as a predator of armadillos (Cingulata)

Reporting predation events is crucial to understand how species behaviour and predator-prey interactions shape food webs. However, data is still lacking for most neotropical fauna, especially reptiles. Salvator merianae is a widespread lizard species, which is often found in human-altered habitats and has been introduced in multiple locations. This Neotropical lizard is omnivorous and acts as a necrophagous, seed disperser and predator of small-sized animals. However, in spite of extensive data on its generalist diet, detailed predation records over medium-sized vertebrates (between 1 and 40 kg) are scarce. Here we report the first records of S. merianae predation on three distinct armadillo species, all of which occurred in human-altered habitats in Brazil and Argentina. Our records contribute to a better understanding of trophic interactions in modified landscapes and how large reptiles, such as S. merianae, may play an important role in food webs in the absence of larger predators.

Skin morphology of five species of rock lizards of the genus Darevskia (Lacertidae, Squamata)

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, D. armeniaca) has been 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 scales to its 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 is able to completely block the cavity of the squamous pocket, the volume of which changes with the contraction of the subcutaneous muscle bundles reaching the bases of the scales. Small folds are also present on the scales of tuberous skin. In hygrophilic lizards (Zootoca vivipara), similar formations appear at later stages of postnatal ontogenesis than in rock lizards. The probable functional significance of the described skin structures is discussed.

Relationship between predation and maternal investment In Curly-Tailed Lizards

The Northern Curly-tailed Lizard (Leiocephalus carinatus armouri) is invasive in Florida, where it has establishedmultiple populations. Like most animals, the species faces various environmental pressures, including predation,which influences reproductive strategies. To test the hypothesis that a correlation exists between predation rates onfemales and offspring-resource allocation, we examined specimens from 11 populations in Florida, assuming that thosewith broken tails had encountered a potential predator. To quantify offspring-resource allocation, we used the numberof ovarian follicles in each female and the ratio of number to average size of the largest follicles. We predicted that thosetraits would differ between lizards with and without broken tails. We did not detect the expected correlation, suggestingthat predation pressure did not affect the number or size of follicles. Consistent with other lizard species, we did findthat larger body size was correlated with a greater number of follicles.

A Pleistocene Biogeography in Miniature: The Small‐Scale Evolutionary History of Podarcis lusitanicus (Squamata, Lacertidae)

ABSTRACTAimRecent literature is unveiling more complex responses of biodiversity to Pleistocenic climatic oscillations than those derived from initial models based solely on southern glacial macrorefugia. Here, we zoom in to delve into the genetic diversity and population structure of Podarcis lusitanicus, a lizard species native to the north‐western Iberian Peninsula.LocationNorth‐western Iberian Peninsula.TaxonPodarcis lusitanicus.MethodsUtilising a comprehensive multilocus approach, we explored the species' phylogeography and demographic history at a very fine spatial scale and timeframe. Concurrently, we evaluated both current and historical habitat suitability for the species, linking it to the observed demographic trends. We examined DNA sequences from two mitochondrial (cytb and ND4) and three nuclear genes (ACM4, MC1R and PDC) in 230 specimens collected from 21 populations spanning most of the species' distribution range.ResultsOur findings corroborate cytonuclear discordances in Podarcis, with nuclear genes failing to identify the mitochondrial clades in P. lusitanicus. Despite its separation from other Podarcis species approximately 4 million years ago, its diversification occurred much more recently, around 0.4 million years ago, resulting in three monophyletic lineages that are geographically coherent. This pattern suggests that some lineages of P. lusitanicus might have gone extinct after the split from the common ancestor. Pleistocene climatic oscillations profoundly influenced the demographic history of the species. During warmer periods, such as the Last Interglacial, populations expanded and came into secondary contact, whereas during the Last Glacial Maximum, populations contracted and became isolated in multiple micro‐refugia. The subsequent Mid‐Holocene warming facilitated population recovery, range expansion and lineage admixture.Main ConclusionsThis study underscores the intricate interplay between isolation and dispersal at a microscale, driven by Pleistocene climatic fluctuations, which have profoundly shaped the genetic structure and diversity of Iberian terrestrial biodiversity and may remain overlooked by biogeographic studies at coarser scales.

A comprehensive review of the ecology and conservation status of spot-tailed earless lizards (Holbrookia lacerata and Holbrookia subcaudalis)

Spot-tailed Earless Lizards (STEL; Plateau STEL, Holbrookia lacerata; and Tamaulipan STEL, Holbrookia subcaudalis) are lizard species that are in decline both in number and distribution. As a result, this species has been considered for federal threatened status and a 90-day finding by the United States Fish and Wildlife Service stated that federal protection may be warranted. To date, a decision for Endangered Species Act listing for the Plateau STEL has been denied, but a judgement for the Tamaulipan STEL has not yet been decided. The requests to list STEL as a threatened species initiated numerous studies to investigate the status of both species and to add to the knowledge base of STEL. Though many studies have been conducted, much of the resulting information exists in gray literature (e.g., governmental reports, project summaries, etc.) that are not readily available or peer-reviewed. Herein, we consolidate the research results from scientific literature, governmental reports, and petitions to assist future researchers of STEL. We describe the natural history of STEL, their current taxonomy, conservation status, and discuss potential causes for their decline. Our goal is to provide the needed background knowledge for future researchers and policy makers.

Helicobacter cappadocius sp. nov., from lizards: The first psychrotrophic Helicobacter species

It was aimed to determine the prevalence of Helicobacter in some reptilian and amphibian species in Türkiye and to describe the bacteria. For this purpose, 73 cloacal swab samples were used as material. The description of the isolates was performed by detailed phenotypic tests, whole genome analyses, and MALDI-TOF MS. As a result of the phenotypic analysis, two helical, curved Gram-negative, motile isolates were recovered. It was determined through the analysis of 16S rRNA gene sequences that two isolates belonged to the genus Helicobacter. These isolates were found to be in a distinct group from other Helicobacter species. However, the 16S rRNA sequence did not match any identified species, with the closest match being Helicobacter mustelae strain R85-13-6T, which had an identity level of 96.2 %. Additionally, it was found that strains faydin-H75T and faydin-H76 had a 99.3 % identity level for their 16S rRNA genes. After conducting dDDH and ANI analyses, it was found that strains faydin-H75T and their close neighbors H.anseris ATCC BAA-1299T shared 13.5 % and 68.8 % similarity, respectively. The genome size of the strains was 1.7 Mb while G + C contents were 33.5 %. Metagenomic analyses using IMNGS and Protologger tools revealed the presence of faydin-H75T in various lizard species with high similarity, confirming its broad distribution and host specificity. The results indicated that these two strains represent a novel species, for which we propose the name Helicobacter cappadocius with faydin-H75T (=NCTC014972 = LMG 33382 = DSM117062) as the respective type strain. The current novel species is the first Helicobacter species to exhibit a psychrotrophic feature.

Climate Futures for Lizards and Snakes in Western North America May Result in New Species Management Issues.

We assessed changes in fundamental climate-niche space for lizard and snake species in western North America under modeled climate scenarios to inform natural resource managers of possible shifts in species distributions. We generated eight distribution models for each of 130 snake and lizard species in western North America under six time-by-climate scenarios. We combined the highest-performing models per species into a single ensemble model for each scenario. Maps were generated from the ensemble models to depict climate-niche space for each species and scenario. Patterns of species richness based on climate suitability and niche shifts were calculated from the projections at the scale of the entire study area and individual states and provinces, from Canada to Mexico. Squamate species' climate-niche space for the recent-time climate scenario and published known ranges were highly correlated (r = 0.81). Overall, reptile climate-niche space was projected to move northward in the future. Sixty-eight percent of species were projected to expand their current climate-niche space rather than to shift, contract, or remain stable. Only 8.5% of species were projected to lose climate-niche space in the future, and these species primarily occurred in Mexico and the southwestern U.S. We found few species were projected to lose all suitable climate-niche space at the state or province level, although species were often predicted to occupy novel areas, such as at higher elevations. Most squamate species were projected to increase their climate-niche space in future climate scenarios. As climate niches move northward, species are predicted to cross administrative borders, resulting in novel conservation issues for local landowners and natural resource agencies. However, information on species dispersal abilities, landscape connectivity, biophysical tolerances, and habitat suitability is needed to contextualize predictions relative to realized future niche expansions.

Redescription of Raillietiella mottae (Raillietiellidae: Pentastomida) a generalist parasite of insectivorous lizards: phenotypic plasticity revealed by molecular data.

Pentastomida are lung parasites of a variety of hosts, mainly reptiles. Raillietiella is the genus with the largest number of species, whose taxonomic identification is still largely based on morphological data alone. In this classification, differences divide the genus into morphotypic groups. The Raillietiella parasites of insectivorous lizards, for example, are divided into "Group I" with species with hooks with sharp tips and "Group II" with posterior hooks with blunt tips. In the present work, we used molecular analysis to infer the morphological variation in hooks and size of specimens of Raillietiella mottae, parasites of several species of insectivorous lizards. Our results demonstrate that morphological differences comprise a phenotypic plasticity of a single species, whose variation is associated with host species, with females being larger and with hooks with blunt tips in nocturnal geckos and smaller ones with sharp tips in diurnal insectivorous lizards of different species, sizes, and habitats.

Morphological Study of Left-Right Head Asymmetry in Doubledaya bucculenta (Coleoptera: Erotylidae: Languriinae).

Left-right asymmetry in paired organs is well documented across various species, including the claws of fiddler crabs and snail-eating snakes' dentition. However, the mechanisms underlying these asymmetries remain largely elusive. This study investigates Doubledaya bucculenta (Coleoptera: Erotylidae), a lizard beetle species known for pronounced left-sided asymmetry in adult female mandible and gena. Given that insect mouthparts comprise multiple functionally significant appendages, we aimed to clarify the degree of asymmetry extending beyond the mandibles and genae. Phenotypic morphology was assessed through trait measurement and asymmetry index calculations. Our detailed morphometric analyses revealed left-longer asymmetry not only in mandibles and genae but also in maxillae and labium. Notably, the degree of asymmetry in other mouthparts was generally less pronounced compared to that in outer mandibles, suggesting a potential influence of left mandible development on other mouthparts. Additionally, male mandibles exhibited region-specific asymmetry, potentially indicative of constrained evolutionary adaptations. This study enhances a comprehensive understanding of adult phenotype morphology and offers insights into the developmental basis of asymmetrical mouthparts.