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Within captive management programs for species of conservation concern, understanding the genetic mating system is of fundamental importance, given its role in generating and maintaining genetic diversity and promoting opportunities for sperm competition. If a goal of a conservation program is reintroduction, knowledge of the mating system may also inform prediction models aimed at understanding how genetic diversity may be spatially organized, thus informing decisions regarding where and which individuals should be released in order to maximize genetic diversity in the wild population. Within captive populations, such information may also influence how animals are maintained in order to promote natural behaviors. Here we investigate the genetic mating system of the Guatemalan beaded lizard, Heloderma charlesbogerti, a member of a genus lacking such information. A group of adult male and female H. charlesbogerti were co-habited for five years during the species perceived breeding season. Through genomic parentage analysis, 50% of clutches comprising multiple offspring were found to result from polyandry, with up to three males siring offspring within single clutches. Furthermore, males were found to be polygamous both within and across seasons, and females would exhibit promiscuity across seasons. As such, within this captive environment, where opportunities existed for mating with multiple sexual partners, the genetic mating system was found to be highly promiscuous, with multiple paternity common within clutches. These findings are novel for the family Helodermatidae, and the results have broader implications about how reproductive opportunities should be managed within captive conservation programs.

Species vary extensively in geographic range size and climatic niche breadth. If range limits are primarily determined by climatic factors, species with broad climatic tolerances and those that track geographically widespread climates should have large ranges. However, large ranges might increase the probability of population fragmentation and adaptive divergence, potentially decoupling climatic niche breadth and range size. Conversely, ecological generalism in large-ranged species might lead to higher gene flow across climatic transitions, increasing species' cohesion and thus decreasing genetic isolation by distance (IBD). Focusing on Australia's iconic

Interspecific aggression has important fitness consequences across the animal kingdom and can be especially important during species invasions, where asymmetric interactions between native and invasive species can lead to native species declines. We investigated the immediate behavioural consequences of interspecific interactions for a native species, the green anole lizard, Anolis carolinensis, after an invasion by a closely related invasive species, the Cuban brown anole, Anolis sagrei. We housed captive populations of green anoles (6 males, 6 females) in large outdoor enclosures and recorded their display behaviours (displays/min), activity levels (movements/min) and habitat use (2D and 3D home range size, perch height) for 10 days. We then introduced brown anoles and recorded the green anoles' behaviours for another 10 days, seeking differences between pre- and post-invasion behaviours. We recorded behavioural interactions between individuals (i.e. headbob and dewlap displays, chases, mating attempts, fights and copulations) throughout the study. To serve as a density control, we duplicated the experiment in a second enclosure using green anoles as ‘invaders’. We performed the experiment eight times with two densities of invaders: high (4 males, 4 females) and low (2 males, 2 females). We found that green anoles have smaller two-dimensional and three-dimensional home ranges and higher average perch heights after invasions but that these changes resulted from increased population densities rather than aggression from brown anole invaders. Furthermore, although green and brown anoles did display to each other, both species preferentially interacted with conspecifics and escalated aggressive behaviours between the two species (e.g. lock-jawed fights) rarely occurred. Taken together, these findings indicate that high brown anole population densities, rather than direct interference competition, could be driving green anole displacement across the brown anole's invasive range.

Competition between animals for limited resources often involves signaling to establish ownership or dominance. In some species, the defended resource relates to suitable thermal conditions and refuge from predators. This is particularly true of burrow-dwelling lizards such as the Qinghai toad-headed agama (Phrynocephalus vlangalii), which are found on the Tibetan plateau of western China. Male and female lizards occupy separate burrows, which are vital for anti-predator behaviour during warmer months when lizards are active and, crucially, provide shelter from harsh winter conditions. These lizards are readily observed signaling by means of tail displays on the sand dunes they inhabit. Given the selective pressure to hold such a resource, both males and females should exhibit territorial behaviour and we considered this study system to examine in detail how social context influences motion based territorial signaling. We confirmed that territorial signaling was used by both sexes and by adopting a novel strategy that permitted 3D reconstruction of tail displays, we identified significant variation due to social context. However, signal structure was not related to lizard morphology. Clearly, the burrow is a highly valued resource and we suggest that additional variation in signaling behaviour might be mediated by resource quality.

Climate-modulated parasitism is driven by a range of factors, yet the spatial and temporal variability of this relationship has received scant attention in wild vertebrate hosts. Moreover, most prior studies overlooked the intraspecific differences across host morphotypes, which impedes a full understanding of the climate-parasitism relationship. In the common lizard (Zootoca vivipara), females exhibit three colour morphs: yellow (Y-females), orange (O-females), and mixed (mixture of yellow and orange, M-females). Zootoca vivipara is also infested with an ectoparasite (Ophionyssus mites). We therefore used this model system to examine the intraspecific response of hosts to parasitism under climate change. We found infestation probability to differ across colour morphs at both spatial (10 sites) and temporal (20 years) scales: M-females had lower parasite infestations than Y- and O-females at lower temperatures, but became more susceptible to parasites as temperature increased. The advantage of M-females at low temperatures was counterbalanced by their higher mortality rates thereafter, which suggests a morph-dependent trade-off between resistance to parasites and host survival. Furthermore, significant interactions between colour morphs and temperature indicate that the relationship between parasite infestations and climate warming was contingent on host morphotypes. Parasite infestations increased with temperature for most morphs, but displayed morph-specific rates. Finally, infested M-females had higher reductions in survival rates than infested Y- or O-females, which implies a potential loss of intraspecific diversity within populations as parasitism and temperatures rise. Overall, we found parasitism increases with warming temperatures, but this relationship is modulated by host morphotypes and an interaction with temperature. We suggest that epidemiological models incorporate intraspecific diversity within species for better understanding the dynamics of wildlife diseases under climate warming.

To understand the spread of parasite and the persistence of infection in an ecological environment, it is essential to investigate their transmission possibilities. Vertical transmission of pathogens from mother to offspring is a fundamental opportunity, notwithstanding a relatively under-researched topic, especially in wildlife animals. We studied whether there is vertical transmission of a haemogregarinid blood parasite of Iberian green lizard (Lacerta schreiberi). To study infection of mothers, embryos and freshly hatched juveniles, their blood smears and molecular analyses of their tail tissue were used. Examining blood smears, seventy-one percent of females were found to be infected, but molecular analyses of all mothers showed positive results for the blood parasite. Based on molecular data the parasite was identified as a Karyolysus species. In contrast, no parasite was found in the blood smears of the freshly hatched juveniles, and we could not detect Karyolysus in the embryos or tail tissue of offspring using molecular methods either. Based on our results, vertical transmission of Karyolysus blood parasites is unlikely in the Iberian green lizard., Graphical abstract Image 1, Highlights • Molecular analyses showed a Karyolysus species infects Lacerta schreiberi. • All females-mothers but none of their embryos and offspring were infected. • Vertical transmission of Karyolysus genus is unlikely in the Iberian green lizard.

Running speed and camouflage are associated with the foraging and anti‐predator abilities of animals. The toad‐headed lizard, Phrynocephalus versicolor, has evolved a darker dorsal color in melanistic habitats and maintained a lighter color in adjacent, non‐melanistic habitats. We test the hypothesis that lizards have weaker running speed on well‐matching backgrounds than on less matching backgrounds. We used lizard models to compare the predation pressure, while the running speed of dark and light lizards were compared in field tunnels using a video recording method. Our results indicated that both the dark lizards in melanistic Heishankou (HSK) and the light lizards in non‐melanistic Guazhou (GZ) face lower predation pressure than potential color‐background unmatched lizards. The light lizards have a potentially higher running speed than darker lizards in melanistic habitats, which implies that substrate color matching populations with benefits of camouflage might have lower anti‐predation pressure, and the costs of investment in melanin production may reduce running capacity., The lizards with substrate matching dorsal color have lower predation pressure than substrate unmatched lizards. The dark lizards with benefits of camouflage lowed the running speed in melanistic habitat.

An ecological issue can best be studied by gathering original data that are specifically targeted for that issue. But ascertaining-a priori-whether a novel issue will be worth exploring can be problematic without background data. However, an issue's potential merit can sometimes be evaluated by repurposing legacy or other data that had been gathered for unrelated purposes but that are nonetheless relevant. Our present project was initially motivated by an ecological trade-off-proposed eight decades ago-involving the depth at which desert reptiles overwintered. To address those and related issues, we repurposed our five-decades-old natural history data for 18 species of Kgalagadi lizards and then explored the seasonal ecology of these lizards, emphasizing winter. Our data were not gathered for a study of seasonal ecology but nonetheless inform diverse seasonal patterns for a major community of lizards. However, repurposed data (whether recent or legacy) present challenges and ambiguities, and we suggest targeted, next-step studies of seasonal ecology that can circumvent limitations and ambiguities.

Holcosus gaigeae es una lagartija de tamaño pequeño y cuerpo moderadamente robusto que tiene una distribución restringida a la porción Mexicana de la Península de Yucatán. La información existente acerca de su ecología e historia natural es limitada. En este escrito se presentan observaciones de depredación, dieta y reproducción de H. gaigeae en diferentes porciones de los estados de Yucatán y Campeche, en México, las cuales aportan nueva información acerca de los aspectos ecológicos de esta especie.

Males of several bird species across diverse orders and families court females and mate with them offering so-called nuptial gifts, mostly food. This subject has been scarcely studied in the Neotropical avifauna, and no research has focused on a given family or order. We present herein an outline on nuptial gifts among Brazilian cuckoo species, based on databases from citizen science, gathered by birdwatchers. In the databases, we obtained 29 photographic records of seven cuckoo species mating with a gift. In the field, we recorded an unsuccessful attempt at mating with the offer of a small lizard. Five species offered invertebrates (insects), and three offered vertebrates (frogs and lizards). Vertebrates were recorded for two Crotophaginae cuckoos (two times each), but only a single recent record for a Cuculinae species was obtained with this nuptial gift type. Most records of nuptial gifts are of two common and widespread species, whereas those for the remaining five species are scarce. We presume that the species that offered vertebrates as a nuptial gift optimized the female’s breeding condition. We suggest that additional citizen science effort by birders, as well as natural history-oriented studies by professionals, will increase our knowledge about nuptial gifts among Neotropical Cuculiformes. This reasoning is suitable for other bird orders and/or families.

Physiology is crucial for the survival of invasive species in new environments. Yet, new climatic conditions and the limited genetic variation found within many invasive populations may influence physiological responses to new environmental conditions. Here, we studied the case of the delicate skinks (Lampropholis delicata) invading Lord Howe Island (LHI), Australia. On LHI, the climate is different from the mainland source of the skinks, and independent introduction events generated invasive populations with distinct genetic backgrounds. To understand how climate and genetic background may shape physiological responses along biological invasions, we compared the physiological traits of a source and two invasive (single-haplotype and multi-haplotype) populations of the delicate skink. For each population, we quantified physiological traits related to metabolism, sprint speed, and thermal physiology. We found that, for most physiological traits analysed, population history did not influence the ecophysiology of delicate skinks. However, invasive populations showed higher maximum speed than the source population, which indicates that locomotor performance might be a trait under selection during biological invasions. As well, the invasive population with a single haplotype was less cold-tolerant than the multi-haplotype and source populations. Our results suggest that limited genetic variability and climate may influence physiological responses of invasive organisms in novel environments. Incorporating the interplay between genetic and physiological responses into models predicting species invasions can result in more accurate understanding of the potential habitats those species can occupy.

Climate change represents a real threat to biodiversity conservation worldwide. Although the effects on several species of conservation priority are known, comprehensive information about the impact of climate change on reptile populations is lacking. In the present study, we analyze outcomes on the potential distribution of the black beaded lizard (Heloderma alvarezi Bogert & Martin del Campo, 1956) under global warming scenarios. Its potential distribution, at present and in projections for the years 2050 and 2070, under both optimistic and pessimistic climate change forecasts, were computed using current data records and seven bioclimatic variables. General results predict a shift in the future potential distribution of H. alvarezi due to temperature increase. The optimistic scenario (4.5 W/m2) for 2070 suggests an enlargement in the species’ distribution as a response to the availability of new areas of suitable habitat. On the contrary, the worst-case scenario (7 W/m2) shows a distribution decrease by 65%. Moreover, the range distribution of H. alvarezi is directly related to the human footprint, which consequently could magnify negative outcomes for this species. Our research elucidates the importance of conservation strategies to prevent the extinction of the black beaded lizard, especially considering that this species is highly threatened by aversive hunting.

Aim . Comparison of two methods (genetic and morphological) for assessing the polymorphism of populations of the eastern sand lizard ( Lacerta agilis exigua ) in two ecologically different localities. Material and Methods . For this, we used the method of polylocus genotyping of genomic DNA regions flanked by inverted repeats of microsatellites and fragments of long terminal repeats of endogenous retroviruses, as well as the assessment of a number of phenotypic characteristics. The material was lizards (a total of 55 adults) caught in two localities: in the Novonikolaevsky District of the Volgograd Region and in the vicinity of the Strizhament mountain, Stavropol Territory. Results . Of the two methods for assessing the state of the population genetic structure of the eager lizard, the most informative for identifying interpopulation and sex differences was a comparative analysis of the spectra obtained using microsatellite sequences and sites of endogenous retroviruses. This method made it possible to identify the most polymorphic DNA markers, which make it possible to obtain the most informative spectra in terms of the number of loci and polymorphism necessary for describing the genetic structures and their dynamics in the eastern darting lizard with high resolution. Conclusion . The studies carried out allowed us to identify the most informative indicators for describing population structures and their dynamics in the eastern darting lizard. For the first time, data were obtained indicating that the greatest contribution to interpopulation differentiation in different localities of capture is made by the variability of males compared to females.

Questing behavior and host associations of immature blacklegged ticks, Ixodes scapularis Say, from the southeastern United States are known to differ from those in the north. To elucidate these relationships we describe host associations of larval and nymphal I. scapularis from 8 lizard species sampled from 5 sites in the southeastern U.S. Larvae and nymphs attached in greater numbers to larger lizards than to smaller lizards, with differential levels of attachment to different lizard species. Blacklegged ticks are generally attached to skinks of the genus Plestiodon in greater numbers per unit lizard weight than to anoles (Anolis) or fence lizards (Sceloporus). The broad-headed skink, Plestiodon laticeps (Schneider), was a particularly important host for immature I. scapularis in our study and in several previous studies of tick–host associations in the southeast. Blacklegged ticks show selective attachment to Plestiodon lizard hosts in the southeast, but whether this results from behavioral host preferences or from ecological factors such as timing or microhabitat distributions of tick questing and host activity remains to be determined.

During epidermal differentiation in the scales of lizards and snakes, from the basal layer beta- and later alpha-keratinocytes are generated to form beta-and alpha-corneous layers. In the lizard Anolis carolinensis, minor proteins derived from the EDC (Epidermal Differentiation Complex) are added to the main constituent proteins, IFKs (Intermediate Filament Keratins) and CBPs (Corneous Beta Proteins, formerly indicated as beta keratins). One of these proteins that previous studies showed to be exclusively expressed in the skin, EDWM (EDC protein containing high GSRC amino acids) is rich in cysteine and arginine, amino acids that form numerous –S–S– and electro-static chemical bonds in the corneous material. Light and electron microscopy immunolbeling for EDWM show a diffuse localization in differentiating beta-cells and in some alpha-cells, in particular those of the clear-layer, involved in epidermal shedding. The study suggests that EDWM may function as a matrix protein that binds to IFKs and CBPs, contributing to the formation of the specific corneous material present in beta- and alpha-corneous layers. In particular, its higher immunolocalization in the maturing clear layer indicates that this protein is important for its differentiation and epidermal shedding in A. carolinensis and likely also in other lepidosaurian reptiles.

As the only viviparous reptile in China that has both temperature-dependent sex determination (TSD) and genetic-dependent sex determination (GSD) mechanisms, Eremias multiocellata is considered as an ideal species for studying the sex determination mechanism in viviparous lizards. However, studies on embryonic stage of viviparous lizards and morphological characteristics of each stage are limited. In the present study, the embryonic development process of E. multiocellata is divided into 15 stages (stages 28–42) according to the morphology of embryos. Embryos sizes are measured and continuous dynamic variation of some key features, including limbs, genitals, eyes, pigments, and brain scales are color imaged by a stereoscopic microscope. Furthermore, based on these morphological characteristics, we compare the similarities and differences in the embryonic development of E. multiocellata with other squamate species. Our results not only identified the staging table of E. multiocellata with continuous changes of external morphological characteristics but also developed a staging scheme for an important model species that provides a necessary foundation for study of sex determination in a viviparous lizard.

Global climate change is already contributing to the extirpation of numerous species worldwide, and sensitive species will continue to face challenges associated with rising temperatures throughout this century and beyond. It is especially important to evaluate the thermal ecology of endangered ectotherm species now so that mitigation measures can be taken as early as possible. A recent study of the thermal ecology of the federally endangered Blunt‐nosed Leopard Lizard (Gambelia sila) suggested that they face major activity restrictions due to thermal constraints in their desert habitat, but that large shade‐providing shrubs act as thermal buffers to allow them to maintain surface activity without overheating. We replicated this study and also included a population of G. sila with no access to large shrubs to facilitate comparison of the thermal ecology of G. sila populations in shrubless and shrubbed sites. We found that G. sila without access to shrubs spent more time sheltering inside rodent burrows than lizards with access to shrubs, especially during the hot summer months. Lizards from a shrubbed site had higher midday body temperatures and therefore poorer thermoregulatory accuracy than G. sila from a shrubless site, suggesting that greater surface activity may represent a thermoregulatory trade‐off for G. sila. Lizards at both sites are currently constrained from using open, sunny microhabitats for much of the day during their short active seasons, and our projections suggest that climate change will exacerbate these restrictions and force G. sila to use rodent burrows for shelter even more than they do now, especially at sites without access to shrubs. The continued management of shrubs and of burrowing rodents at G. sila sites is therefore essential to the survival of this endangered species., The Blunt‐Nosed Leopard Lizard is a federally endangered ectotherm adapted to California's San Joaquin Desert ecosystem. We compared a population of lizards who had access to shrubs to a population of lizards who had no access to shrubs in the Carrizo Plain National Monument, and found that lizards who do not have access to shrubs thermoregulated more accurately (unexpected), with a trade‐off of being forced underground into cooler burrows for more of the day compared with lizards who had access to shrubs.

Animals inhabiting arid environments use a variety of behavioural and physiological strategies to balance their water and salt budgets. We studied the effects of dehydration and salt loading on osmoregulatory capacities in a large herbivorous desert lizard, the Moroccan Spiny-tailed lizard Uromastyx nigriventris, the family Agamidae. These lizards select plants with a high K+ to Na+ ratio of 15 to 20, and like other herbivorous lizards, effectively eliminate the extra electrolyte load, mainly via a pair of active nasal salt glands, which exude the extra ions from blood. Here we present results of a series of laboratory experiments, which tested a five-week food and water deprivation and the excretory response of nasal salt glands, during a short period of five days, following salt loading by two separated injections of KCl or NaCl at a 5-day interval (4th and 9th days). During food-water deprivation, hypohydrated lizards lost 32% of their initial body mass with a substantial decrease of their Body Condition Index and the tail volume as an index of energy (fat and then potential metabolic water) storage. Plasma osmolality significantly increased by 20%. There were also significantly increased plasma sodium, chloride, and total protein concentrations. On the other hand, there was no significant decrease in the plasma glucose level. Most of the salt loaded lizards secreted far more K+ than Na+ via the nasal glands, even after NaCl loading. The K+/Na+ ratio decreased only after two to three repetitive NaCl injections but insufficient Na+ was eliminated. Two successive KCl injections were successfully eliminated, but daily natural average K+ administration induced progressive hyperkaliemia. These experimental data agreed with previous observations showing variations of plasma Na+ and K+ concentrations in free-living lizards. The nasal gland constitutes the main route of Cl− excretion but the Cl−/(Na+ + K+) ratio may vary according to observations in other herbivorous species.

Abstract The Lindholm rock lizard, Darevskia lindholmi, is the only member of the genus Darevskia whose range is restricted solely to Europe, representing a local endemism found only in the Crimean Mountains. In our study, we investigated the cytochrome b gene (mtDNA) of 101 D. lindholmi sequences from 65 Crimean localities, representing its entire range. We found that D. lindholmi is highly genetically structured, and its range is divided into populations belonging to three mitochondrial lineages. The Lindholm rock lizard populations inhabiting the middle part of the Crimean Mountains (further referred to as the Central lineage) are sharply differentiated from the other two lineages (the Common and the Southwestern lineages), which are present in most of the species range. The genetic distance between the Central lineage and the other two taken together is 4.6%, according to our results, suggesting that the divergence occurred during the Early Pleistocene. The narrowly distributed Southwestern lineage and the widespread Common lineage, on the other hand, are differentiated by 1%. Field observations on the representatives of the main evolutionary groups show that their ecology is also different: the Central lineage is a mesophilic and cold-resistant form, while the other two closely related lineages are more xerophilic and thermophilic. Results of the potential ranges modeling and ecological niche analysis confirm that the genetic lineages occupy different niches of the Crimea. Furthermore, the area of inhabitation of the Central lineage splits the western and eastern parts of the Common lineage range, while the Southwestern lineage is restricted along the coast of the southwestern coast of the peninsula. The long-term co-existence of deeply divergent sister mitochondrial lineages in a relatively small (circa 7,000 km2) isolated mountain system serves as a mesocosm for understanding the speciation process. Our data suggest that the Central lineage warrants further taxonomic investigation.

Though biological invasions constitute one of the biggest threats for global biodiversity, our understanding of the mechanisms that enable invasive species to outperform native species is still limited, especially, in terms of behavior. Most available studies have examined behavioral traits which favor invasive species on the later stages of invasion, however, our knowledge on earlier stages, namely, when alien species face novel environments and must exploit new resources, remains obscure. Here, we focus on one crucial behavioral trait, finding food. The Italian wall lizard (Podarcis siculus) has been widely introduced and established viable populations in S. Europe and N. America. We examined whether P. siculus has enhanced exploratory behavior and abilities to find food compared to two native congeneric species with which it may come in contact in the near future, an insular endemic (P. milensis) and a widely distributed lizard (P. erhardii). We performed a Y-maze experiment, in which we varied arm markings in a standard way to prevent learning. Podarcis siculus was more efficient than its congenerics in finding and consuming food. This exploitative superiority was persistent, more frequent and repetitive. Interesting behavioral differences were also detected within the native species. Some P. milensis individuals showed no interest in exploring the maze, while few P. erhardii individuals remained rather indifferent to food even after detecting it. Our results suggest that the invasive P. siculus displays behavioral traits that could provide better opportunities for survival in the new environment and thus facilitate establishment even in the presence of congenerics. This provides further support to the idea that behavior plays a crucial role in animal invasions.

A body plan (bauplan) is a suite of morphological characters shared by phylogenetically related animals at some point during their development. Despite its value, the bauplan concept is still rarely employed to characterize functional groups in community ecology. Here, we examine habitat use and spatio-temporal activity correlates of an entire seven-species community of lizards with different bauplans. The study was carried out in three locations in central Italy, encompassing a complex landscape with a patchy mosaic of a wide variety of habitats and microclimates. We tested four hypotheses regarding niche breadth, habitat use, and activity patterns. The first hypothesis, niche complementarity, in which species with similar body shapes should non-randomly partition available habitats, was not supported. By contrast, the hypotheses that larger bodied species should have a wider niche breadth, that slower species should inhabit habitat types of higher cover, and species inhabiting open sunny habitats should exhibit more seasonally variable activity patterns, were all supported by the data. Sympatric lizard communities in our study area were clearly organized by autecological constraints and eco-physiological attributes.

Australian lizards are a diverse group distributed across the continent and inhabiting a wide range of environments. Together, they exhibit a remarkable diversity of reproductive morphologies, physiologies, and behaviours that is broadly representative of vertebrates in general. Many reproductive traits exhibited by Australian lizards have evolved independently in multiple lizard lineages, including sociality, complex signalling and mating systems, viviparity, and temperature-dependent sex determination. Australian lizards are thus outstanding model organisms for testing hypotheses about how reproductive traits function and evolve, and they provide an important basis of comparison with other animals that exhibit similar traits. We review how research on Australian lizard reproduction has contributed to answering broader evolutionary and ecological questions that apply to animals in general. We focus on reproductive traits, processes, and strategies that are important areas of current research, including behaviours and signalling involved in courtship; mechanisms involved in mating, egg production, and sperm competition; nesting and gestation; sex determination; and finally, birth in viviparous species. We use our review to identify important questions that emerge from an understanding of this body of research when considered holistically. Finally, we identify additional research questions within each topic that Australian lizards are well suited for reproductive biologists to address.

Mediterranean islands have a high diversity of squamates, although they are unevenly distributed. This variability in the composition of the reptile assemblages across islands may have been influenced by differences in the colonization abilities of these species. To evaluate the dispersal capacities of squamate species, we modeled their sea routes using cost surface models. We estimated the effects of some life‐history traits and the phylogenetic signal in the characteristics of the modeled dispersal paths. We hypothesized that a significant phylogenetic signal should be present if the dispersal ability is enhanced by traits shared among evolutionarily related species. The results showed that no phylogenetic signal was present in the characteristics of the dispersal paths (i.e., in the distance traveled/bypassed sea depth). Thus, no superior island‐colonizer lineages were detected in Mediterranean Squamata. However, our analyses also revealed that small‐sized lizards were superior to other groups of squamates at dispersing over long distances on the sea., The dispersal of reptiles throughout the Mediterranean islands lacks a phylogenetic structure. Only small lizards appear to be better dispersers, but this trait evolved independently in several unrelated lineages.

Background and Aim: The high prevalence of sparganosis has been reported globally, especially in Asian countries where the majority of individuals consume raw meat from wild-caught reptiles. In Indonesia, similar cases regarding the high prevalence of sparganosis were recorded from wild reptiles such as snakes that utilized for culinary purposes, whereas, there are no data regarding other species such as water monitor lizard (Varanus salvator), which also provided as daily culinary with a high number of trades. Therefore, this study aims to investigate the prevalence of sparganosis in water monitor lizard (V. salvator), which is frequently utilized as culinary products in East Java Province, Indonesia. Materials and Methods: A total of 313 living wild-caught and captive-bred Asian water monitor lizards were collected from the reptile markets and breeders. All samples were euthanized and observed for the presence of plerocercoid. Identification of the plerocercoid as larval infective stage was made using carmine staining method. Results: The total prevalence of sparganosis was recorded at 69.64%. A total of 393 plerocercoids were collected in which divided 280 (71.24%) infecting muscles and 113 (28.75%) located in subcutaneous tissues. Conclusion: To the best of our knowledge, this study not only recorded as the first evidence but also confirms the role of monitor lizards as sparganosis transmitters in Asia and reveals additional routes of sparganosis transmission in Indonesian reptiles. Local conservation laws should be strengthened to effectively control or ban wildlife trade in traditional markets. Moreover, public awareness regarding sparganosis as a neglected zoonotic disease should be applied to prevent disease transmission in Indonesia.

Trade-offs between reproduction and survival are central to life-history theory and are expected to shape patterns of phenotypic selection, but the ecological factors structuring these trade-offs and resultant patterns of selection are generally unknown. We manipulated reproductive investment and predation regime in island populations of brown anole lizards (Anolis sagrei) to test (1) whether previously documented increases in the survival of experimentally non-reproductive females (OVX = ovariectomy) reflect the greater susceptibility of reproductive females (SHAM = control) to predation and (2) whether phenotypic selection differs as a function of reproductive investment and predation regime. OVX females exceeded SHAM controls in growth, mass gain and body condition, indicating pronounced energetic costs of reproduction. Although mortality was greatest in the presence of bird and snake predators, differences in survival between OVX and SHAM were unrelated to predation regime, as were patterns of natural selection on body size. Instead, we found that body condition at the conclusion of the experiment differed significantly across populations, suggesting that local environments varied in their ability to support mass gain and positive energy balance. As mean body condition improved across populations, the magnitude of the survival cost of reproduction increased, linear selection on body size shifted from positive to negative, and quadratic selection shifted from stabilizing to weakly disruptive. Our results suggest that reproductive trade-offs and patterns of phenotypic selection in female brown anoles are more sensitive to inferred variation in environmental quality than to experimentally induced variation in predation.

Within populations, individuals often differ consistently in their average level of behavior (i.e., animal personality), as well as their response to environmental change (i.e., behavioral plasticity). Thus, changes in environmental conditions might be expected to mediate the structure of animal personality traits. However, it is currently not well understood how personality traits change in response to environmental conditions, and whether this effect is consistent across multiple populations within the same species. Accordingly, we investigated variation in personality traits across two ecological contexts in the invasive delicate skink (Lampropholis delicata). Specifically, lizards from three different populations were repeatedly measured for individual activity in group behavioral assays under differing levels of food availability. We found that environmental context had a clear effect on the structure of lizard personality, where activity rates were not repeatable in the absence of food, but were repeatable in the presence of food resources. The difference in repeatability of activity rates across contexts appeared to be largely driven by an increase in among-individual variance when tested in the presence of food resources. However, this was only true for one of the populations tested, with food context having no effect on the expression of personality traits in the other two populations. Our results highlight the important role of environmental context in mediating the structure of animal personality traits and suggest that this effect may vary among populations.

A list of amphibian and reptile species that occur in open and forested areas of the Atlantic Forest in the municipality of Cruz das Almas, in the Recôncavo Baiano, eastern Brazil is presented. Field sampling occurred between January 2015 to March 2019, totalling 117 samples distributed in three areas: Parque Florestal Mata de Cazuzinha, Mata da Cascalheira, and Riacho do Machado. A total of 1,848 individuals of 69 species (31 anurans, 14 lizards, 19 snakes, two amphisbaenians, and three testudines) was recorded. Additionally, one individual of Ophiodes striatus was found in Mata da Cascalheira after the end of sampling, totalling 15 lizard species and 70 herpetofaunal species. The prevalence of open-area species and the presence of Phyllopezus lutzae, Diploglossus lessonae, and Dryadosaura nordestina in interior forest patches are discussed. Additionally, a new record of the invasive terrapin Trachemys dorbigni in the State of Bahia is reported.

We document the first verifiable records of Heloderma alvarezi (Bogert & del Campo, 1956) in southeastern Guerrero, Mexico. We recorded seven individuals of H. alvarezi near the village of Cihuapoloya, municipality of Cuautepec. These are the westernmost records of the species, extending its distribution by approximately 149 km from the nearest previously known occurrences in Oaxaca. With these records, the number of reptile species in Guerrero increases to 182.

The body temperature of lizards is strongly influenced by the thermal quality of microhabitats, exploiting the favourable environmental temperatures, and avoiding exposure to extreme thermal conditions. For these reasons, reptile populations are considered to be especially vulnerable to changes in environmental temperatures produced by climate change. Here, we study the thermal physiology of the critically endangered Añelo Sand Dunes Lizard (Liolaemus cuyumhue Avila, Morando, Perez and Sites, 2009). We hypothesise that (i) there is a thermal coadaptation between optimal temperature for locomotor performance of L. cuyumhue and its thermal preference; (ii) L. cuyumhue lives in an environment with low thermal quality; and (iii) a rise in environmental temperatures due to global warming will impose a decrement in locomotor speed represented by lower warming tolerance and narrower thermal safety margins, increasing their already high vulnerability. We recorded field body temperatures (T b), preferred body temperatures (T pref), the operative temperature (T e), and the thermal sensitivity of locomotion at different body temperatures. Our results indicate that this lizard is not currently under environmental stress or exceeding its thermal limits, but that it is thermoregulating below T pref to avoid overheating, and that an increase in environmental temperature higher than 3.5 °C will strongly affect the use of microhabitats with direct sun exposure.

The early evolution of diapsid reptiles is marked by a deep contrast between our knowledge of the origin and early evolution of archosauromorphs (crocodiles, avian and non-avian dinosaurs) to that of lepidosauromorphs (squamates (lizards, snakes) and sphenodontians (tuataras)). Whereas the former include hundreds of fossil species across various lineages during the Triassic period1, the latter are represented by an extremely patchy early fossil record comprising only a handful of fragmentary fossils, most of which have uncertain phylogenetic affinities and are confined to Europe1–3. Here we report the discovery of a three-dimensionally preserved reptile skull, assigned as Taytalura alcoberi gen. et sp. nov., from the Late Triassic epoch of Argentina that is robustly inferred phylogenetically as the earliest evolving lepidosauromorph, using various data types and optimality criteria. Micro-computed tomography scans of this skull reveal details about the origin of the lepidosaurian skull from early diapsids, suggesting that several traits traditionally associated with sphenodontians in fact originated much earlier in lepidosauromorph evolution. Taytalura suggests that the strongly evolutionarily conserved skull architecture of sphenodontians represents the plesiomorphic condition for all lepidosaurs, that stem and crown lepidosaurs were contemporaries for at least ten million years during the Triassic, and that early lepidosauromorphs had a much broader geographical distribution than has previously been thought. Taytalura alcoberi, represented by a three-dimensionally preserved skull from the Late Triassic epoch of Argentina, is phylogenetically inferred as the earliest known lepidosauromorph, and reveals that sphenodontian skull architecture is plesiomorphic for lepidosaurs.

We describe a new species of gymnophthalmid lizard, Oreosaurus bisbali sp. nov., from the Turimiquire Massif in northeastern Venezuela. It is one of three reptile species known to be endemic to the region and the fifth species of Oreosaurus from Venezuela. It can be distinguished from all congeners by a combination of rectangular dorsal scales at midbody, having two scales separating femoral pores medially, and lacking a nasoloreal suture. The new species is likely to be restricted in distribution to the highlands of the Turimiquire Massif, which have been significantly degraded by agriculture.

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Life history theory predicts that there should be an inverse relationship between offspring size and number, because individuals cannot simultaneously maximize both when resources are limited. Although extensively studied in avian species, the occurrence and determinants of reproductive tradeoffs in oviparous reptiles are far less understood, particularly in parthenogenetic species. We studied this trade-off in the Colorado Checkered Whiptail, Aspidoscelis neotesselatus, a female-only parthenogenetic lizard. Using data previously collected in 2018 and 2019, we tested for clutch and egg size trade-offs and determined whether this relationship could be influenced by female size and aspects of physiological condition. Physiological condition included energy-mobilizing hormone (i.e. corticosterone ‘CORT’), oxidative stress (i.e. reactive oxygen metabolites ‘ROMs’), and innate immune function (bacterial killing ability ‘BKA’). We found the effect of clutch size on follicle size was significant, but not linear. Specifically, follicle size was on average larger in females with clutches of two follicles when compared to clutches of one follicle, but smaller in females with clutches of three when compared to clutches of two. In addition, females that were larger produced larger follicles regardless of clutch size. Neither CORT nor BKA affected the relationship between follicle size and clutch size. However, ROMs did explain variability in this relationship: oxidative stress was more elevated in females that produced larger clutches and larger follicles. We conclude that clutch size and body size are key life history traits that shape follicle size, and that investments into larger clutches and follicle size come at the cost of oxidative damage.

Locomotor performance and skeletal muscle contraction are critical for animals and are susceptible to changes in the external thermal environment, especially for ectotherms. Phrynocephalus erythrurus, which is endemic to the Qinghai–Tibetan plateau, is known for living at the highest elevation among all reptiles in the world (4500–5300 m). In this study, which compares P. erythrurus with the lowland Phrynocephalus przewalskii, we evaluated the locomotor performance at different body temperatures, the effects of temperature and oxygen partial pressure (PO2) on the contractile properties of iliofibularis (IF) muscle in vitro, ATPase activity of IF muscle at different temperatures, and the fiber types of IF muscle. Lowland P. przewalskii runs significantly faster than highland P. erythrurus at all test body temperatures. Almost all contractile properties of the IF muscle of P. przewalskii were better than that of P. erythrurus under all test temperatures and PO2. However, P. erythrurus could achieve both optimal isometric (e.g., dPo/dt) and optimal isotonic (e.g., Vmax) contraction at a lower temperature compared with P. przewalskii. Multi-factor analysis further revealed that temperature has a significant effect on the contractile properties of IF muscle for both species. Although the proportion of fibers types and ATPase activities of IF muscle have no significant interspecies difference, the changing pattern of ATPase activities with temperature is consistent with certain contractile properties and locomotor performance. The interspecies differences in locomotor ability and contractile properties of skeletal muscle in high- and low-altitude lizards may be the results of long-term adaptation to the local environment.

This study compared the resource use of juvenile zoo-living Chinese crocodile lizards, Shinisaurus crocodilurus crocodilurus across three observation windows, spanning nine months, accounting for time of day and lizard age, and under consistent environmental conditions. Lizards showed a significant difference in proportionate resource use, quantified using a modified spread of participation indices between the second and final sampling period, such that with increasing age, resources were more equally utilised. The time of day did not have a significant effect on resource use. Lizards in this study significantly increased their use of water bodies and branches outside the bask zone and decreased their use of the land areas within the bask zones over time. Resource use data suggests the importance of providing enclosures which cater to ontogenetic shifts in captive individuals or within mixed age groupings.

Leaving the water to bask (usually in the sun) is a common behavior for many freshwater turtles, with some species also engaging in “nocturnal basking.” Ectoparasite removal is an obvious hypothesis to explain nocturnal basking and has also been proposed as a key driver of diurnal basking. However, the efficacy of basking, day or night, to remove leeches has not been experimentally tested. Therefore, we examined the number of leeches that were removed from Krefft's river turtles (Emydura macquarii krefftii) after experimentally making turtles bask at a range of times of day, durations, and temperatures. Turtles had high initial leech loads, with a mean of 32.1 leeches per turtle. Diurnal basking under a heat lamp for 3 hr at ~28°C significantly reduced numbers of leeches relative to controls. In diurnal trials, 90.9% of turtles lost leeches (mean loss of 7.1 leeches per turtle), whereas basking for 30 min under the same conditions was not effective (no turtles lost leeches, and all turtles were still visibly wet). Similarly, “nocturnal basking” at ~23°C for 3 hr was not effective at removing leeches. Only 18% of turtles lost leeches (one turtle lost one leech and another lost four leeches). Diurnal basking outdoors under direct sunlight for 20 min (mean temp = 34.5°C) resulted in a small reduction in leeches, with 50% of turtles losing leeches and an average loss of 0.7 leeches per turtle. These results indicate basking can remove leeches if temperatures are high or basking durations are long. However, it was only effective at unusually long basking durations in this system. Our data showed even the 20‐min period was longer than 70.1% of natural diurnal basking events, many of which took place at cooler temperatures. Therefore, leech removal does not appear to be the purpose of the majority of basking events., Aerial basking has long been hypothesized to reduce ectoparasites in turtles. We experimentally tested if basking reduced leech loads in an Australian freshwater turtle. While basking can reduce leech loads, the basking duration and heat intensity greatly influence the results. Thus, we have determined that mean basking times in nature were not sufficient to effectively reduce leech loads, making leech removal unlikely to be the primary mechanism driving basking behavior.

Rensch's rule relates to a pattern whereby sexual size dimorphism (SSD) is more female-biased in small-sized species and more male-biased in large-sized ones. We collected literature and museum data on the body size of males and females belonging to 4,032 lizard species, as well as data on their reproductive modes and clutch sizes. We used phylogenetic comparative analyses, and general linear mixed models, to test Rensch's rule and examined how reproductive mode and clutch size affect sexual size dimorphism. Sexual size dimorphism was independent of clutch size in lizard species with variable clutch sizes and in oviparous lizards. Large litters were associated with female-biased sexual dimorphism in viviparous and in scincomorph lizards. Inference regarding Rensch's rule depended on the analytical method used to identify it. The widely used, but less conservative, reduced major axis regression usually support Rensch's rule while ordinary least squares regressions mostly show isometric relationships. The rule tended to apply more to oviparous than viviparous lizards. We infer that Rensch's rule is, at best, a weak pattern in lizards. This is especially true in viviparous lineages, where females reproduce infrequently, therefore evolve large sizes to maximise fecundity, resulting in female-biased dimorphism. This article is protected by copyright. All rights reserved.

Wolbachia, a maternally transmitted Gram-negative endosymbiont of onchocercid nematodes and arthropods, has a role in the biology of their host; thus it has been exploited for the filariasis treatment in humans. To assess the presence and prevalence of this endosymbiont in reptiles and their ectoparasites, blood and tail tissue as well as ticks and mites collected from them were molecularly screened for Wolbachia DNA using two sets of primers targeting partial 16S rRNA and Wolbachia surface protein (wsp) genes. Positive samples were screened for the partial 12S rRNA and cytochrome c oxidase subunit 1 (cox1) genes for filarioids. Of the different species of lizards (Podarcis siculus, Podarcis muralis and Lacerta bilineata) and snakes (Elaphe quatuorlineata and Boa constrictor constrictor) screened from three collection sites, only P. siculus scored positive for Wolbachia 16S rRNA. Among ectoparasites collected from reptiles (Ixodes ricinus ticks and Neotrombicula autumnalis, Ophionyssus sauracum and Ophionyssus natricis mites), I. ricinus (n = 4; 2.8%; 95% CI, 0.9–7) from P. siculus, N. autumnalis (n = 2 each; 2.8%; 95% CI, 0.9–6.5) from P. siculus and P. muralis and O. natricis (n = 1; 14.3%; 95% CI, 0.7–55.4) from Boa constrictor constrictor scored positive for Wolbachia DNA. None of the positive Wolbachia samples scored positive for filarioids. This represents the first report of Wolbachia in reptilian hosts and their ectoparasites, which follows a single identification in the intestinal cells of a filarioid associated with a gecko. This data could contribute to better understand the reptile filarioid-Wolbachia association and to unveil the evolutionary pattern of Wolbachia in its filarial host.

The remarkable ability of geckos to adhere to smooth surfaces is often thought of in terms of external structures, including the branching setae that make contact with the surface producing van der Waals forces. Some geckos also exhibit unique movements of the distal segments of the limbs during locomotion and static clinging, including active digital hyperextension and considerable pedal rotation. During static clinging, geckos can exhibit considerable adduction/abduction of the pes while the crus and thigh remain firmly adpressed to the substratum. This decoupling of pedal adduction/abduction from ankle flexion/extension and pedal long-axis rotation is a significant departure from pedal displacements of a typical lizard lacking adhesive ability. The structure of the ankle is likely key to this decoupling, although no detailed comparison of this complex joint between pad-bearing geckos and other lizards is available. Here we compare the configuration of the mesotarsal joint of nongekkotan lizards (Iguana and Pristidactylus) with that of the Tokay gecko (Gekko gecko) using prepared skeletons, scanning electron microscopy, and micro-computed tomographic (µCT) scans. We focus on the structure of the astragalocalcaneum and the fourth distal tarsal. The mesotarsal joint exhibits a suite of modifications that are likely associated with the secondarily symmetrical pes of pad-bearing geckos. For example, the lateral process of the astragalocalcaneum is much more extensive in G. gecko compared with other lizards. The mesotarsal joint exhibits several other differences permitting dissociation of long-axis rotation of the pes from flexion-extension movement, including a reduced ventral peg on the fourth distal tarsal, an articulatory pattern dominated by a well-defined, expansive distomesial notch of the astragalocalcaneum, and an associated broad proximodorsal articulatory facet of the fourth distal tarsal. Pad-bearing geckos are capable of effectively deploying their intricate adhesive system across a broad array of body angles because of this highly modified ankle. Future research should determine whether the differences encountered in G. gecko (and their extent) apply to the Gekkota as a whole and should examine how the elements of the ankle move dynamically during locomotion across a range of taxa.

Populations that evolved in predictable seasonal environments might not have mechanisms to deal with unpredictable climate change. Assessing whether these populations can cope with recent increases in climate extremes and variability can better inform conservation efforts. We investigated the effects of climate deviations and fire on the population dynamics of the lizard Tropidurus torquatus in the Cerrado of Brazil. We decomposed six climate variables into seasonal and non-seasonal components and assessed which factors, along with long- and short-term effects of fire, better accounted for variation in the survival and recruitment of a T. torquatus population monitored for 12 years. Survival was not associated with climate seasonality, and instead minor fluctuations were related to temperature extremes. Recruitment benefited from long-term fire effects and had a strong seasonal component accounting for most of the variation in the population. Climate deviations caused severe changes in the number of recruits each year, with an overall negative effect on population growth. Population growth was more sensitive to recruitment than to survival, resulting in a sharp population decline over the study period. Tropidurus torquatus, and perhaps other species that evolved in similar conditions, can mitigate the demographic effects of fire but lack mechanisms to deal with climate deviation occurring over relatively short periods.

The research on animal colouration has always been of great interest for biologists but since the last decades it has grown exponentially thanks to multidisciplinary approaches. Animals have found several ways to deal with the camouflage/communication trade-off in colouration, leading to the evolution of alternative patterns of variation of colourations at different levels including signal partitioning and spatial resolution of colouration. In this paper we analyse the variability of dorsal and ventral colouration in males and females of Maltese wall lizards in three populations on Linosa. We collected high-resolution digital images of dorsal, ventral and throat colouration from 61 lizards (32 males and 29 females). We showed that the colouration differs among sexes and body regions within the same individual. Colourations are also variable among individuals within population, as well as among different populations across the Island. Finally, we detected a lizard’s colouration shifts with increasing body size. Those result supports the hypothesis that colouration in this species evolved under the competing pressures of natural and sexual selection to promote signals that are visible to conspecifics while being less perceptible to avian predators. Graphic abstract

Invasive species can carry parasites to introduced locations, which may be key to understand the success or failure of species establishment and the invasive potential of introduced species. We compared the prevalence and infection levels of haemogregarine blood parasites between two sympatric congeneric species in Lisbon, Portugal: the invasive Italian wall lizard (Podarcis siculus) and the native green Iberian wall lizard (Podarcis virescens). The two species had significant differences in their infection levels: while P. virescens had high prevalence of infection (69.0%), only one individual of P. siculus was infected (3.7%), and while P. virescens exhibited an average intensity of 1.36%, the infected P. siculus individual had an infection rate of only 0.04%. Genetic analyses of 18S rRNA identified two different haemogregarine haplotypes in P. virescens. Due to the low levels of infection, we were not able to amplify parasite DNA from the infected P. siculus individual, although it was morphologically similar to those found in P. virescens. Since other studies also reported low levels of parasites in P. siculus, we hypothesize that this general lack of parasites could be one of the factors contributing to its competitive advantage over native lizard species and introduction success.

Despite the commonly held belief that reptiles are immune to extreme temperatures, global warming is predicted to result in the loss of 40% of all reptile species by 2080. In order to understand th...