Lizard Species Research Articles

Правило Фостера или островной эффект у популяций ушастой круглоголовки (Phrynocephalus mystaceus) и быстрой ящурки (Eremias velox) (Reptilia, Lacertilia) на песчаном массиве Сарыкум

The sandy massif Sarykum, whose age is about 100 thousand years, is an island habitat for psammophilic species of terrestrial vertebrates. The paper presents new morphometric data on the populations of two species of psammophilous lizards living in this area. These are the nominative subspecies of the Secret Toadheaded Agama (Phrynocephalus mystaceus mystaceus Pallas, 1776) and the Caucasian Central Asian Racerunner (Eremias velox caucasica Lantz, 1928). Body length of sexually mature males of the Secret Toadheaded Agama averages 76.5±3.7 mm (n = 30), and adult females – 68.9±4.2 mm (n = 29). Comparison of the obtained materials with similar parameters of the Kazakhstan population of the subspecies shows that mature individuals of the Sarykum population are significantly smaller: for males td = 1.33 ≥ tst with a confidence level α = 0.80, and for females td = 2.07 ≥ tst with α = 0.95. It is known from the literature that all the pre-Caucasian populations of this species are isolated. Perhaps the small size of mature individuals in them also serve as an example of the manifestation of Foster's rule. The data of the presented study indicate a similar feature of the Sarykum population of the Caucasian Central Asian Racerunner. The body length of mature males at Sarykum is 63.6±2.9 mm (n = 9), and that of females is 58.4±3.0 mm (n = 17). The calculation of the reliability of differences by the Student coefficient shows that the length of the trunk of males (td = 2) and females (td = 0.61) of the Sarykum population does not statistically differ from the averaged materials for the region. At the same time, mature individuals of the Sarykum population are significantly smaller than the nominative subspecies from Kazakhstan: for males td = 1.40 ≥ tst with a confidence probability α = 0.80, and for females td = 2.20 ≥ tst with α = 0.95. It is obvious that Foster's rule does not manifest itself in the subspecies population living on the Sarykum sandy massif, and the conspicuous small size of mature individuals is determined by comparison with the size of the nominative subspecies. An interesting fact is that immature foot-and-mouth of both species do not differ in size from individuals of the same age of other populations. Probably, at this stage of ontogenesis, the overall physiologically optimal size for the species is preserved.

Redescription of two Bornean gekkonid lizard species of the Cyrtodactylus consobrinus (Peters, 1871) complex with comments on online supplementary material

In a recent paper in Zoologica Scripta, the formal diagnoses and descriptions of two new Bornean gekkonid gecko species of the Cyrtodactylus consobrinus (Peters, 1871) complex were included in online supplementary material. Although the new nomina were associated with ZooBank registration identifiers, the supplementary document in which these LSIDs appeared was not published in a format with fixed content and layout. As such, the new nomina cannot be considered to have been promulgated in the electronic version of the paper, as it was not compliant with the International Code of Zoological Nomenclature as amended in 2012. A subsequently published printed version of the paper did make these nomina nomenclaturally available but, following author guidelines, relegated the descriptions and diagnoses, including data critical to justifying recognition of these new cryptic taxa, to online supplementary material. Because of the impermanence of this supplementary document, we here provide the diagnoses, descriptions and type specimen data for these two Cyrtodactylus. We recommend that taxonomists refrain from publishing works containing taxon descriptions and other nomenclatural acts in journals that require critical data to be placed in online supplementary documents.

BACK FROM THE BEYOND: DEFENSIVE BEHAVIOR OF THE BOGOTA ANADIA Anadia bogotensis (SQUAMATA: GYMNOPHTHALMIDAE).

Lizards exhibit various behaviors, including death-feigning behavior. Here, we present the first record of death-feigning behavior in Anadia bogotensis, an endemic lizard species of Colombia.

The lifestyle of the leopard gecko and the importance of ultraviolet radiation, vitamin D and calcium

The gecko leopard (Eublepharis macularius) was first described in 1854 by British herpetologist Edward Blyth. It is one of the most popular pet lizard species, due to its docile temperament, ease of maintenance and reproduction in captivity, its high longevity and small size, and its beauty and diversity of colours and patterns. Ultraviolet (UV) radiation is an important behavioural regulator. Vitamin D also regulates many fundamental physiological functions in vertebrates, mainly calcium homeostasis. Because of the great diversity of reptile species and the wide range of environmental adaptations, it is important to know the necessities and adaptations of each species regarding UV, vitamin D and calcium requirements. This study provides an overview of the leopard gecko’s lifestyle, and the importance of ultraviolet radiation, vitamin D and calcium for this species.

3D printed models are an accurate, cost-effective, and reproducible tool for quantifying terrestrial thermal environments

Predicting ecological responses to rapid environmental change has become one of the greatest challenges of modern biology. One of the major hurdles in forecasting these responses is accurately quantifying the thermal environments that organisms experience. The distribution of temperatures available within an organism's habitat is typically measured using data loggers called operative temperature models (OTMs) that are designed to mimic certain properties of heat exchange in the focal organism. The gold standard for OTM construction in studies of terrestrial ectotherms has been the use of copper electroforming which creates anatomically accurate models that equilibrate quickly to ambient thermal conditions. However, electroformed models require the use of caustic chemicals, are often brittle, and their production is expensive and time intensive. This has resulted in many researchers resorting to the use of simplified OTMs that can yield substantial measurement errors. 3D printing offers the prospect of robust, easily replicated, morphologically accurate, and cost-effective OTMs that capture the benefits but alleviate the problems associated with electroforming. Here, we validate the use of OTMs that were 3D printed using several materials across eight lizard species of different body sizes and living in habitats ranging from deserts to tropical forests. We show that 3D printed OTMs have low thermal inertia and predict the live animal's equilibration temperature with high accuracy across a wide range of body sizes and microhabitats. Finally, we developed a free online repository and database of 3D scans (https://www.3dotm.org/) to increase the accessibility of this tool to researchers around the world and facilitate ease of production of 3D printed models. 3D printing of OTMs is generalizable to taxa beyond lizards. If widely adopted, this approach promises greater accuracy and reproducibility in studies of terrestrial thermal ecology and should lead to improved forecasts of the biological impacts of climate change.

Myrmecophagy in lizards: evolutionary and ecological implications

Abstract 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.

Habitat turnover in Iberian and Italian lizards: Is it climatically, spatially, or phylogenetically determined?

AbstractThe Mediterranean peninsulas host rich assemblages of lizards, but little is known about the factors that limit their habitat use on large spatial scales. In this study, we investigated the variation in habitat use of 29 species of lacertid lizards on the Iberian and Italian peninsulas and the transitional region of southeastern France. We investigated whether the types of habitat used were phylogenetically determined or, in contrast, were more influenced by spatial or climatic effects. We characterized the vegetal composition of 483 habitats used by lacertids and estimated the contribution of each component to habitat variability using distance‐based redundancy analysis. We showed that overall turnover patterns were determined similarly in both peninsulas, despite differences in the composition of the lacertid assemblages. The aridity‐related component dominated over the phylogenetic one, which has a weak influence in both regions. The species showed different turnover patterns, being low in those present in cold alpine habitats and shrub‐steppe specialists. In some Iberian endemics, habitat turnover occurs within relatively homogeneous climatic bands. However, in the Italian species, habitat turnover has a comparatively stronger climatic component, suggesting lower climatic specialization. This study shows that species distributions across habitats provide information to assess community properties and can be applied to explore differences among faunal assemblages over large geographic areas. Our results provide evidence that beta diversity can play a key role in structuring patterns of habitat turnover.

Non-additive effects of multiple predators alter the biological control of the coffee leaf miner (Leucoptera coffeella)

Although most prey are attacked by multiple predators, much of the ecological theory on prey suppression focuses on the effects of a single predator. The presence of multiple predators can lead to complex interactions such as trait-mediated interactions (TMIIs) and intraguild predation which can influence the suppression of pest populations. Here we explore the effect of two predators, a native anole lizard species Anolis cristatellus (Squamata: Dactyloidae) and a non-native ant species Wasmannia auropunctata (Hymenoptera: Formicidae), on the coffee leaf miner, Leucoptera coffeella (Lepidoptera: Lyonetiidae) (CLM). In a laboratory experiment we examined the effects of these two predators in isolation and when co-occurring. Our results show that when each predator is alone, they are able to consume the CLM in a comparable way. However, when they are together, their effect is not greater than when alone. This indicates that there is a negative effect when both predators co-occur. The results from this experiment have practical implications since both predators are present in coffee agroecosystems in Puerto Rico, where the CLM is considered the main insect pest. Furthermore, these results demonstrate the potential dynamics among several predators in agroecosystems and the potential implications for herbivore regulation.

Phylogenetic Analyses of Lizards from the Chilean Humboldt Archipelago Reveal a New Species for the Chañaral Island (Squamata: Liolaemidae).

The Humboldt Archipelago, situated on Chile's north-central coast, is renowned for its exceptional biodiversity. However, lizards of the Liolaemus genus are a particularly understudied group in this archipelago. Liolaemus genus is divided into two clades: chiliensis and nigromaculatus. Within the nigromaculatus clade the zapallarensis group is restricted to the semi-arid and arid coastal habitats of the Atacama Desert in north-central Chile. While it has been reported that lizards from the zapallarensis group inhabit various islands within the Humboldt Archipelago, there has been limited knowledge regarding their specific species identification. To identify the lizard species inhabiting these islands, we conducted phylogenetic analyses using a mitochondrial gene and examined morphological characteristics. Our findings reveal that lizards from the Damas, Choros, and Gaviota islands belong to Liolaemus silvai. In contrast, the lizards on Chañaral Island form a distinct and previously unrecognised group, clearly distinguishable from Liolaemus silvai. In conclusion, our study not only confirms the presence of L. silvai on the Damas, Choros, and Gaviota islands but also describes a new lizard species on Chañaral Island named Liolaemus carezzae sp. nov. These findings contribute valuable insights into the biodiversity of these islands and introduce a newly discovered endemic taxon to the region, enriching our understanding of Chile's unique island ecosystems.

A mixture of artificial and biological sounds improves the effective range of an acoustic repellent for an invasive lizard species

AbstractFurther range expansion of invasive animal species can be prevented by controlling their behavior. Acoustic repellent is a promising approach to deter problematic animals from ecologically sensitive areas. To develop an acoustic repellent system for a green anole that was introduced to the Ogasawara islands in Japan, this study evaluated the deterrent effect of (1) a pattern sound of machine noise and (2) a mixture of artificial and biologically relevant sounds. We created a sound level gradient inside a small experimental cage in a laboratory setting and measured whether green anoles avoided the vicinity of a speaker. In approximately 80% of cases, both the pattern machine sound and the mixture sounds prevented green anoles from stepping into the vicinity of a speaker (<24 cm). The mixture sounds maintained the deterrent effect at a middle distance from a speaker (<72 cm), whereas the pattern machine sound did not work as a strong acoustic repellent at this distance. These results imply that the mixing of biotic and abiotic sounds can improve the effective range of acoustic repellent for green anoles. However, several shortcomings of the acoustic repellent system were also highlighted. Since a green anole is an insectivore predator, our findings will contribute to protecting endangered native insect fauna from the predation of non‐native lizard species.

UPDATED DISTRIBUTION MAP OF Amphisbaena mitchelli PROCTER, 1923 (SQUAMATA: AMPHISBAENIDAE) WITH A NEW RECORD IN MARANHÃO, BRAZIL

Amphisbaena mitchelli is a small-sized worm lizard species described from Ilha de Marajó, state of Pará, Brazil. After its description, few publications brought new distribution records for A. mitchelli, all in eastern Amazonia. In this paper we report a new record of the species in municipality of Imperatriz, state of Maranhão, Brazil. The new record is the first in the Cerrado ecoregion and is 300km northeast in straight line to the closest record in Floresta Nacional de Carajás, municipality of Parauapebas, state of Pará, Brazil, and fills a gap of 530 km.

Foraging mode constrains the evolution of cephalic horns in lizards and snakes.

A phylogenetically diverse minority of snake and lizard species exhibit rostral and ocular appendages that substantially modify the shape of their heads. These cephalic horns have evolved multiple times in diverse squamate lineages, enabling comparative tests of hypotheses on the benefits and costs of these distinctive traits. Here, we demonstrate correlated evolution between the occurrence of horns and foraging mode. We argue that although horns may be beneficial for various functions (e.g. camouflage, defence) in animals that move infrequently, they make active foragers more conspicuous to prey and predators, and hence are maladaptive. We therefore expected horns to be more common in species that ambush prey (entailing low movement rates) rather than in actively searching (frequently moving) species. Consistent with that hypothesis, our phylogenetic comparative analysis of published data on 1939 species reveals that cephalic horns occur almost exclusively in sit-and-wait predators. This finding underlines how foraging mode constrains the morphology of squamates and provides a compelling starting point for similar studies in other animal groups.

Dehydration alters behavioral thermoregulation and the geography of climatic vulnerability in two Amazonian lizards.

High temperatures and low water availability often strike organisms concomitantly. Observing how organisms behaviorally thermohydroregulate may help us to better understand their climatic vulnerability. This is especially important for tropical forest lizards, species that are purportedly under greater climatic risk. Here, we observed the influence of hydration level on the Voluntary Thermal Maximum (VTmax) in two small Amazonian lizard species: Loxopholis ferreirai (semiaquatic and scansorial) and Loxopholis percarinatum (leaf litter parthenogenetic dweller), accounting for several potential confounding factors (handling, body mass, starting temperature and heating rate). Next, we used two modeling approaches (simple mapping of thermal margins and NicheMapR) to compare the effects of dehydration, decrease in precipitation, ability to burrow, and tree cover availability, on geographic models of climatic vulnerability. We found that VTmax decreased with dehydration, starting temperature, and heating rates in both species. The two modeling approaches showed that dehydration may alter the expected intensity, extent, and duration of perceived thermal risk across the Amazon basin for these forest lizards. Based on our results and previous studies, we identify new evidence needed to better understand thermohydroregulation and to model the geography of climatic risk using the VTmax.

Towards digital descriptions of all extant reptile species

Vertebrate databases have been slow to digitize species descriptions. One of them, the Reptile Database (http://www.reptile-database.org), has accumulated ~8,000 species descriptions for ~3,000 species of snakes, ~5,000 species of lizards, and ~150 species of turtles and crocodiles. Here we discuss how this data contributes to character analysis, species identification, but also to integration with other data sources such as citizen science observations (which depend on correct identifications). Importantly, the data described here may serve as training data for machine learning projects and we present examples of species comparisons using ChatGPT. While these AI-driven comparisons are still erroneous, we expect substantial improvements in the near future. We request the herpetological community to help complete our public collection of species descriptions and suggest that other species databases follow suit and provide similar data for their taxa.

Metabolic regulation reduces the oxidative damage of arid lizards in response to moderate heat events.

Climate warming poses a significant threat to species worldwide, particularly those inhabiting arid and semi-arid regions where extreme temperatures are increasingly prevalent. However, empirical studies investigating how moderate heat events affect the physiological processes of arid and semi-arid animals are largely scarce. To address this knowledge gap, we used an arid and semi-arid lizard species (Phrynocephalus przewalskii) as a study system. We manipulated thermal environments to simulate moderate heat events (43.5 ± 0.3°C during the heating period) for lizards and examined physiological and biochemical traits related to survival, metabolism, locomotion, oxidative stress, and telomere length. We found that the body condition and survival of the lizards were not significantly affected by moderate heat events, despite an increase in body temperature and a decrease in locomotion at high test temperatures were detected. Mechanistically, we found that the lizards exhibited down-regulated metabolic rates and enhanced activities of antioxidative enzymes, resulting in reduced oxidative damage and stable telomere length under moderate heat events. Based on these findings, which indicated a beneficial regulation of fitness by physiological and biochemical processes, we inferred that moderate heat events did not have a detrimental effect on the toad-headed agama, P. przewalskii. Overall, our research contributes to understanding the impacts of moderate heat events on arid and semi-arid species and highlights the adaptive responses and resilience exhibited by the toad-headed agama in the face of climate warming.

What is behind the success of terrestrial bromeliads as microhabitat for the sylvatic triatomine Mepraia spinolai?

Puya alpestris, P. berteroniana and P. chilensis (Bromeliaceae) are terrestrial plants present in north-central Chile, considered important part of the shrub flora due to their abundance and close interaction with animals. A previous study showed that bromeliad cover positively correlates with the abundance of the sylvatic triatomine vector Mepraia spinolai, only when infected by the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. Here, we assessed the biological interactions and abiotic conditions provided by these Puya species to M. spinolai. During the austral summers of 2015 and 2016, we sampled 17 sites with presence of M. spinolai colonies. In each site, we estimated the presence of bromeliad and its cover proportion, and placed a camera trap for three months near a M. spinolai colony to record the vertebrates potentially interacting with this triatomine. Three of the camera traps were placed right in front of M. spinolai-colonized bromeliads. At the same time, triatomines present under these bromeliads were collected to assess their blood meal by Next Generation Sequencing. Between July 2017 and January 2018, we examined the abiotic conditions (temperature and humidity) under bromeliad, under rocks and at ground level. We detected 40 vertebrate species associated to Puya spp. (18 birds, 16 mammals, and 6 reptiles). Puya spp. are a resource for keystone species in T. cruzi sylvatic transmission, including small mammals (Octodon degus, Phyllotis darwini) and lizard species (Liolaemus spp.), detecting a positive association between bromeliad presence and availability of reptiles and non-domestic mammals. Native rodents and humans were the most represented vertebrates in the diet of M. spinolai collected under bromeliads. Temperatures were more stable under bromeliad, showing lower amplitude (up to 14.3 °C) compared to under rocks (23.7 °C) or at ground level (49.6 °C). Bromeliads present in the semiarid-Mediterranean ecosystem provide feeding opportunities for triatomines, and act as buffer of abiotic conditions reducing daily thermal amplitude. The presence of bromeliads near human settlements should be carefully monitored, especially because their leaves are consumed by people and browsed by livestock present in endemic areas of Chagas disease.

Trophic niche and adaptation in highland lizards: sex has greater influences than species matching.

The plateau environments are typically arid, cool, and high altitude, posing formidable challenges to wildlife survival due to resource scarcity and harsh conditions. Unraveling ecological adaptability in severe conditions requires a deeper understanding of the niche characteristics of plateau species. Trophic niche, which is a comprehensive indicator describing the energy acquisition strategy of animals, remains relatively understudied in plateau species. Here, by combining stable isotopes and morphological data, we quantified the trophic niches of two allopatric lizard species (Phrynocephalus vlangalii and P. erythrurus) that live in the hinterland of the Qinghai-Tibetan Plateau,and explored how their trophic niches correlate with morphological and environmental factors. While both trophic niche and morphological traits were similar between species, noteworthy distinctions were observed between male and female Phrynocephalus lizards. The morphological traits associated with predation (i.e. limb length and head size) and reproduction (i.e. abdomen length), annual mean temperature, and sex played influential roles in shifting trophic niches. These results imply that sexual dimorphism may facilitate inter-sex divergence in resource utilization, leading to trophic niche variations in the highland lizards. Furthermore, extreme environmental stress can constrain interspecific divergence in morphological and trophic traits. Our findings illustrate the dynamic variations of trophic niches in highland lizards, contributing to a more comprehensive understanding of the adaptation strategies employed by lizard species in plateau environments.

Identifying the abiotic factors that determine the inland range limits of a mesic-adapted lizard species.

For most species, the factors that determine geographical range limits are unknown. In mesic-adapted species, populations occurring near the edge of the species' distribution provide ideal study systems to investigate what limits distributional ranges. We aimed to identify the abiotic constraints that preclude an east-Australian mesic-adapted lizard (Lampropholis delicata) from occupying arid environments. We performed lizard surveys at sites spanning an elevation/aridity gradient (380-1070 m) and measured the prevalence of habitat features (logs, rocks, leaf litter, bare ground, solar radiation) in addition to hourly temperatures in a variety of microhabitats available to lizards. Species distribution models (SDM) were used to identify the macroclimatic variables limiting the species' distribution. At its inland range limit, L. delicata is associated with mesic high-elevation forests with complex microhabitat structures, which gradually decline in availability toward lower (and more arid) elevations where the species is absent. Moreover, L. delicata is absent from sites with a shallow leaf litter layer, in which daily temperatures exceed the species' thermal preference range, which we determined in a laboratory thermal gradient. In regards to macroclimate, SDM revealed that temperature seasonality is the primary variable predicting the species' distribution, suggesting that L. delicata avoids inland areas owing to their high annual thermal variability. By combining multiple lines of evidence, this research highlights that habitat and microclimate suitability-not solely macroclimate suitability-are important range-limiting factors for mesic ectotherms and should be incorporated in studies addressing range-limiting hypotheses.

Spontaneous quantity discrimination in the Australian sleepy lizard (Tiliqua rugosa)

Abstract Animals employ quantitative abilities to gauge crucial aspects of their environment, such as food or predator density in a given area or the number of eggs in a nest. These quantitative skills hold ecological implications and can impact an animal’s fitness. However, our comprehension of how these abilities intersect with environmental challenges remains limited. We tested for spontaneous quantity discrimination in the sleepy lizard (Tiliqua rugosa), a long-lived species known for forming life-long pair bonds in which pairs come together for the breeding season. We subjected lizards to a Y-maze experiment presenting both discrete (comparisons involving two vs. four, two vs. six, two vs. eight, four vs. six, four vs. eight, and six vs. eight pieces) and equivalent continuous combinations (single pieces differing in size) of pumpkin pieces. Our findings revealed that sleepy lizards exhibited spontaneous quantity discrimination, favoring the larger quantity in three discrete comparisons (eight vs. two, two vs. six, four vs. six) and two continuous comparisons (eight vs. two, eight vs. four). However, low accuracy may be attributable to difficulty in visual acuity exacerbated by difficulty discriminating quantities at small ratios. Furthermore, we found no evidence for a speed-accuracy trade-off in their decision-making process. Our results suggest that sleepy lizards likely employ multiple cues to estimate quantity accurately. Considering these results in the context of previous studies on various lizard species, it becomes apparent that lizards, as a group, offer a valuable model for unraveling the evolution of cognition, given their diverse ecology and sociobiology.

A picture is worth a thousand dollars: a photographic approach to studying colour in anoles

Abstract Colours relay information to conspecifics and predators unique to an environment and are shaped by natural selection favouring colours that enable higher fitness. For decades, ecologists have grappled with various methods of quantifying colour. Spectrophotometers offer precise and accurate data, but their high price limits accessibility. Here we test the validity of an accessible method of quantifying colour. We analysed photographs from four species of Anolis lizards from urban and forest habitats. We compared dewlap colour in order to determine if photographic analysis can detect inter- and intraspecific differences with the same power as a spectrophotometer. We hypothesized that photographs would capture colour data comparable to a spectrophotometer within the visible light range, and that habitat divergence would be associated with intraspecific differences in dewlap. We demonstrate, as hypothesized, that photographic colour data are consistent with spectrophotometer data and capable of differentiating dewlap variation within the visible light spectrum. Differences in colour between urban and forest populations were significant for some but not all species, and the part of the colour spectrum that shifted was not consistent across species. Our results support photographic analysis as an alternative for quantifying colour to study both inter- and intraspecific variation in visible colour.