Search Results (13)

While most lizard species are polygamous, dominant males typically have greater access to females and copulate more frequently than submissive ones. Several studies suggest that applying assisted reproduction techniques to this taxon could be an effective tool to enhance conservation programs. Therefore, the proper selection of males for assisted breeding programs is crucial for their overall success. In this study, we report for the first time data on semen and sperm quality from dominant males of the Mexican lizard Sceloporus torquatus using techniques commonly employed in assessing mammalian fertility. The semen and sperm characteristics were as follows: volume, 14.0 µL; sperm concentration, 125.7 × 10⁶ cells/mL; wave motion, 2.7; total motility, 87.8%; sperm viability, 89.0%; normal morphology, 88.8%; plasma membrane integrity, 87.7%; low plasma membrane fluidity, 94.9%; capacitation status: uncapacitated (F), 90.5%; capacitated (B), 7.2%; sperm with acrosome reaction (AR), 2.3%; and, acrosome integrity, 88.8%. These results suggest that, according to mammalian fertility parameters, dominant males of S. torquatus are fertile. This series of tests provides a valuable tool for conducting a comprehensive analysis of the functional changes that may occur in sperm handling during assisted processes, and that may contribute—along with the proper selection of individuals—to reproductive success. Full article

Scaled integument of six species of the genus Acanthocercus and Laudakia nupta, family Agamidae was studied using light and scanning electron microscopy. Gross observation revealed the presence of two types of modified scales in the males. The enlarged scales covered with an extremely thick β-corneous layer were detected in the dorsal and ventral surfaces of the tail base and on the palmar and plantar limb surfaces of all species. After detachment of the β-layer, the surface of such scales was covered with high papillae (“papillary scales”). The callous scales were found in the precloacal region of Acanthocercus species and in both precloacal and mid-ventral regions of L. nupta. Modified scales were found in some females and subadut specimens, and absent in juveniles. A prominent papillary layer characterized the dermis of both scale types. It was assumed that well-developed dermal papillae in such scales expended the total surface area of stratum germinativum and created a pool of proliferated cells in the interpapillary loops to increase the production of differentiating keratinocytes. These processes were undoubtedly associated with the formation of a thick and resistant corneous layer that distinguished both types of scales. Functional role, a taxonomic value, and analogies with normal and pathological epidermis in birds and mammals are discussed. Full article

While there are millions of reptile images available online, they are not well organized and not easily findable, accessible, interoperable, or reproducible (FAIR). More importantly, they are not standardized and thus hardly comparable. Here we present a reference database of more than 14,000 standardized images of 1045 reptile species (969 lizard and 76 snake species) that are based on preserved specimens in 20 different collections, including 533 type species of genera and type specimens of 72 species. All images were taken with standardized views, including dorsal and ventral body shots as well as dorsal, ventral, and lateral views of the heads and other body parts. Although only 11 out of the 20 collections are cross-referenced in VertNet, some others are indexed in GBIF, and this fraction will certainly grow in the near future. The utility of this and similar image collections will further grow with additional material and further cross-referencing, e.g., to DNA sequence databases or citizen science projects. The images are searchable and freely available on Morphobank (Project 5121) and on Figshare. Full article

Reptiles are known to be asymptomatic carriers of various zoonotic pathogens. A number of Gram-negative opportunistic commensals are causative agents of bacterial infections in immunocompromised or stressed hosts and are disseminated by reptiles, whose epidemiological role should not be neglected. Since most studies have focused on exotic species, in captivity or as pet animals, the role of wild populations as a potential source of pathogens still remains understudied. In the present study, we isolated a variety of Gram-negative bacteria from the cloacal microbiota of free-living lizard and tortoise hosts (Reptilia: Sauria and Testudines) from the Bulgarian herpetofauna. We evaluated their pathogenic potential according to their antibiotic susceptibility patterns, biofilm-forming capacity, and extracellular production of some enzymes considered to play roles as virulence factors. To our knowledge, the phenotypic manifestation of virulence factors/enzymatic activity and biofilm formation in wild reptile microbiota has not yet been widely investigated. All isolates were found to be capable of forming biofilms to some extent and 29.6% of them could be categorized as strong producers. Two strains proved to be excellent producers. The majority of the isolated strains showed extracellular production of at least one exoenzyme. The most pronounced pathogenicity could be attributed to the newly isolated Pseudomonas aeruginosa strain due to its multiresistance, excellent biofilm formation, and expression of exoenzymes. Full article

This study describes a novel species of Gekko (Squamata: Gekkonidae) based on its distinct morphological features and molecular evidence, which was identified in the Dabie Mountains on the border of Anhui and Henan provinces of Central China. Gekko kaiyai sp. nov. could be distinguished from its congeners owing to its morphological characteristics, such as being a medium body sized gecko species (snout–vent length, 56.98–64.99 mm, n = 4, females; 50.03–61.56 mm, n = 11, males); nostrils scale in contact with rostral scale; tubercles on the dorsal and limb, while the upper forelimb is smooth with no tubercles; 22–33 interorbital scales between the anterior corners of the eyes; 157–209 ventral scales between mental and cloacal slit; 90–121 midbody scale rows; 30–43 ventral scale rows; 7–9 sub-digital lamellae on first fingers, 8–13 fourth fingers, 7–9 first toes, and 7–11 fourth toes; free of webbing in the fingers and toes; 9–12 pre-cloacal pores in males, which are absent in females; post-cloacal unilateral tubercles 1 (few 2); and a dorsum that is greyish white to dark brown, with 6–7 brown markings between the nape and sacrum. The phylogenetic tree based on the mitochondrial DNA sequences (16S, CYTB, and COI) indicated that Gekko kaiyai sp. nov. form an independent clade with strong support (100/1) and are a sister group to G. hokouensis. At the inter-species level, the genetic distances were all large, further confirming that an independent species had been identified. The discovery of this species implies that there are now 87 identified species in the genus Gekko, 22 of which can be found within China. Full article

Understanding the spatial ecology of species has important implications for conservation, as it helps identify suitable habitats and minimum requirements for biodiversity monitoring and management. The spiny-tailed lizard Oplurus cyclurus is a widespread endemic iguanid occurring in dry areas of southern and western Madagascar. While the species is known to be mostly arboreal, populations of the Isalo sandstone massif suggest local adaptation to a less forested savannah and a more exposed habitat. We radio-tracked 19 spiny-tailed lizards to investigate the species’ rock-dwelling behaviour and spatial ecology at Isalo National Park. Tracked individuals showed high site and burrow fidelity, and a basking behaviour mostly tied to the accessibility of their burrow, the time of day, and their life stage. Activity peaked during the sunniest hours, while juveniles were more active than adults with unfavourable weather conditions. Despite high burrow fidelity, lizards used shelters non-exclusively, regularly changing (approx. once a week) with neighbouring burrows (average distance between burrows = 13.6 m). However, there was no obvious relation between lizards’ body and/or tail size and the width and depth of selected burrows. Dynamic Brownian Bridge Movement Models estimated frequented areas over 247.8 m² (95% isopleth), where territorial overlap is common. Our results challenge the notion that burrow-site fidelity is the sole driving factor behind space utilization in the studied population. We argue that the apparently unusual saxicolous habits imposed by habitat features (the absence of trees) may lead to local behavioural adjustments influencing antipredatory and foraging strategies, as well as intraspecific interactions. Full article

The high level of endemism in Fergana Valley has been well documented in numerous studies for various groups of animals and plants. In a relatively small area, there are 45 endemic plant species, five endemic insect species, and five endemic reptile species. In surveying this area for data on distribution, abundance, acoustics, and genetic samples for species of reptiles, we discovered two new species of gecko from the genus Alsophylax. Phylogenetic analyses of mitochondrial DNA sequences indicate the relatives of these new species are the even-fingered gecko, Alsophylax pipiens, and the southern even-fingered gecko, Alsophylax laevis, located hundreds of kilometers to the northwest and southwest of the Fergana Valley. The threats to these new endemic species are significant given the amount of continued agricultural development that involves new territories previously considered “unsuitable” for any species of significance that is leading to the further reduction in, fragmentation of, and degradation of the remaining natural ecosystems in the Fergana Valley. The conservation of these rare and locally endemic species depends directly on the readiness of the state to create areas with IUCN I and II protection. The many studies documenting levels of endemism, along with the data published in this study, are the basis for the justification for state-protected areas in the Fergana Valley. Full article

Osteoderms are bony structures that develop within the dermal layer of the skin in vertebrates and are very often found in different lizard families. Lizard osteoderms are diverse in topography, morphology, and microstructure. Of particular interest are the compound osteoderms of skinks, which are a complex of several bone elements known as osteodermites. We present new data on the development and regeneration of compound osteoderms based on the results of a histological and Computed Microtomography (micro-CT) study of a scincid lizard: Eurylepis taeniolata. The specimens studied are stored in the herpetological collections of the Saint-Petersburg State University and Zoological Institute of the Russian Academy of Sciences located in St. Petersburg, Russia. The topography of osteoderms in the integuments of the original tail area and its regenerated part was studied. A comparative histological description of the original and regenerated osteoderms of Eurylepis taeniolata is presented for the first time. The first description of the development of compound osteoderm microstructure in the process of caudal regeneration is also presented. Full article

Many indigenous foods are nutrient-rich but are often underutilized even among populations at high risk of malnutrition. The aims of this study were to conduct value chain analysis of one cultivated crop (finger millet among the Munda tribe) and one wild green leafy vegetable (Koinaar leaves among the Sauria Paharia tribe) of two Indigenous communities in Jharkhand state, India and to identify entry points for interventions aimed at supporting production and consumption. Semi-structured interviews were conducted with stakeholders among each tribal group and transcripts were open coded and organized based on key themes across the steps of the value chain for each food independently. Improved storage techniques and infrastructure, machinery for processing and improved cooking fuel would help reduce barriers across the finger millet supply chain related to postharvest losses, processing labor and safety concerns related to cooking. For Koinaar leaves, improving drying techniques to increase consumption across seasons and providing training and support to increase opportunities for selling leaves in local markets, where participants mentioned potential language barriers, could strengthen the supply chain. Improving extension services and focusing beyond production has potential to improve the production and consumption of both nutrient-rich crops among Indigenous communities in India. Full article

The Kokshaal racerunner, Eremias kokshaaliensis Eremchenko et Panfilov, 1999, together with other central Asian racerunner species, is included in the Eremias multiocellata complex. In the present work, for the first time, the results of the analysis of historical mitochondrial DNA (barcode) are presented and the taxonomic status and preliminary phylogenetic relationships within the complex are specified. We present, for the first time, the results of the molecular analysis using historical DNA recovered from specimens of several species of this complex (paratypes of the Kokshaal racerunner and historical collections of the Kashgar racerunner E. buechneri from Kashgaria) using DNA barcoding. Full article

Lizards represent unique model organisms in the study of sex determination and sex chromosome evolution. Among tetrapods, they are characterized by an unparalleled diversity of sex determination systems, including temperature-dependent sex determination (TSD) and genetic sex determination (GSD) under either male or female heterogamety. Sex chromosome systems are also extremely variable in lizards. They include simple (XY and ZW) and multiple (X₁X₂Y and Z₁Z₂W) sex chromosome systems and encompass all the different hypothesized stages of diversification of heterogametic chromosomes, from homomorphic to heteromorphic and completely heterochromatic sex chromosomes. The co-occurrence of TSD, GSD and different sex chromosome systems also characterizes different lizard taxa, which represent ideal models to study the emergence and the evolutionary drivers of sex reversal and sex chromosome turnover. In this review, we present a synthesis of general genome and karyotype features of non-snakes squamates and discuss the main theories and evidences on the evolution and diversification of their different sex determination and sex chromosome systems. We here provide a systematic assessment of the available data on lizard sex chromosome systems and an overview of the main cytogenetic and molecular methods used for their identification, using a qualitative and quantitative approach. Full article

We present a review of the data on the intervertebral autotomy and regeneration of agamid lizards based on an analysis of information obtained over a 35-year period after the publication of thorough reviews (Arnold, 1984, 1988 and Bellairs, Bryant, 1985). It is supplemented by our own studies of 869 specimens of agamid lizards (Sauria, Agamidae) stored in the herpetological collections of the Zoological Institute of the Russian Academy of Sciences (St. Petersburg, Russia) and the Zoological Museum of the Moscow State University (Moscow, Russia), represented by 31 species of 16 genera. The manifestations of the ability for autotomy and regeneration in phylogenetic lineages within the family—Leiolepidinae, Amphibolurinae, Agaminae, Draconinae—are considered. A comparative morphological analysis of the structure of the caudal vertebrae was carried out using the Computer Microtomography Methods (micro-CT) in the following ecomorphological types of agama: (1) with developed abilities to caudal autotomy and regeneration, (2) with the ability to caudal autotomy but without regeneration and (3) without the ability to autotomy. The phenomenon of intervertebral autotomy (urotomy) in snakes is considered too. Possible ways of evolution of the ability to caudal autotomy as a defense strategy against predators are discussed in the phylogenetic context. Full article

South-western Europe has a rich diversity of lacertid lizards. In this study, we evaluated the occupancy patterns and niche segregation of five species of lacertids, focusing on large-bodied species (i.e., adults having >75 mm snout-vent length) that occur in south-western Europe (Italian to the Iberian Peninsula). We characterized the niches occupied by these species based on climate and vegetation cover properties. We expected some commonality among phylogenetically related species, but also patterns of habitat segregation mitigating competition between ecologically equivalent species. We used multivariate ordination and probabilistic methods to describe the occupancy patterns and evaluated niche evolution through phylogenetic analyses. Our results showed climate niche partitioning, but with a wide overlap in transitional zones, where segregation is maintained by species-specific responses to the vegetation cover. The analyses also showed that phylogenetically related species tend to share large parts of their habitat niches. The occurrence of independent evolutionary lineages contributed to the regional species richness favored by a long history of niche divergence. Full article