Few cases of antemortem ovarian torsion and diagnosis have been described in reptiles. This case series reports clinical and ultrasound findings in five adult (aged 1-6 yr) female geckos (three leopard geckos [Eublepharis macularius], one crested gecko [Correlophus ciliatus], and one gargoyle gecko [Rhacodactylus auriculatus]) diagnosed with unilateral ovarian torsion between 2019 and 2023. All animals presented with acute weakness associated with coelomic distension, and one suffered from chronic diarrhea and cachexia. Coelomic ultrasound examination (12-MHz linear probe) revealed signs of bilateral follicular stasis and oophoritis in all cases (heterogenic follicles ≤1.3 cm diameter) associated with a large anechoic periovarian rim and a hyperechoic chord, consistent with twisted ovarian vessels. Blood supply to ovarian structures was not detected using a Doppler flow, and a unilateral ovarian torsion was diagnosed in all geckos. A bilateral ovariectomy was performed under general anesthesia in all five animals. The mass of the excised ovaries varied between 7 to 15 g (12.7-22.2% of body weight). One gecko died 1 d postsurgery; the four remaining animals were healthy 6 mon postsurgery. Gekkonids are unique among reptiles in that they undergo a monoautochronic ovulation (only one follicle is recruited by each ovary during each ovarian cycle); the presence of multiple vitellogenic follicles on each ovary facilitates the diagnosis of follicular stasis. This condition was present in all five geckos and was suspected to have led to ovarian torsion. This case series emphasizes the value of ultrasound examination for antemortem diagnosis of reproductive disorders in reptiles.

Skink, anguid, and pygopod lizards possess an extremely flat skin, imparting a compact and solid body and shining surface that facilitates their slider and/or fossorial movements. The present morphological study, conducted using immunohistochemistry and electron microscopy, has analyzed the microscopical morphology of extremely overlapped scales in different lizards, including species with limb reduction (scincids such as Lerista bougainvilli, Scincella lateralis, Lampropholis delicata) or legless (pygopods such as Lialis burtonis and Delma molleri and the anguid Anguis fragilis). The outer surface of the epidermis shows different micro-structures of the Oberhautchen layer containing corneous beta-proteins (CBPs) with variable immunoreactivity for these proteins. The beta-layer is relatively thick in most of these species, probably in relation to the resistance against strong mechanical forces acting on scales during the movements on harsh substrates. The scincid and anguid lizards also possess and regenerate osteoderms that reinforce scales flatness and mechanical resistance during the serpentiform or fossorial movements of these reptiles. Osteoderms are absent in pygopods. Roundish cells with a granular content are detected in the deep hinge region of scales in Lerista and Lampropholis skinks. Whether these cells may secrete substances that facilitate scale anti-friction and also determine shining of the skin surface remains to be shown.

Soft actuators made of soft materials cannot generate precisely efficient output forces compared to rigid actuators. It is a promising strategy to equip soft actuators with variable stiffness modules of layer jamming mechanism, which could increase their stiffness as needed. Inspired by the gecko\'s the array of setae, bionic adhesive flaps with inclined micropillars are applied in layer jamming mechanism. In this paper, after the manufacturing process of the layer jamming actuator based on the bionic adhesive flaps is described, the equivalent stiffness models of the whole actuator are established in the unjammed and jammed states. And the shear adhesive force of a single micropillar is calculated based on the Kendall viscoelastic band model. The finite element simulation results of two bionic adhesive flaps show that the interlaminar shear stress and stiffness increase with the increase of pressure. The measurement of shear adhesive force show that the critical shear adhesive force of the bionic adhesive material is 3.2 times that of polyethylene terephthalate (PET) material, and exhibit the ability of anisotropic adhesion behavior. The variable stiffness performance of the layer jamming actuator based on bionic adhesive flaps is evaluated by three test methods, and the max stiffness reaches 8.027 N mm-1, which is 1.5 times higher than the stiffness of the layer jamming actuator based on the PET flaps. All results of simulation and experiment effectively verify the validity and superiority of applying the bionic adhesive flaps to the layer jamming mechanism to enhance the stiffness.

UNASSIGNED: This study aims to investigate the urban colonization of the Asian water monitor (Varanus salvator) across its entire range of distribution, addressing the paucity of research on this species in urban ecosystems. The research spans the geographic range of the Asian water monitor, focusing on urbanized areas where the species accumulates more observations (Bangkok, Colombo, Jakarta, Kuala Lumpur and Singapore).
UNASSIGNED: We conducted a systematic review to comprehensively assess the current knowledge of the species\' presence in cities. Additionally, citizen science data from repositories like GBIF (Global Biodiversity Information facility ) were utilized to analyze the distribution patterns of V. salvator in urban environments. To elucidate urban distribution and correct collection biases, observations were weighted by sampling effort, using as a proxy all squamate occurrences available from 2010-2023, including V. salvator.
UNASSIGNED: Despite the widespread presence of the Asian water monitor in numerous cities within its distribution range, the available studies on the topic appear to be scarce. Existing research primarily consists of descriptive reports on diet and behavior. Our findings indicate that V. salvator predominantly colonizes green patches in urban areas, such as parks and small gardens. Larger cities exhibit higher records, potentially due to both permanent populations and increased citizen science reporting.
UNASSIGNED: The Asian water monitor, as the largest lizard with established populations in cities, remains scarcely studied on a broader scale. However, the urban design of each city seems relevant to understand the distribution patterns within each context. Our study highlights the need for further research to explore the ecological and human dimensions associated with the species\' presence in urban environments.

This research focused its interest on the mathematical modeling of the demographic dynamics of semelparous biological species through branching processes. We continued the research line started in previous papers, providing new methodological contributions of biological and ecological interest. We determined the probability distribution associated with the number of generations elapsed before the possible extinction of the population in its natural habitat. We mathematically modeled the phenomenon of populating or repopulating habitats with semelparous species. We also proposed estimates for the offspring parameters governing the reproductive strategies of the species. To this purpose, we used the maximum likelihood and Bayesian estimation methodologies. The statistical results are illustrated through a simulated example contextualized with Labord chameleon (Furcifer labordi) species.

OBJECTIVE: This study describes the composition and infection patterns of macro endoparasites associated with the lizard Phyllopezus periosus.
METHODS: We collected 115 P. periosus over 12 expeditions on the rocky cliffs of the Missão Velha waterfall canyon in northeastern Brazil. Specimens were collected by hand, during active searches conducted between 18:00 h and 23:30 h. The infection patterns were estimated using prevalence, total abundance, and mean intensity of infection for all parasites found.
RESULTS: A total of 4256 parasites were collected from 104 hosts, resulting in an exceptionally high overall prevalence of 90.4%. No significant ontogenetic difference in the prevalence of infection was detected. Although juveniles exhibited a high parasite prevalence their parasite loads were significantly lower compared to adults. Six species of endoparasites were found; among these, the nematode Spauligodon oxkutzcabiensis was the most common endoparasite in the digestive tract, while the pentastomid Raillietiella mottae was the only species found in the respiratory tract.
CONCLUSIONS: Infection rates in Gekkota species appear to correlate with body size, with larger individuals generally exhibiting a higher prevalence. This pattern was also observed across separate populations of P. periosus and other geckos from distinct ecological domains. The dominance of the monoxenous S. oxkutzcabiensis highlights potential transmission mechanisms, suggesting that behaviors such as limb licking after feeding may contribute to its prevalence. The occurrence of Physalopteroides venancioi, Oswaldocruzia sp., Parapharyngodon sp., Physaloptera sp., infecting P. periosus are new records for this host. These findings significantly contribute to the knowledge of host-parasite dynamics in geckos.

The atractid nematode Cyrtosomum penneri is an autoinfective parasite of several lizard species. Intraspecific transmission between hosts appears to occur exclusively through sexual copulation, yet it is unclear how worms are transferred between different host species. Our research aims to test the possibility of oral transmission of C. penneri using experimental infections. The lizards Anolis sagrei, Leiocephalus carinatus, Hemidactylus mabouia, and Agama picticauda were experimentally exposed to C. penneri in 1 of these groups: (1) oral infection using a feces and saline slurry to approximate host coprophagy, (2) oral infection with a large meal to approximate host predation, and (3) venereal infection using a pipette to confirm sexual transmission. Experimental infections to test venereal transmission were successful in A. sagrei, A. picticauda, and H. mabouia, but were unable to establish infections in L. carinatus. In the predation exposures, A. picticauda, A. sagrei, and H. mabouia hosted infections, whereas L. carinatus were uninfected. Finally, coprophagy experimental infections did not result in infections for any species of host. Our study corroborates venereal transmission of C. penneri in multiple species of lizards and establishes predation as an alternative route of infection. Predation as an oral route of transmission may provide C. penneri an opportunity for interspecific transmission that would otherwise be unlikely during host copulation.

Thubunaea acostai sp. nov. is described and illustrated here, based on specimens found in the digestive tract of Liolaemus gracielae in the province of San Juan, Argentina. The new species differs from all other species assigned to Thubunaea by the number of caudal papillae. Thubunaea acostai sp. nov. has 30-31 papillae (12 pedunculated and 18-19 sessile), differing from other Neotropical species such as Thubunaea eleodori with 26 papillae (12 pedunculated and 14 sessile) and Thubunaea parkeri with 20 papillae, all pedunculated. The new species represents the third species for the Neotropics and the second described for Argentina.

Microplastics are a global environmental problem, polluting both aquatic and terrestrial environments. Terrestrial lizards are suitable model organisms to study human-induced pollution in these areas, as they can live in urbanized areas where microplastics are most abundant. Therefore, we analyzed the prevalence of microplastics (MPs) in a common Lacertid lizard, the snake-eyed lizard, Ophisops elegans. We detected MPs in the gastrointestinal tract (GIT) of 33 of 152 specimens from 18 populations. The detected MPs had six distinct polymer compositions, namely Polyethylene terephthalate, Polyacrylonitrile, Polypropylene, Polyethylene, Poly methyl methacrylate and Polyamide. The majority of these MPs were fiber-type and the dominant color was navy blue. The lengths of MPs varied from 37 to 563 μm, with an average length of 175 μm. MPs were detected in the GITs of 43% of juveniles (n = 7), 30% of males (n = 105), and 18% of females (n = 40), with a mean of 0.27 per specimen. Furthermore, we found that microplastic densities varied with habitat distance from human settlements, supporting the theory that high levels of microplastic contamination are associated with extensive anthropogenic activity.

Fossil identification practices have a profound effect on our interpretation of the past because these identifications form the basis for downstream analyses. Therefore, well-supported fossil identifications are necessary for examining the impact of past environmental changes on populations and communities. Here we apply an apomorphic identification framework in a case study identifying fossil lizard remains from Hall\'s Cave, a late Quaternary fossil site located in Central Texas, USA. We present images and descriptions of a broad comparative sample of North American lizard cranial elements and compile new and previously reported apomorphic characters for identifying fossil lizards. Our fossil identifications from Hall\'s Cave resulted in a minimum of 11 lizard taxa, including five lizard taxa previously unknown from the site. Most of the identified fossil lizard taxa inhabit the area around Hall\'s Cave today, but we reinforce the presence of an extirpated species complex of horned lizard. A main goal of this work is to establish a procedure for making well-supported fossil lizard identifications across North America. The data from this study will assist researchers endeavoring to identify fossil lizards, increasing the potential for novel discoveries related to North American lizards and facilitating more holistic views of ancient faunal assemblages.