Snout-vent Length Research Articles

Morphological characterization and sexual dimorphism of saw-scaled viper (<em>Echis</em>: viperidae: ophidia) population in Sri Lanka

The Saw-scaled vipers (SSV) of the genus Echis (Viperidae: Ophidia) primarily inhabit tropics. In Sri Lanka, E. carinatus is densely populated in the Northern Province where they account for over 50% of the local snakebites. Although it was initially reported as a unique Sri Lankan subspecies named E. c. sinhaleyus, its existence was later questioned, urging the need for more detail studies. The present study examined morphological characters and sexual dimorphism in 30 specimens (17 males and 13 females) collected from Kilinochchi and Jaffna Districts in the Northern Province, using 12 mensural and 17 meristic traits, updating Deraniyagala’s report of 1951. Results showed that the adult females have longer snout to vent length (SVL) than that of males (280.34±43.32 vs. 240.88±27.03), revealing a positive sexual dimorphism index. Males had a greater TL/SVL ratio (x̄̄=13.89±0.68) than that of females (x̄̄=10.65±085). ANCOVA test retrieved most accurate and an independent significant effect of ‘sex’ on TL while SVL serving as the covariate. Males and females shared consistent meristic characters, except for number of dorsal scales at the lower part of the body, ventral and sub-caudal scales. There were more ventral scales in females (145.54±3.31) than that of males (138.41±4.08), and sub-caudal scales were higher in number in males (28.94±1.85) than that of females (25.85±2.82). Although, there were some colour pattern variations of the specimens, (head pattern and ventral pattern), they were not sex-associated and distributed evenly between males and females. This is the first study to illustrate the detail morphometric characters; mensural traits; meristic traits, and color patterns and to demonstrate the sexual dimorphism in the SSV from Sri Lanka, with noticeable differences in the snoutvent length (SVL), tail length (TL), ventral scales, and sub-caudal scales between male and female.

The Composition and Function of Intestinal Microbiota Were Altered in Farmed Bullfrog Tadpoles (Aquarana catesbeiana) during Metamorphosis

The bullfrog Aquarana catesbeiana is one of the main farmed frog species in China, with a low overall survival of farmed bullfrogs from hatching to harvest since bullfrog tadpoles are fragile during the metamorphosis period. The intestinal bacterial community can play crucial roles in animal development; however, little is known about the alteration of the gut microbial community of A. catesbeiana during metamorphosis. The present study used 16S rRNA amplicon sequencing to investigate the intestinal bacterial community in A. catesbeiana at four distinct developmental stages. Moreover, we determined the bullfrog’s body morphological parameters and the intestine histology at different developmental stages. The results showed a reduction in the total length and snout–vent length of A. catesbeiana during metamorphosis. The intestinal microbial composition of A. catesbeiana exhibited variation throughout the process of metamorphosis. The terrestrial stage showed shifts in the bacterial composition compared to the aquatic stages, including a reduction in Bacteroidetes and an increase in Firmicutes. Furthermore, the presence of Prevotella, Bifidobacterium, Leucobacter, Corynebacterium, Bulleidia, Dorea, Robinsoniella, and Clostridium in A. catesbeiana metamorphosis appears to be mainly related to the host’s epithelial cells’ height and total body mass. The results indicated that the intestinal microbial composition changed with the bullfrog–tadpole metamorphosis. The genera of Prevotella, Bifidobacterium, Leucobacter, Corynebacterium, Bulleidia, Dorea, Robinsoniella, and Clostridium might be potential probiotics.

Environmental Drivers of Local Demography and Size Plasticity in Fire Salamanders (Salamandra salamandra).

Conspecific amphibian populations may vary widely in local demography and average body size throughout their geographical range. The environmental drivers of variation may reflect geographical gradients or local habitat quality. Among fire salamander populations (Salamandra salamandra), local demography shows a limited range of variation because high concentrations of skin toxins reduce mortality from predation to a minimum, whereas average adult body size varies significantly over a wide range. This study on four neighboring populations inhabiting the catchments of low-order streams in the upper middle Rhine Valley (Koblenz, Germany) focuses on the identification of local environmental drivers of variation in age and body size. I collected 192 individuals at two localities per stream, measured snout-vent length, clipped a toe for posterior skeletochronological age determination, and released salamanders in situ again. Populations were similar in age distribution. Local habitat quality accounted for a significant proportion of demographic variability, mediated by the impact of landscape-induced mortality risk, including roads and agriculture. Still, the main effect of variation in habitat quality was on adult body size, the result of growth rates of aquatic larvae and terrestrial juveniles. Larvae exposed to non-lethal heavy metal contamination in streams developed into smaller juveniles and adults than clean-water larvae, providing evidence for carry-over effects from one stage to another. The generally small average adult size in the Rhine Valley populations compared to those in other parts of the distribution range indicates the action of a still unidentified environmental driver.

Effects of anthranilic diamide insecticides on metamorphosis in the common toad Rhinella arenarum (Hensel, 1867) at concentrations found in aquatic environments

ABSTRACT Anthranilic diamides (AD) are a modern class of insecticides used as alternatives to pyrethroids and neonicotinoids, particularly against lepidopteran pests. Despite their widespread use and presence in surface waters, little is known regarding their effects on amphibians. The aim of this study was to examine the effects of environmentally-relevant concentrations of AD insecticides chlorantraniliprole (CHLO) and cyantraniliprole (CYAN) on metamorphosis of the toad Rhinella arenarum. Tadpoles were exposed to CHLO or CYAN at concentrations ranging from 5 and 5000 µg/L from stage 27 until metamorphosis completion. Both insecticides produced a non-monotonic acceleration of the time required for individuals to progress through development and a decrease in the proportion of individuals completing metamorphosis, although a delay in metamorphosis was also observed at 5 µg/L of CHLO. Snout-vent length and body weight of metamorphosed toads were not markedly affected by either insecticide. CHLO was more toxic than CYAN, with a lowest observed effect concentration (LOEC) for CHLO on time to metamorphosis defined as 5 µg/L compared to 5000 µg/L for CYAN. The LOEC for reduced metamorphic success defined as 50 µg/L for CHLO compared to 500 µg/L for CYAN. As most effects occurred after stage 39, when metamorphosis depends upon thyroid hormones, it is conceivable that that AD insecticides act as endocrine disruptors. These findings suggest that contamination of surface waters with CHLO and CYAN may disrupt amphibian development in the wild and warrant further research to investigate the possibility of endocrine-disruption by ADs.

Assessing Species-Level Identification of Some Cryptic Frog Species of Bangladesh Using 16s and 12s Rrna Genes

In recent years, a number of new and undescribed anuran species are being discovered at a very fast rate in South and Southeast Asia. With the revelation of more and more species that were previously considered to be some other species, accurate identification of these morphologically cryptic anurans based on morphology alone have become difficult. In this study, we attempted specieslevel identification of 15 frog specimens belonging to the families Dicroglossidae and Microhylidae of Bangladesh by analyzing their 16S and 12S rRNA gene sequences. The collected specimens were successfully identified to be belonging to eight different species, namely Fejervarya dhaka, F. asmati, F. pierri and F. orissaensis; Euphlyctis kalasgramensis and Euphlyctis sp.; Microhyla berdmorei and M. mymensinghensis using BLAST and maximum likelihood analyses. In some cases the frog samples showed morphological resemblance but after molecular analysis they were found to be different and in another case morphologically distant samples were found to be molecularly similar. For example, two of the specimens (ESP 01, ESP 02) turned out to be E. kalasgramensis at molecular analysis, however, did not match with the morphological and morphometric descriptions (specially snout-vent length) described previously. Moreover, a species is suspected to be still undescribed and another species namely M. berdmorei was thought to be absent in Bangladesh which has been recorded in our study. Thus, morphological ambiguity strengthens the urge for molecular analysis for proper identification. Dhaka Univ. J. Biol. Sci. 33(2): 27-52, 2024 (July)

Methylmercury Concentrations More Strongly Associated With Trait Variation Than Food Web Position in Plethodontid Salamanders.

Salamanders serve as bioindicators of mercury (Hg) in both terrestrial and aquatic habitats and are an important link in the food web between low-trophic prey and higher-trophic predators. We investigated the drivers of methylmercury (MeHg) exposure in three common plethodontid salamander species in New York State, USA, including comparisons among regions, habitat types (terrestrial and semiaquatic), and color morphs of Plethodon cinereus (striped and unstriped). Nonlethal tail samples were collected from one terrestrial species (P. cinereus) and two semiaquatic species (Eurycea bislineata and Desmognathus spp.) in the Adirondack Mountains (ADK) and the Finger Lakes National Forest (FLNF) regions. Samples were analyzed for MeHg and stable isotopes, including δ15N and δ13C which are proxies of trophic position and diet, respectively. Despite elevated biota Hg concentrations typically found in the ADK, salamander MeHg concentrations did not differ by region in the terrestrial species and one of the semiaquatic species. In addition, diet and trophic level did not explain MeHg exposure in salamanders. Semiaquatic salamanders exhibited higher MeHg concentrations than terrestrial salamanders in the FLNF only. Within species, only snout-vent length predicted MeHg concentrations in E. bislineata with few other variables significant as predictors of MeHg concentrations in path models. Among P. cinereus individuals in the FLNF, the striped morph had greater MeHg concentrations than the unstriped morph, and food web tracers were not different between morphs. Overall, New York State salamander Hg concentrations were elevated compared to other locations where these species are present. The present study establishes baseline Hg data in salamanders for future assessments of changes in Hg bioavailability to forests of New York State. Environ Toxicol Chem 2024;43:2045-2057. © 2024 SETAC.

A new species of colorful Platypelis (Amphibia: Microhylidae) from the Tsaratanàna and Bemanevika massifs in northern Madagascar

Frogs of the genus Platypelis are known to have their center of species richness in the mountain massifs of northern Madagascar. We here formally describe a new species of Platypelis from this region. Platypelis saikamavo sp. nov. has been known for over 20 years but its taxonomic identity has only recently been robustly clarified as a result of ongoing taxonomic revisions of other Platypelis species. The new species is known from rainforest on the Tsaratanàna Massif and Bemanevika, at elevations of 1000–1530 m above sea level. It is characterized by an isolated phylogenetic position and is genetically highly divergent, with an uncorrected pairwise distance ≥4.5% in the mitochondrial 16S rRNA gene to all other nominal species of Platypelis. It has a unique combination of morphological and chromatic character states such as a relatively large body size of 28–31 mm in snout–vent length, distinct superciliary tubercles, and bright yellow color around the forelimb insertion and on the posterior abdomen where this color extends in the form of flash marks onto the inguinal region.

Anuran responses to urbanization: evaluating life history traits of Rhinella arenarum in urban wetlands

Abstract Wetlands are unique ecological environments capable of harboring high biodiversity. However, urbanization can degrade, eliminate, or transform these habitats. Although amphibians utilize habitats created by humans in urban landscapes, few studies have investigated the influence of the habitat quality on the life history of anurans. We assessed life history traits such as snout-vent length (SVL), body condition, and reproductive investment in the South American common toad Rhinella arenarum, to determine whether urbanization is harmful or beneficial to this species. We sampled wetlands with different levels of urbanization in Río Cuarto city, Córdoba, Argentina. We recorded males with lower SVL in medium urbanized wetlands and those with the highest SVL in both low and high urbanization categories, similar to what was found for body conditions with males with low body conditions inhabiting wetlands with a medium degree of urbanization. In females, lower SVL was recorded in medium urbanization and highest SVL in high and low urbanization. It is observed that females recorded in highly urbanized wetlands have a very low body condition. The reproductive investment parameters were not significantly different, but we observed an association between a greater number of eggs and clutch size with wetlands of low urbanization. These results show a variability of responses of R. arenarum to urbanization, which could be due to phenotypic plasticity in its life history parameters, allowing it to inhabit urban areas. Continuous monitoring of the species in these wetlands is needed to determine if these biological responses are temporary or persistent.

Prevalence of injuries in a Caiman crocodilus chiapasius (Bocourt 1876) population from the South Pacific coast of Mexico

ABSTRACT Crocodilians injuries are indicators of their health and social interactions. We analyzed the prevalence and distribution of injuries in spectacled caiman (Caiman crocodilus chiapasius) from the Biosphere Reserve of La Encrucijada (BRLE) in relation to the habitat, size, and sex of individuals. We collected data on injuries in caimans captured during nocturnal surveys (2014–2022) in the estuary and swamps of the BRLE. We determined the sex of each caiman, measured their snout–vent length, and registered the type of injury and body region where injuries were detected. From all records, 102 of 301 caimans (33.9%) presented injuries and they were more likely to be injured in the estuary than in the swamps, probably due to the presence of a larger sympatric crocodile species in the estuary (Crocodylus acutus). Sex had no effect on the proportion of injured individuals, but larger caimans have a higher probability of being injured than smaller ones, explained by an ontogenetic change in the individuals’ behaviors. Habitat, sex, and size class of individuals do not influence the number of injuries on different body regions. The tail was the most injured body region (17.6% of individuals), followed by the abdomen (13.0%), back (12.6%), head (9.6%), and extremities (4.0%).

How anatomy influences measurements of snakes.

Anatomy compromises the precision and accuracy of measurements made of the body length and head size of live snakes. Body measures (snout-vent length, SVL) incorporate many synovial intervertebral joints, each allowing flexion and limited extension and compression. Radiographs of the trunk in 14 phylogenetically diverse species in resting and stretched conditions combined with dissections and histological analysis of intervertebral joints show that the synovial nature of these joints underlies the variance in SVL measures. Similarly, the ubiquity and variety of viscoelastic tissues connecting mobile snout and jaw elements of alethinophidian snakes underlie variances in length and width measures of the head. For the overall size of the head and jaw apparatus, the part that can be most easily and relatively precisely measured for many snakes is the mandible because it has only one mobile joint. As to accuracy, the anatomy of intervertebral and cranial joints supports the hypothesis that in living snakes, the head and trunk have no exact size.

Assessing ecological impacts of agricultural practices using frogs as bioindicators

Abstract. Kurnianto AS, Kusumawati A, Widjayanthi L, Wulanjari D, Ibanah I, Majid MAA, Puspitasari DA, Priambodo B. 2024. Assessing ecological impacts of agricultural practices using frogs as bioindicators. Biodiversitas 25: 3208-3215. The rapid intensification of agriculture, driven by the increasing global demand for food, heavily relies on chemical inputs like pesticides and synthetic fertilizers. While these practices enhance production, they pose significant challenges to ecological balance and environmental health. Biomonitoring efforts have been developed to detect and evaluate the chemical pollutants' impact on the environment, employing species like the rice field frog (Fejervarya limnocharis Gravenhorst 1829) as bioindicators. This study aimed to assess the reliability of rice field frogs' liver gravimetry and morphology as biomonitoring tools using various analytical methods. Samples were collected from rice fields managed both organically and conventionally to analyze liver weight, individual weight, and Snout-Vent Length (SVL). This analysis was conducted to understand the environmental effects on these physiological parameters. Statistical analysis revealed significant differences between the two management practices, indicating environmental conditions notably influence the frogs' physiological parameters, highlighting their potential as bioindicators for chemical pollutants. The findings underscore the need for further research to optimize biomonitoring methods for sustaining environmental health and agricultural practices. This study contributes to the development of more sophisticated and effective biomonitoring methods, supporting sustainable agricultural practices and environmental mitigation strategies.

Reproductive output in a small Mediterranean lizard, the western three-toed skinks Chalcides striatus

Abstract The Western Three-toed Skink (Chalcides striatus) is a viviparous species found in arid Mediterranean climates. Using artificial shelters, we captured five pregnant females (snout vent length = 139.2 ± 7.9 mm [SD], 131 to 150 mm; total length = 286.0 ± 9.6 mm, 275 to 292 mm [N = 3, two females with damaged tails]); body mass 15.72 ± 3.89 g, 11.55 to 19.88) and kept them in captivity until parturition. Mean litter size and litter mass were 6.2 ± 1.3 (5 to 8 neonates) and 3.85 ± 0.88 g (2.99 to 5.13 g), respectively. Mean neonatal size and mass were 81.2 ± 4.1 mm (total length = 70 to 90 mm, N = 26) and 0.62 ± 0.07 g (0.49 to 0.82 g, N = 31), respectively. On average, the relative litter mass represented 32 ± 3% (29% to 36%) of the postpartum female body mass. The estimated mass of water lost at birth (total mass loss at parturition minus litter mass) was 0.37 ± 0.39 g (0.00 to 0.98 g), representing 10 ± 8% (0 to 26%) of the individual neonate mass. This low value is in line with that expected for viviparous squamates from arid climates, which is much lower than that observed in oviparous or in viviparous squamates from temperate climates. These results help to fill a gap, as the reproductive output of Chalcides striatus has been poorly documented, but mostly because the importance of extraembryonic water mass has been neglected.

A new glassfrog of the genus Centrolene (Amphibia, Centrolenidae) from the Subandean Kutukú Cordillera, eastern Ecuador

We describe a new species of Centrolene from the Subandean Cordillera of Kutukú in southeastern Ecuador. The new species differs from all other glassfrogs by the combination of the following characters: presence of processes of vomers but without vomerine teeth; humeral spines in males; dorsum green with light green dots and without dark marks; dorsal skin with abundant tubercles; all visceral peritonea translucent (except for pericardium); and small body size (snout-vent length 21.5–21.9 mm in adult males). The new species is sister to Centrolene camposi from the Western Cordillera of the Andes of southwestern Ecuador, and together they form a clade with C. condor from the Subandean Cóndor Cordillera in southeastern Ecuador. Our time tree suggests that the new species originated at the end of the Pliocene. In addition, we present new information for C. zarza, expanding its geographic range across the southeastern Andes and the Kutukú and Cóndor cordilleras, amending its definition and diagnosis, and offering new information on its natural history and extinction risk. We also discuss the taxonomic status of Ecuadorian populations reported as C. huilensis and conclude that they are C. muelleri based on their close phylogenetic relationships and morphological similarity to samples of C. muelleri from Peru. Centrolene huilensis is a valid species and not closely related to C. muelleri.

Effects of road salt, egg predation and alterations to the egg-mass jelly layers on the embryos of spotted salamander Ambystoma maculatum

Road de-icing salt has been used to make winter driving safer. However, its eventual drainage into adjacent water bodies has caused detrimental effects on organisms in those aquatic communities, including amphibians. We used the spotted salamander Ambystoma maculatum as a model species and examined whether there would be additive or interactive effects of road salt, egg predation from wood frog Lithobates sylvaticus tadpoles, and alteration to egg-mass jelly layers on the hatching rate, incubation period, snout-vent length (SVL) and developmental stage of hatchlings. We found neither main nor interactive effects of salt on the measured traits, which contradicts some of the previous studies. The other body of previous studies, however, showed observational and experimental evidence that amphibian populations became locally adapted to saline water. Given the roadside origin of our study animals, our negative results provide insight into the ubiquity of local adaptation to saline water among amphibian populations. We also found that egg predation and the presence of egg-mass jelly layers negatively affected the incubation period, SVL, or development in the predicted manners based on the O2 demand-supply balance within egg masses. These responses might be altered by dissolved salt if populations naive to freshwater salinisation were exposed to saline water. Keywords: aquatic pollution, community ecology, conservation, larval amphibians, Lithobates sylvaticus

Predator morphology affects prey consumption: evidence from an anuran population in subtropical wetlands

Morphology and diet are key factors in the ecology of organisms, determining aspects of the natural history and evolution of the species. In this work, we evaluated the diet-morphology relationship in an anuran population, measuring the influence of morphological traits on the variation in the diet of individuals of Leptodactylus luctator. For this purpose, we collected individuals from a natural grassland habitat in southern Brazil. We analysed the stomach content of individuals and classified the consumed food items up to the classification level of order. We also measured four morphological traits per individual of L. luctator: distance between eyes, relative limb length, relative mouth width (gape) and snout-vent length. We applied Linear Mixed Effect Models to evaluate the relationship of anuran morphological traits, number of prey taxa and volume of consumed prey. We tested the hypothesis that the configuration of predator morphological traits determines variations in prey consumption patterns. Our results indicate that the body size of L. luctator was not directly related to the diet composition but the individuals’ gape is directly and positively related to the number of consumed taxa. This suggests that gape limitation could be a limiting factor in prey selection. The capacity to consume a wide variety of prey taxa could be an advantage in unpredictable environments, especially those with great daily thermal amplitudes such as the subtropical Brazilian grasslands. Keywords: Leptodactylus luctator, diet, amphibian, ecomorphology, functional ecology

The growth in juvenile spectacled caimans at The Lost World of Tambun Malaysia

The spectacled caiman needs to be better studied, and its basic life history needs to be explored. Growth rates and changes in growth with age and size are essential life history characteristics. This study aimed to determine the growth rate of juvenile spectacled caimans in captivity and understand the factors that affect the growth rate of juvenile spectacled caimans. Fourteen juvenile spectacled caimans were used in the present study. The study shows that the growth rate of all the juvenile spectacled caimans varied, where specimens such as Delta and 9th Dot had the highest growth rate in terms of weight at 0.98 g/day and 0.89g/day, respectively. However, Little Foot had the lowest growth rates in snout-vent length and weight parameters at 0.03 cm/day and 0.08 cm/day. This study shows that the growth rate of juvenile spectacled caimans that dominance has a strong effect on the growth rate of juvenile spectacled caimans in captivity. Other factors that could be affected were social behavior, feeding behavior, and natural selection.

Are Bergmann's and Jordan's rules valid for a neotropical pitviper?

AbstractMorphological variation along the spatial distribution of species has been extensively investigated in ecological studies, and several ecogeographical rules explore the relationships between morphological traits and the environment. Many morphological traits are correlated, providing an opportunity to evaluate the validity of multiple ecogeographical rules simultaneously. Bergmann's rule predicts that endothermic animals in colder locations are larger than those in warmer locations. Jordan's rule predicts that fish from colder locations have more vertebrae than those from warmer locations. We tested the validity of Bergmann's and Jordan's rules for the neotropical lancehead snake Bothrops jararaca. We evaluated three morphological characters of 342 specimens: number of ventral scales (proxy for vertebrae number), snout–vent length (a linear measure of body size) and stoutness (volumetric body size). We implemented spatial regressions to evaluate the variation of morphological dimensions using climatic predictors: the minimum temperature and evapotranspiration. SVL was poorly related to minimum temperature and evapotranspiration. However, stouter individuals were found in colder places with greater evapotranspiration, following Bergmann's rule and the water conservation hypothesis. Individuals in warmer locations also had a greater number of ventral scales, reversing Jordan's rule. We showed that different selective pressures act on different morphological dimensions. Although stoutness follows Bergmann's rule, its variation would arise from an energy storage demand rather than heat conservation. Also, stoutness variation along evapotranspiration gradients could represent a mechanism to avoid hydric stress in environments with considerable climatic variations. The variation in vertebrae number along temperature gradients could be related to ecological factors and foraging. We highlight that physioecological mechanisms to deal with climatic variation and ecological aspects could be identified in snakes through intraspecific analyses, contrasting with interspecific studies that can hardly detect general trends. Due to different environmental effects on body size, we shed new light on the importance of exploring multiple morphological dimensions in macroecological studies.

Description of a new sandstone-dwelling species of genus Cnemaspis (Sauria: Gekkonidae) from Gunung Santubong National Park, southwestern Sarawak, Malaysia

A newly discovered sandstone-dwelling species of the rock gecko, genus Cnemaspis, is described from Santubong National Park, 25 km north of Kuching, southwestern Sarawak, Malaysian Borneo. Molecular phylogenetic analysis confirmed that Cnemaspis puterisantubongae sp. nov. is closely related to other Cnemaspis species in southwestern Sarawak, except for C. kendallii, although these relationships remain unclear. The new species differs from closely related species in having a moderate snout–vent length of up to 66.7 mm; 10–14 precloacal pores in males; 9–14 obviously-convex precloacal pore-bearing scales in females; enlarged, smooth, flat median subcaudal scales; sharp-edged, broad black markings on the trunk dorsum; and a black–gray banding pattern on the posterior part of the original tail, with white median subcaudal scales in males. This discovery of this new species from Santubong National Park, which is highly accessible due to its proximity to Kuching, highlights the need for extensive inventory surveys throughout the national parks of Sarawak.

Life-history evolution in the orange-tailed skink populations living in different climates.

The life-history traits of ectothermic animals can be influenced by many abiotic factors, including climate. As an ectothermic species, we questioned whether the life-history characteristics of the orange-tailed skink (Eumeces schneiderii) populations differ between two different environments/climates. Our findings showed that the average body size of lizards living in the Mediterranean climate zone was higher than those in the continental climate zone. However, although Mediterranean population had higher mean values regarding average age, there was no discernible difference between the two climate zone populations. When considering all populations collectively, it has been discovered that the species' maximum lifespan is 18 years. Body size notably increased with age in both populations. Through the utilization of the von Bertalanffy equation, the anticipated growth parameters portrayed a highly accurate connection between age and snout-vent length. In conclusion, lizards living in habitats characterized by milder Mediterranean climates were found to have larger body sizes than continental populations, but both populations were comparable in terms of mean age. This difference can be explained by several factors, including activation time, temperature, precipitation, food abundance, and the presence of predators.

Toe pad morphology and adhesion in the miniaturized gecko, Chatogekko amazonicus (Gekkota: Sphaerodactylidae).

Chatogekko amazonicus is a miniaturized gecko from northern South America and is among the smallest of toe pad bearing lizards. The toe pads of C. amazonicus are miniscule, between 18% and 27% of the plantar surface area. We aimed to investigate the relationship between adhesive toe pad morphology, body size, and adhesive capabilities. Using scanning electron microscopy, we determine that the adhesive pads of C. amazonicus exhibit branched setae similar to those of other geckos, but that are generally much smaller. When compared with other gecko taxa, we show that C. amazonicus setae occupy a similar range of seta length: snout-vent length ratio and aspect ratio as other gekkonoid species (i.e. Gekkonidae, Phyllodactylidae, and Sphaerodactylidae). We demonstrate that C. amazonicus-even with its relatively small toe pads-is capable of climbing a smooth glass surface at a nearly vertical angle. We suggest that sphaerodactylids like C. amazonicus offer an excellent system for studying toe pad morphology and function in relation to miniaturization.