We studied the sexual dimorphism and reproductive cycle of Amphisbaena brasiliana, based on specimens from the municipality of Santar & eacute;m, Par & aacute; state, Brazil, and tested whether precipitation affects the cycle. We accessed and analysed 143 individuals (73 males, 70 females), deposited in scientific collections between 1999 and 2021. We analysed: snout-vent length (SVL), testicular length, width and height, condition of the ductus deferens (convoluted or non-convoluted), diameter of the ductus deferens in the medial and distal portion, condition of the oviducts (convoluted or non-convoluted), length of the largest follicle and number of primary and secondary follicles (vitellogenic follicles). The SVL of females ranged from 149.10-363.11 mm, with 46 specimens (66%) being mature (smallest adult female = 246.46 mm). Male SVL ranged from 123.31-337.26 mm, with 42 (58%) being mature (smallest adult male = 242.0 mm). The sample does not present significant variation in sexual dimorphism analysed in SVL (Mann-Whitney: P = 0.932). Testicle volume and ductus deferens diameter varied seasonally, with the highest values recorded from August to December, during the low rainfall period. Spermatozoa were recorded in the ductus deferens during the low rainfall months in the region, especially in September, when we observed more individuals with ductus deferens convoluted, which may indicate spermatozoa storage. The testicular volume and the diameter of the ductus deferens in the medial and distal portions are related to the period of lower precipitation (ANOVA: P = 2.1 x 10-5; P = 5.18 x 10-6; P = 1.56 x 10-5, respectively). We recorded oviductal eggs in one specimen in December, in addition to the record of vitellogenic follicles in September, October and December, which allows us to interpret a peak of development in the period of lower precipitation, coinciding with the results for males of the species. Our results suggest that the reproductive cycle of the population of A. brasiliana analysed may be influenced by regional rainfall, being seasonal.
The Boulenger's spiny frog Quasipaa boulengeri G & uuml;nther, 1889, is known from only Vietnam and China. It was listed as Vulnerable (VU) in the IUCN Red List and as Endangered (EN) in Vietnam Red Data Book. Knowledge about natural history of this species is virtually lacking. In this study, we analysed the diet of Q. boulengeri based on stomach contents of frogs collected from Cao Bang and Ha Giang Provinces, northern Vietnam. In addition, we also compared food contents between sexes and seasons. We found a total of 892 prey items belonging to 30 prey categories, including 11 orders of insects and four prey categories of invertebrates. There were no positive correlations between the body size of frogs and the minimum prey volume, while there were correlations between the body size of frogs and maximum prey item volume, mean prey item volume and total prey volume. The most important prey groups of Q. boulengeri were Blattidae (IRI = 40.58%), followed by Acrididae (9.27%), other Coleoptera (7.41%) and Tettigoniidae (4.95%). There was an overlap of 67.39% in the diet between males and females. Despite differences in diet compositions between the sexes, Blattidae, beetles and Acrididae make up a majority of prey for all of them. We also compared diet composition between seasons, with a higher number of prey categories recorded in the rainy season (28) than the dry season (15).
Living caecilian are apodal amphibians that present mainly fossorial and secretive habits, making the usual sampling methods ineffective. Therefore, data on the species and their ecology are scarce. In the Atlantic Forest, there are only 13 species, and anecdotal information is available for just three. The Metropolitan Region of S & atilde;o Paulo is highly fragmented, resulting in local extinction of several species. The first record of caecilians on S & atilde;o Paulo, the largest megalopolis in South America, was in 1905, whereas the last record dates back to 1960. Herein, we report the discovery a Luetkenotyphlus brasiliensis population at Parque da Previd & ecirc;ncia, a small urban park in S & atilde;o Paulo, with vegetation in the primary stage of succession. This park is the smallest Atlantic Forest remnant housing caecilians, and surprisingly, it shows the third largest relative abundance of individuals ever registered in this forest fragments for species conservation.
The Lao sucker frog Amolops cremnobatus is known from Laos and Vietnam while the chloronate huia frog Odorrana chloronota has been recorded from Bangladesh, China, India, Laos, Myanmar, Thailand and Vietnam. However, the diet of the two species is still poorly understood. In this study, we investigate the diet composition and niche overlap in the two species living in sympatry at three streams in Vu Quang National Park, Ha Tinh Province, Vietnam. We use the stomach-flushing method to obtain the stomach contents of 83 individuals, including 51 of A. cremnobatus and 32 of O. chloronota. In total, 21 prey categories from 101 food items of invertebrates, and 18 prey categories from 103 food items of invertebrates are identified in the diet of A. cremnobatus and O. chloronota, respectively. Generally, A. cremnobatus consume more diverse prey types than those taken by O. chloronota, and beetles, cockroaches, grasshoppers and crickets represented the most important prey categories in both species. Our results also strongly corroborate the gape hypothesis by demonstrating that O. chloronata with a larger body size can ingest both larger prey items and greater food volumes. Furthermore, our findings show that body size and foraging behaviour play a significant role in selecting prey categories between the sympatric frog species.
Taxonomic and spatial biases limit the understanding of biodiversity patterns, particularly in the Neotropics, with consequences in systematics, biogeography and conservation. Here, we address the impact of these biases by focusing on the widespread species Trachycephalus typhonius. Despite its common occurrence across its range, misidentifications and cryptic diversity have obscured its true phylogenetic and biogeographic histories. Through extensive field sampling and molecular analysis of cis-and trans-Andean localities, we revealed substantial genetic divergence within T. typhonius, which suggests the presence of multiple cryptic species. The samples from Orinoquia (cis-Andes) and Magdalena Valley (trans-Andes) in Colombia, differ from T. typhonius sensu stricto in Guyana. At least three lineages were observed for T. typhonius across the continent, suggesting a complex diversification pattern shaped by major Neotropical barriers. Our results show the influence of both Andes and Amazon-Orinoquia on the phylogeographic structure and provide insights into the biogeographic history of T. typhonius sensu lato. We discuss the importance of addressing taxonomic and spatial biases, and highlight how geographic barriers and historical processes have influenced diversification in the Neotropics. Our findings illustrate the need for comprehensive sampling and molecular studies for 'common' species, to unravel hidden diversity, which is crucial for accurate biodiversity assessments, understanding evolutionary processes, refine biogeographic models, reassess species distributions and inform conservation strategies. Este resumen traducido al espa & ntilde;ol est & aacute; disponible en supplementary materials.
Several animals advertise their escape performance toward potential predators and convey their unprofitability as prey by exhibiting pursuit-deterrent displays. Foot shakes, which are exhibited by lizards in response to potential predators, are considered as a pursuit-deterrent signal. This pursuit-deterrent signal is thought to be either perception advertisement, indicating the detection of a predator, or quality advertisement, informing the individual's condition. However, it remains unclear what foot shakes advertise to predators. To address this, we conducted a field experiment using the Japanese grass lizard Takydromus tachydromoides, which is known to perform foot shakes. To simulate a predator, we approached the lizards, and measured our distance from the lizards when first spotted (starting distance) as well as the distance between the lizards and us when they fled (flight initiation distance). We also recorded the presence or absence of foot shakes and their distance from us when they initiated the display (display distance). Tested lizards were captured whenever possible and snout-vent length (SVL), sex and body temperature (Tb) were recorded. In 151 approaches, 43 lizards exhibited foot shakes. Approximately half of the lizards displayed foot shakes with display distance between 1 m and 2 m, but none at closer distance. These results align with those observed in foot shakes of other lizards, which are considered as a pursuit-deterrent signal, and are consistent with pursuit-deterrent theory. SVL and Tb had a positive correlation with the probability of foot shakes, and males performed foot shakes more frequently than females. Because SVL and Tb are well known to influence the escape performance of lizards, and sex potentially influences the performance, our results suggest that foot shakes of T. tachydromoides advertises the quality of the lizard rather than the perception of predators.
Amphibians are particularly vulnerable to anthropogenic habitat modifications. Nonetheless, some species are tolerant and persist in modified sites due to unique functional traits. We evaluated how environmental variables (structural, climatic and water physicochemical) derived from anthropogenic modifications structure communities of amphibians from a functional perspective in the Sierra Madre del Sur, Mexico. We sampled 34 sites with varying degrees of habitat modification and classified the anuran community in five functional groups. Redundancy analysis and zero-inflated negative binomial generalised linear mixed models were used to evaluate the relationship between abundance (number of individuals per functional group) and the environmental variables. Results support that community structure and abundance are determined by the ecological preferences and diversity of functional traits of the species. Positive relationships prevailed between abundance and variables of water quality for anurans with rapid development, and humidity for anurans with direct development. Aggregation of forest patches and bare soil areas favoured groups with medium to large arboreal and terrestrial anurans, while these were negatively impacted by agriculture areas. Functional groups with higher abundance where water bodies exhibited certain physicochemical toxic levels were associated with the arrangement and composition of patches of different land uses. We highlight the importance of considering functional groups and landscape variables for understanding the community structure and habitat use of anurans. Specifically, for the anthropogenic landscapes studied, considering key environmental variables that allow sustaining the species' functional traits is essential, with emphasis on an adequate management of water bodies, to establish effective conservation measures.
The Critically Endangered red-crowned roofed turtle Batagur kachuga is a large riverine turtle found in the Gangetic Plain of Northern India; a habitat specialist, it nests exclusively on sandbanks. We examined female nest site selection based on a suite of physical environmental factors. Data were collected from sandbanks within the species range. Known nest sites were sampled for variables defining nest site size, position, moisture content, slope angle, adjacent water depth, pH and substrate particle size composition, and similar data were collected from analogous positions on unused banks. In addition to summarising variables for nest sites to characterise their physical characteristics, we employed a Principal Component Analysis (PCA) to handle multicollinear data, followed by logistic regression to examine the influence of variables on nest site preferences. Among five detected PCA dimensions, one, primarily influenced by substrate moisture, particle size, slope angle and adjacent water depth, was a significant predictor of nest site selection. This study enhances the understanding of nesting habitat preferences for this turtle, offering insights for its management and conservation efforts.
Chelonians belong to the class Reptilia and include turtles, tortoises and terrapins which primarily inhabit freshwater, brackish, coastal and terrestrial ecosystems. More than 50% of the 364 known living species of turtles and tortoises are under the Threatened category which are facing a perilous situation. They encounter various pathogenic and non-pathogenic bacteria and fungi in the sand and soil of nesting habitats while laying their eggs. In comparison to the non-nesting beaches, sea turtle nesting beaches possess significantly higher nutrient loads and microbial abundance. This higher microbial load is becoming an imperceptible threat to the survival rate of sea turtle embryos on the nesting beaches. However, like other reptiles and faunal groups, turtles also secrete cloacal fluids or oviductal fluids while laying eggs which possess antimicrobial properties to various pathogenic bacteria and fungi. The cloacal fluid contains both simple glycoproteins and Antimicrobial Peptides (AMPs), which play a role in antimicrobial defense. AMPs have been isolated from other fauna where a good number of research has been carried out on protein molecular biology for their application in the pharma industry for therapeutic uses. Though sporadic and preliminary investigations have been carried out on the antimicrobial nature of cloacal fluids, no in-depth insight is available regarding their mechanism of action, the biochemical and molecular engineering of these simple glycoproteins, and their potential pharmaceutical applications. Further, the studies have been mostly restricted to a few species and few provinces only. Hence, lots of research gaps need to be addressed on this aspect of turtle conservation. The Convention on Biological Diversity envisaged International Governments to conserve biodiversity with people's participation along with the flow of benefit sharing to the conserver of bioresources. The current review was carried out to bring insight into the antimicrobial nature of cloacaloviductal fluids and their potential for chelonian conservation.
Hynobius retardatus is a salamander distributed in Hokkaido, Japan which is a subarctic region, and populations breed in both urban and coastal areas. To understand why some populations of this species can breed in coastal areas, we tested the salinity tolerance of H. retardatus eggs collected from both coastal and urban areas. At 0 ppt salinity (control), over 95% of eggs hatched normally in both coastal and urban populations. However, survival rate of eggs was significantly different among populations in 4 ppt and 5 ppt salinity. No eggs hatched over 10 ppt salinity in all populations. Deformation rate was also increased with salinity level, and differed among populations. Our results showed that eggs from coastal populations had higher survival in high salinity compared to eggs from urban populations.
Reserva Tesoro Escondido is located within the Tumbes-Choco-Magdalena biodiversity hotspot in north-west Ecuador and is home to approximately 679 amphibian species. This study aimed to investigate the effects of disturbance on amphibian species richness, abundance and assemblage through the use of visual encounter surveys along three study sites within the Reserva Tesoro Escondido. The results from these surveys report 406 observations and 46% of the total known amphibian species. Species evenness and diversity did not significantly vary across three sites sampled in the reserve even when accounting for abiotic factors, resulting in a site-specific species assemblage. Generalised Linear Models (GLM) investigated species richness and abundance relationship to environmental variables, finding altitude as the most significant factor on species abundance and richness. Overall, the results showed great diversity and no trace of species homogenisation across habitats which may be linked to disturbance.
Molecular species delimitation can clarify species limits and uncover morphologically cryptic taxa, particularly in groups that have conflicting taxonomies based on morphology alone. We reassess the phylogenetic relationships within Echis, a viperid genus widely distributed in the Eastern Hemisphere with a complicated taxonomic history. Using 134 mitochondrial cytb sequences sampled from ten of the twelve currently recognised species, we applied gene-tree and distance-based species delimitation methods to delineate evolutionary significant units within Echis. Our results validate current taxa, adding additional support to recently described species, and uncover cryptic genetic diversity within Echis. Although single-locus delimitation methods may not fully capture species diversity, congruent support between methods can identify lineages in need of future investigation. We emphasise that the lineages identified here can be used as a guide for further geographic sampling and in an genomics, morphometrics and ecological data in a unified framework.
This study represents the first application of radio telemetry on the Critically Endangered Valcheta frog Pleurodema somuncurense from Argentina's Patagonia, aimed at understanding its spatial ecology, daily movements and home range. Six adult individuals were equipped with radio transmitters to assess their activity patterns and habitat use. Average travel distances from sunset to night detection and from sunset to sunrise were 6.47 m (+/- 4.2) and 6.32 m (+/- 4.87), respectively, with no significant difference (Student's t-test, p = 0.42, alpha = 0.05). Over a complete activity cycle, individuals moved an average of 8.62 metres (SD = 2.2). The estimated home range was 39 m(2) including an individual with heightened movement, and 30 m(2) excluding it. Movements <= 5 m were categorised as local adjustments, while > 5 m were exploratory migrations, the latter comprising 25.54% of movements in most individuals, though one frog exhibited 56.25%. Despite successful data collection, high mortality and transmitter displacement highlight the technique's limitations in aquatic anurans. Findings from this study provide valuable data on P. somuncurense's habitat connectivity needs, informing restoration and conservation efforts across its restricted range. Future studies should consider adjusting the telemetry approach to mitigate the impact on behaviour and survival.
The Manapany day gecko Phelsuma inexpectata is endemic to R & eacute;union Island and listed as a Critically Endangered morphological data are scarce. Based on 389 captures across its geographic range, we provide the first large data set on body size allowing estimation of size at sexual maturity. Based on the snout-vent length (SVL) distribution of mature males and females, the transition size between the immature stage and the mature stage is estimated at a minimum of 42 mm SVL. Unambiguous indicators of sexual maturity are observed at a minimum SVL of 42 mm in males and 47 mm in females. Males are significantly larger than females, and both can reach a larger size than previously described in the literature. Finally, based on the temporal distribution of gravid females, we show that the egg production period may begin earlier than previously described in the literature.
The red-spotted tokay gecko Gekko gecko (Linnaeus, 1758) is a widely distributed Asian gecko that has established outside of its native range in southern Florida, USA. This study used genotypic and phenotypic data to determine whether multiple, distinct forms of red-spotted tokay gecko are present in southern Florida, as has previously been hypothesised. Analysis of mitochondrial (ND2) and nuclear (RAG-1) sequence data identified two discrete mito-nuclear lineages in southern Florida, and population-level morphological structure was non-randomly associated with mito-nuclear lineage, confirming a weak but significant genotypephenotype link. Multiple lines of evidence thus indicate the introduction of two distinct forms of tokay gecko to southern Florida.
Radiotelemetry has emerged as a crucial tool in wildlife biology, enabling researchers to monitor animal movements and behaviours in their natural habitats. While extensively used across various taxa, there remains a scarcity of studies dedicated to optimising radiotelemetry techniques for reptiles, especially small-medium lizard species (50-400 mm total length). In this study, the efficacy of two radio transmitters (Lotek PIP5 and Telemetrie-Service Dessau models) and different attachment methods on sand lizards inhabiting vineyard ecosystems were investigated. We evaluated three harness designs adopted over two years of fieldwork, the Adapted Rappole-Harness (ARH), Shoulder Harness (SH), and Axillary Harness (AH), considering methodological details, attachment longevity, signal range and strength, potential behavioural effects, threats to lizards' health and survival. Our results indicated that the ARH model was unsuitable, as lizards quickly removed it after few minutes. The SH remained attached for a maximum of 10 days, while the AH lasted up to 17 days, withstanding adverse environmental conditions and terrain abrasion. This study provides valuable insights into optimising radiotelemetry techniques for small-medium reptile species. By considering harness design, attachment location, materials and transmitter shape, researchers can enhance the welfare of tagged individuals and improve the efficiency of telemetry studies. Furthermore, this research underscores the need for standardised guidelines for transmitter attachment in reptiles, promoting animal welfare and advancing scientific understanding in this field. Sharing experiences and collaborating within the scientific community will foster progress in developing effective and ethical transmitter attachment protocols for small-medium reptiles.
How species interact with their environments is critical to ensuring proper conservation action. Interactions come in many forms, but one of the most basic and least studied for tropical freshwater chelonians seems to be their diet, a proxy for determining generalist versus specialist species. Even less represented in the scientific literature on chelonians are studies of intraspecific variation in diet, specifically dietary differences between the sexes and ontogenetic shifts in diet for large-bodied species. Herein, we investigate the diets of male, female and juvenile (< 25 cm SLC) Trionyx triunguis in both their east and west African range to evaluate differences and measure their dietary generalism. We found ontogenetic and location-based dietary differences.
Semi-arid environments impose significant thermal stress on ectotherms, requiring specialised water acquisition strategies. This study investigated the water status of three lizard species from the Caatinga, examining the interaction between environmental factors and physiological adaptations for water acquisition. To achieve this, we combined field data-including body mass, body condition and body temperature-with induced hydration experiments to quantify water uptake. Additionally, environmental factors such as soil and air temperature, as well as humidity, were measured. Ameivula ocellifera exhibited the highest water absorption, potentially reflecting greater dehydration due to its active foraging and sun exposure. Conversely, Tropidurus semitaeniatus absorbed less water, suggesting better hydration, possibly linked to its rocky habitat that may enhance water retention. Soil temperature and humidity significantly influenced the water status of all species, underscoring the role of ectothermy in water regulation. These findings highlight the importance of ecological context and environmental conditions in shaping water-related adaptations in semi-arid lizards.
Studying the ecological and evolutionary relations between parasites and their hosts is relevant for understanding the biology and conservation of hosts, as it helps to determine which factors influence parasitism, whether intrinsic (sex, age, morphology) or extrinsic (environmental). Glaucomastix abaetensis is an endemic lizard found in the restingas along the northern coast of the state of Bahia, in the north-eastern region of Brazil, and is classified as Endangered. The aim of the present study was to determine the parameters of the parasite ecology of populations of G. abaetensis in two areas with restinga vegetation. Of the 166 individuals studied, 25.3% harboured parasites, with an average infection intensity of 3.63 +/- 0.84 (ranging from 1 to 7.6). The results obtained for this species had not been previously documented and may contribute to conservation plans for the species and the ecosystem in which they live, as information on the parasite-host relationship is essential for understanding the interactions of this species within the environment.
Observed sex ratios of adult smooth snakes Coronella austriaca vary widely across studies, raising the question whether this species shows skewed sex ratios already at birth, and whether this depends on the condition of the mother. A total of 15 gravid females were caught and kept in captivity to give birth. We measured and weighed these females before and after parturition, as well as each of their offspring. DNA was collected from each individual. Neonate sex was identified using multiple methods, allowing us to compare the accuracy of the conventional approach (total-to-tail length ratio) and hemipenal eversion (or 'popping') with the results of molecular analysis. Based on the 107 offspring, we found that hemipenal eversion did not lead to the same sex identification as DNA analysis in 3.6% of the cases, while the conventional approach disagreed in 8.3% of the cases. Given the high level of expertise and risk involved with the eversion technique, we recommend using the conventional method to identify the sex of neonates, augmented with DNA analyses for intermediate length ratios, between 5.32 and 5.68. Females lost on average 44.0% of their weight at parturition, with heavier females giving birth to more or heavier offspring. Individual neonate weight was positively related to the weight of their mothers, but negatively with the number of siblings. While neonate sex ratios varied strongly among mothers, the overall male to female ratio in this study was 1:0.91. The skewed sex ratios observed in the field (female-biased in summer: 1:3.44, male-biased in spring and autumn: 1:0.57) are therefore most likely due to sex-specific behaviour and resulting detection probabilities changing over the seasons, and potentially by sex-specific survival rates.
