The Pantanal ecoregion hosts a diverse amphibian and reptile fauna due to environmental and landscape heterogeneity and remains poorly documented across many of its subregions. Here, we provided an updated inventory of the Private Natural Heritage Reserve Sesc Pantanal, a Ramsar site located in Midwestern Brazil, and another adjacent protected area. Our results are based on standardized field surveys (2010–2011) and complementary records from opportunistic encounters, community science data, and examination of museum collections (2015–2025). Amphibians and reptiles were sampled across four habitat types (forest, savanna, grassland, and wetland) using active visual and acoustic searches. We recorded 79 species (31 amphibians and 48 reptiles), identifying distinct community assembly patterns among habitats. While rarefaction indicates high sampling completeness for anurans, reptile richness remains underestimated, particularly in open habitats. Regional cluster analyses revealed assemblages significantly structured by geographic distance, grouping our study sites within a cohesive Pantanal-Humid Chaco unit, distinct from the surrounding upland zones of the Cerrado, Chiquitano Dry Forests, and Alto Paraná Atlantic Forest. Our findings demonstrate how integrating standardized surveys and community science data reduces Linnean and Wallacean shortfalls, while regional comparisons highlight the spatial and habitat drivers essential for evaluating biodiversity responses to ongoing hydrological changes.
Spontaneous cases of infection in the Neotropical frog Boana pulchella (Hylidae) by the fungus-like organism Valentines rwandae (Ichthyophonida, Dermocystida) in Uruguay are presented. The biological cycles of dermocystid parasites are still poorly understood, despite being increasingly studied as amphibian and fish pathogens. Dermocystid infection in amphibians is potentially lethal and is characterized by small, externally visible dermal nodules. We examined and dissected 141 male B. pulchella, among which 26 presented cutaneous infections (18.4%). The number of nodules varied from 1 to 100, but most frogs presented 5 or less. Analysis of their anatomical distribution showed that the preferred skin locations were the abdominal, pectoral and peri, regions, whereas infection in gular and dorsal skin was less prevalent than expected and absent from the dorsal skin of the head and limbs. A specimen bearing immature nodules was maintained in the laboratory, and healing of lesions was almost complete after 1 month. Only one case of internal infection was detected, comprising a single parasitic nodule in cardiac muscle tissue. Macroscopic features and the parasitic phase of V. rwandae in B. pulchella are similar to other dermocystid species that infect amphibians. This apparently non-lethal infection in this frog seems to be a good experimental model to asses the mechanisms of host invasion, pathogenicity, and infection costs of dermocystids.
Physalaemus is currently composed of 50 species divided into two clades, the P. signifer and P. cuvieri clades. Within the P. cuvieri clade, the P. cuvieri group currently includes nine species. Herein, we describe the tadpoles and embryos of P. erikae, one of the two P. cuvieri group species for which the tadpole has not been described. In general, P. erikae tadpoles are similar to those of most species of the genus and possess characteristics typical of the P. cuvieri group, including labial tooth row formula 2(2)/3(1), marginal papillae with ventral and ventrolateral gaps, and two pairs of infralabial papillae. Although knowledge about the chondrocranium in Physalaemus is scarce, several characteristics are shared among the six species for which such structure is described (e.g., suprarostral tripartite, basihyal absent, larval otic process absent). Embryonic morphology is also similar to that of other species in the group, with distinct features being the oral disc with the C4 morphogenetic pattern and long gill filaments.
American alligators (Alligator mississippiensis) are top trophic carnivores found throughout several southeastern United States. Nevertheless, little is known of alligators in certain areas of their range, including in the state of Alabama. To aid in our understanding of alligator populations and the various stressors that may influence their health, we seasonally blood sampled alligators from a wildlife refuge in east-central Alabama. Blood samples were then used to make blood smears for eventual enumeration of white blood cells (WBCs) and individuals were measured to obtain morphometrics. Univariate analysis revealed that neither season, which incorporated both abiotic and biotic factors), nor sex affected any WBC level. However, the ratio of heterophil levels to lymphocyte levels, an indicator of stress often used in ecological studies, was affected by season. Season and sex affected head length of alligators (HL, a length measurement) but not tail girth (TG, a volume measurement), suggesting juvenile alligators in Alabama seasonally alter their habitat preference. Multivariate analysis using principal component analysis revealed that season influenced the relationships between WBCs and morphometrics. The results detailed in this study, which is one of the first studies to investigate alligators in the state of Alabama, should provide a foundation for additional research into stress and the health of one of the largest alligator populations in Alabama.
Farmed crocodilians are commonly housed together in confined spaces where agonistic behaviors increase particularly in the breeding season, causing lesions that affect the skin quality. In mammals, sexual and aggressive behavior can be prevented through anti-GnRH vaccination. Since mammals and reptiles have the GnRH-I and GnRH-II forms, it was hypothesized that the anti-GnRH vaccine used in mammals would have the same effects in crocodiles. Thus, this study evaluated the effect of anti-GnRH vaccination on reproductive hormones levels and behavior in captive Morelet's crocodile (Crocodylus moreletii) during breeding (BS) and non-breeding (NB) seasons. Twenty-four subadult individuals (12 females, 12 males) were randomly assigned to two groups: (1) Vaccinated (n = 6 females and 6 males): anti-GnRH vaccination on Weeks 0, 4, and 12; and (2) Control (n = 6 females and 6 males): no vaccination. On Weeks 0, 4, 12, 22, 37, and 56, serum estradiol and progesterone levels were measured in females and serum testosterone in males, and the presence of anti-GnRH antibodies was determined. The frequency of sexual, agonistic, and maintenance behaviors was evaluated in both groups and seasons. Anti-GnRH vaccination did not affect estradiol and testosterone concentrations in BS or NB (P > 0.05), nor progesterone in BS (P > 0.05), but it increased progesterone levels in NB (P < 0.05). The vaccinated animals had anti-GnRH antibodies from Weeks 4 to 37. The frequency of sexual behaviors was lower in vaccinated animals in BS (P < 0.05). The frequency of agonistic and maintenance behaviors was similar in both groups in BS (P > 0.05) and lower in vaccinated animals in NB (P < 0.05). During the study, seven vaccinated animals developed a caseous lesion at the site of injection, and all animals from both groups showed progressive loss of body mass. Anti-GnRH vaccination did not decrease reproductive hormones levels, but it did diminish the frequency of sexual and agonistic behaviors. However, the lesions developed at the injection site make this vaccine unsuitable for crocodiles.
Andinobates opisthomelas (Boulenger, 1899) and Colostethus pratti (Boulenger, 1899) were both described on the basis of specimens from "Santa Ines, N. of Medellin, Republic of Colombia; altitude 3800 feet [1,160 m]." Unfortunately, as Colombia's political divisions were still taking form, this information is inadequate to ensure a clear understanding of the type locality. Over time, the taxonomy of these species advanced without identifying the precise location of the type locality. In addition, several independent evolutionary lineages closely related to A. opisthomelas have been identified and described as new species. Thus, we aim to clarify the exact geographical location of the type locality of A. opisthomelas and redescribe the species on the basis of newly collected topotypic material. Based on historical records, contemporaneous taxonomic literature, and administrative cartography, we identify the rural district (vereda) of Santa In & eacute;s, in the municipality of Valdivia, department of Antioquia, as the type locality of A. opisthomelas and C. pratti. Andinobates opisthomelas sensu stricto is readily diagnosed from all congeners on the basis of its dorsal skin texture, dorsal coloration, toe fringes, and advertisement call, and morphometric comparisons with populations across the northwestern Andes reveal significant differentiation. The correct voucher number of the lectotype of A. opisthomelas is BMNH 1947.2.15.22, not BMNH 1947.2.15.29 as reported previously.
Ranaviruses are emerging pathogens of ectothermic vertebrates that have been linked to mass mortality events globally in amphibians, reptiles, and fishes. In South America, ranavirus has been identified in multiple countries, but its distribution, host range, and epidemiology remain poorly characterized relative to other continents. Most infections have been documented in amphibians, particularly the invasive Aquarana catesbeiana, although detections have also included native species across Brazil, Chile, Argentina, Venezuela, Ecuador, Peru, and Colombia. To date, no studies have surveyed wild reptiles for ranavirus infection in South America, despite reptile mortality events linked to this virus in other regions. Here, we surveyed ranavirus in amphibians and reptiles of Colombia using quantitative polymerase chain reaction (qPCR) with genomic DNA extracted from toe and tail tips. We did not detect ranavirus in reptiles from the departments of Nari & ntilde;o (n = 30) or Atl & aacute;ntico (n = 30). We report the first detection of ranavirus in the striped robber frog (Pristimantis unistrigatus) in Nari & ntilde;o in southern Colombia, with a prevalence of 26.7% (8 of 30). Ranavirus was not present in amphibians from a lowland site in Atl & aacute;ntico on the northern Caribbean coast (n = 30). This study expands the known geographic and host range of ranavirus in Colombia and is the first to survey reptiles in South America. The lack of ranavirus detection in reptiles is notable but does not preclude the possibility of infection, as sample sizes, study sites, and temporal coverage were limited. Our findings highlight the potential role of direct-developing frogs of the genus Pristimantis as valuable sentinels for pathogen monitoring, given their high species diversity, local abundance, and wide elevational distribution. Previous surveys have demonstrated low-level but geographically broad ranavirus prevalence in other Pristimantis species across the Andes, though sampling has often been haphazard and limited by small sample sizes. Given the growing threats to amphibian and reptile species in Colombia, further research is needed to assess the full scope of ranavirus dynamics. We recommend integrating pathogen surveillance into ongoing ecological and conservation programs, especially in biodiverse regions where invasive species and anthropogenic pressures may amplify disease emergence.
In northeastern Brazil, the geckos Gymnodactylus darwinii and G. geckoides coexist in the coastal Atlantic Forest (AF), whereas G. geckoides also occurs in both inland areas of both the Caatinga (CA) and AF where G. darwinii is absent. This study investigates the trophic and spatial niches of G. geckoides in areas without G. darwinii and examines how the two species partition these niches when in sympatry. To this end, we sampled two AF sites-Dunas do Natal State Park (PEDN) and Jenipabu Environmental Protection Area (APAJ)-and one CA site-Serid & oacute; Ecological Station (ESEC)-in the state of Rio Grande do Norte. Analyses of diet composition and comparisons with prey availability revealed that in sites where only G. geckoides occurs (ESEC and APAJ), the species primarily selected and consumed termites (Isoptera). In contrast, at PEDN, where both species coexist, G. geckoides exhibited a more generalist diet, mainly selecting Hemiptera and termites, while G. darwinii predominantly consumed termites. The extent to which termites dominated the diet shaped the relationships between lizard size and prey size, with a lack of correlation between lizard size and maximum prey size in populations with greater termite consumption (G. geckoides from ESEC and G. darwinii from PEDN). In the CA site, G. geckoides occupied a generalist spatial niche, whereas in the AF sites it was confined to open habitats (restingas and beach dunes). In contrast, G. darwinii was restricted to forested habitats (tall and short forest), where it occupies soil microhabitats. Despite a moderate overlap in trophic niches when in sympatry, the two species exhibited complete spatial segregation, suggesting that spatial partitioning is the primary mechanism facilitating their coexistence.
Investigations into aspects of the life history of species such as sexual dimorphism, diet, and longevity are important for understanding the natural history of species. Here, we evaluate sexual size dimorphism and sexual and ontogenetic variation in the diet of the Odontophrynus asper in southern Brazil. We found that males are larger than females. Although there is no intersexual difference in diet, there is ontogenetic variation, with juveniles exhibiting a broader niche. Furthermore, males are longer-lived, living up to 8 years, while females live up to 6 years. Overall, eye-snout distance and femur and tibia-fibula length reflected age more accurately than body size and should be included in future studies.
New technology has greatly facilitated the ability to record and disseminate wildlife observation, both in established studies, as well as casual observations. This technology provides an opportunity to update and learn more about species distribution, and better implement conservation actions. The objectives of this study are to (1) Update the species list and confirm the native and introduced species of tortoise and freshwater turtles present in Bolivia, (2) compile information on the occurrence of the different species and consolidate it in a database called Quelonio-BOL, which will serve as the basis for subsequent studies, and (3) identify the centers of tortoise and freshwater turtle species richness in Bolivia. Information was compiled from an extensive review of bibliographic sources on reptiles, emphasizing information on tortoise and freshwater turtle records (terrestrial, aquatic and introduced) in Bolivia, including scientific articles in national and international journals, books, theses and gray literature (reports and unpublished data). Tortoise and freshwater turtle records deposited in scientific collections were included, as well as online records from the World Turtle Database (emys. geo.orst.edu), GBIF and iNaturalist. The database consists of a total of 7,039 records of tortoise and freshwater turtle species presence in Bolivia, of which 346 records are identified at the order level, one at the family level, 130 at the genus level, 6,562 at the species level, and eight at the subspecies level, 21 correspond to introduced species and 6,541 to native species. There are 142 records of tortoises and freshwater turtles in captivity without locality of origin. Sixteen native tortoise and freshwater turtle species and three exotic species have been identified, distributed in five families and nine genera, with the Podocnemididae family having the largest number of records (60.32%) followed by Testudinidae (25.80%). One area of species richness of native tortoise and freshwater turtle species was identified in Bolivia, with 12 species: located in central-northeastern Bolivia in the Amazon and Brazilian regions. Quelonio-BOL lays the foundation to improve knowledge about the diversity and distribution of turtles and tortoises in Bolivia.
Eupsophus migueli is an endangered amphibian endemic to the Valdivian temperate forests of southern Chile. This study assessed its distribution, habitat use, population size, diet, and threats in three localities of the Los Rios Region. Capture-recapture estimates revealed small population sizes (3-25 individuals) and densities between 1-60 individuals/ha. Individuals were found in a range of microhabitats with good water quality, and their diet was dominated by terrestrial invertebrates such as Tabanidae and Lumbricidae. The prevalence of chytrid fungus (Bd) reached 40%, though no external symptoms were observed. Threats included cattle trampling, riparian forest logging, and exotic plantations. Given the species' dependence on high-quality forest streams, we propose concrete conservation strategies: (i) protect and restore native riparian vegetation, (ii) exclude livestock from key reproductive habitats, (iii) prevent further expansion of exotic plantations near streams, and (iv) implement long-term pathogen monitoring. These actions should be integrated into regional land-use planning to ensure the persistence of this microendemic species. Our findings provide essential baseline data to inform targeted conservation planning and reinforce the need for urgent protection of Valdivian Forest remnants in the Chilean Coastal Range.
We describe a new species of frog of the genus Sarcohyla from the Transvolcanic Belt of M & eacute;xico based on new specimens and individuals previously referred to S. hapsa. Adult males of the new species have nuptial excrescences on the prepollex and fingers I-III and a reddish-brown dorsum, the flanks of juveniles are uniformly dark with small round cream spots, and stages 26-28 tadpoles have black spots on the tail. The new species is the sister-species of S. hapsa and contained in the S. bistincta group.
The rattleless rattlesnake Crotalus catalinensis is endemic to Catalana, a subtropical island with extremely dry and low productivity conditions. During 2009, we tracked 34 C. catalinensis by spool-line method to assess the frequency and distance of daily movements, as well as their fidelity to refuges. Our aim was to look for potential differences in daily movement patterns related to different habitat types, or seasonal variations in weather (dry versus post-rain). We found no differences in the body condition index between snakes living in different habitat types and no seasonal variation. Individuals showed high fidelity to their refuges and performed short movements from them; the frequency and distance of daily movements were unaffected by the habitat type where the snake was found. Individuals never moved from one habitat type to the other. Our results suggest that reproductive physiology and, in the long term, some seasonality are important factors affecting the daily movement patterns of C. catalinensis.
Animal coloration has evolved through a combination of neutral mechanisms and selective pressures. In reptiles, a group known for its remarkable diversity in both species richness and coloration, these evolutionary processes have produced a wide range of color patterns. These patterns vary from subtle, highly effective camouflage to the vibrant and striking hues seen in coral snakes and the multicolored chameleons of Madagascar. In this review, we synthesize current knowledge on color in non-avian reptiles, drawing from studies of both extant and extinct species, and outline future research directions in the field of color evolution. We advocate for a shift in the categorization of color patterns, moving away from classification based solely on color hues. Instead, we suggest a classification system based on the combination of colors that form specific patterns, considering different ecological and evolutionary scales. This approach aims to standardize terminology for taxonomic, ecological, and evolutionary studies.
Risk assessment and escape behavior can depend on demographic and environmental factors. We studied the interplay between size class and habitat on the escape behavior of the lizard Microlophus atacamensis in coastal Chile, where the species inhabits the rocky intertidal zone. We simulated an advancing predator by approaching focal lizards either parallel or perpendicular (i.e., from inland directly towards the coast) to the shoreline. Then, we assessed escaping lizards' flight initiation distance (FID) and escape path relative to the shoreline as well as its angle of escape relative to the predator (i.e., escape trajectory) as a function of size class. Flight initiation distance was related to the starting distance separating the lizard and predator, with longer starting distances associated with longer FIDs. Escaping lizards were more likely to direct their escape paths seaward 1) as the lizard's initial location became more distant from the shoreline, 2) when the threat approached perpendicular to the shoreline, and 3) when lizards had smaller body size. The angle of a lizard's escape relative to the simulated predator was related to its distance to the shoreline when approached and to the interaction between lizard body size and approach direction. Lizards that were approached when they were farther from the shoreline escaped at smaller escape angles. When approached perpendicular to the shoreline, large lizards tended to flee at larger escape angles and small lizards at small escape angles. Although M. atacamensis lives in and near the intertidal zone and obtains food in and near the water, proximity to the shoreline represents an additional factor to consider when assessing predation risk.
We present new data on the distribution of the lizard Stenocercus azureus in the Brazilian Pampa biome. This medium-sized tropidurid species inhabits open and montane environments. In Brazil, Stenocercus azureus is classified as Endangered under the IUCN criteria, largely due to scarcity of historical records and significant habitat changes caused by agricultural expansion and windfarm development. We report three new records of S. azureus in the municipalities of Sant'Ana do Livramento and Ros & aacute;rio do Sul, Rio Grande do Sul state, southernmost Brazil. Additionally, we provide an updated geographic distribution map of Stenocercus azureus and species distribution model to identify suitable areas for its occurrence and survival within the Pampa biome. Finally, we discuss threats to this species and implications for its conservation.
The Philosophical Voyage conducted by Alexandre Rodrigues Ferreira (1756-1815) and his team between 1783-1792 in Brazil is among the most impressive scientific expeditions of the eighteenth century. As it was a multidisciplinary naturalist expedition, Ferreira also dedicated attention to the amphibians and reptiles encountered during the trip, which were collected, illustrated, and described. These specimens, manuscripts, and illustrations were sent back to the Royal Cabinet of Ajuda, in Lisbon, to be studied and published upon the return of Ferreira. However, due to several circumstances, Ferreira never able to properly review, study, and publish on this material, which was eventually dispersed and studied and published by others. Here we review the herpetological results of Ferreira's expedition and compile all available data on the amphibians and reptiles of the Philosophical Voyage, including the original memoirs, illustrations, extant specimens, and all traces of Ferreira's collection spread among multiple natural history museums in Portugal and France. We also present a commented account of the extant herpetological specimens.
Montane ecosystems serve as natural laboratories for understanding and monitoring the current and future impacts of climate change. However, the mechanisms underlying biodiversity patterns in these environments remain poorly understood. We investigated how elevation and aquatic system influence anuran richness, abundance, and species turnover among three mountains in the semiarid Caatinga of Cear & aacute; State, Brazil. We also tested whether species' optimal elevations are related to their range-size distributions. We conducted field surveys at 27 sites during the rainy season (February-May 2019). We used linear mixed models to assess the effects of elevation and aquatic system on anuran assemblages, including mountain identity as a random factor to account for site-specific variation. To test Rapoport's rule, we applied non-parametric Kernel regression. Elevation significantly affected only species turnover, whereas the aquatic system influenced richness, abundance, and turnover. Although Rapoport's rule was not supported, species with optimal elevations at both low and high elevations exhibited narrow range sizes. Identifying the main drivers of anuran diversity and distribution in montane environments is crucial for understanding ecological patterns, processes, and the potential impacts of environmental change.
This study describes the algal coverage and commensal and parasitic epibionts in two species of freshwater turtles from the Chaco Ecoregion, Argentina, Acanthochelys pallidipectoris and Kinosternon scorpioides scorpioides. The leech family Glossiphoniidae (Haementeria and Helobdella) were the dominant animal epibionts for both species, constituting the first records of leech infestation for the species A. pallidipectoris and subspecies K. s. scorpioides (second record for the species). The tick Amblyomma argentinae was found attached to several A. pallidipectoris individuals-the second record for this host and a new geographic report for the province of Salta. Most turtles of both species presented a variable degree of algal coverage on the dorsum of the carapace. We analyzed how the type, prevalence and abundance of the epibionts found are a product of their distribution area and lifestyle, frequency of terrestrial excursions, and basking mode (documenting for the first time aerial basking for A. pallidipectoris) of the species studied herein.
The Neotropical lizard family Alopoglossidae currently comprises 32 species inhabiting the leaf litter of subtropical and tropical forests in northern South America. Recent studies based on morphological, osteological, and genetic data confirmed the monophyly of the family and revealed cryptic diversity within it. Alopoglossus angulatus exhibits a broad distribution across eastern Amazonia in Brazil, Suriname, Guyana, and French Guiana. Cytogenetic investigation is pivotal for phylogenetic research, providing insights into systematics and interspecific relationships. Despite recent advancements, a significant knowledge gap persists regarding chromosomal evolution within Gymnophthalmoidea. This study presents the first karyotype description for a species of Alopoglossidae, A. angulatus, which unexpectedly possesses the lowest diploid chromosome number reported to date among gymnophthalmoid lizards. Utilizing conventional staining and Ag-NOR, we describe the karyotype of A. angulatus (2n = 24), which consists of 12 macrochromosomes and 12 microchromosomes, with a putative XX:XY sex-determination system requiring further validation. All macrochromosomes are biarmed, and at least three pairs of microchromosomes exhibit a similar morphology. Furthermore, the NOR site coincides with a secondary constriction on chromosome pair 2, and we discuss its implications for chromosomal evolution within the group. To evaluate the potential influence of chromosomal changes on diversification, we employed a probabilistic testto inferthe ancestral diploid number for Gymnophthalmoidea. The best-fitting model indicates an ancestral diploid chromosome number of 2n = 42, implying that chromosomal fissions and fusions played a significant role in karyotype evolution. The low diploid number for A. angulatus suggests a high rate of chromosome fusions within this lineage; however, this hypothesis requires confirmation through karyotyping additional species within this poorly characterized family. These findings underscore the relevance of cytogenetic data for elucidating chromosome evolution in this clade.
