pp. 72-86

Authors: Gerardo J. Soria-Ortiz, Leticia M. Ochoa-Ochoa, Julieta A. Rosell & Ella Vázquez-Domínguez

Abstract: 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.

Keywords: amphibians, environmental filters, functional traits, landscape metrics, water pollution

pp. 59-71

Authors: Angela M. Mendoza-Henao, Juan Alejandro Guerrero-Cupacan, Khristian Venegas-Valencia & Mailyn A. Gonzalez

Abstract: 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 español está disponible en supplementary materials.

Keywords: cryptic diversity, Amazon, phylogeography, sampling biases, Neotropics

pp. 49-58

Authors: Roberta Ferreira Abecassis, Alfredo P. Santos-Jr, Lucas Vinicius Cavalcante Esteves, Advanio Inácio Siqueira-Silva, Selma Maria Almeida-Santos & Síria Ribeiro

Abstract: We studied the sexual dimorphism and reproductive cycle of Amphisbaena brasiliana, based on specimens from the municipality of Santarém, Pará 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.

Keywords: Amazon, Amphisbaenia, natural history, reproductive cycle, spermatogenesis

pp. 38-48

Authors: Vien Hong Thi Nguyen, Cuong The Pham, Truong Quang Nguyen, Chung Van Hoang & Anh Van Pham

Abstract: The Boulenger's spiny frog Quasipaa boulengeri Günther, 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).

Keywords: amphibians, Cao Bang Province, Ha Giang Province, insects, prey items, stomach contents

pp. 27-37

Authors: Pawan Shantiprakash Pareek, Monowar Alam Khalid, Christopher J. Michaels & Shailendra Singh

Abstract: 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 multi-collinear 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.

Keywords: Chambal river, freshwater, protected area, nest site selection, nesting ecology, PCA, Bayesian logistic regression

pp. 18-26

Authors: Natália Ferreira Torello-Viera, Karina Rodrigues da Silva Banci & Michel Varajão Garey

Abstract: 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 São Paulo is highly fragmented, resulting in local extinction of several species. The first record of caecilians on São 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 Previdência, a small urban park in São 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 domain. Our results show the importance of even small forest fragments for species conservation.

Keywords: Atlantic Forest, conservation, fragmentation, Gymnophiona, herpetofauna

pp. 9-17

Authors: Anh Van Pham, Truong Quang Nguyen, Cuong The Pham & Minh Duc Le

Abstract: 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.

Keywords: amphibian, gape hypothesis, niche overlap, prey types, stomach contents

pp. 1-8

Authors: Gumma Kubo & Akira Mori

Abstract: 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 individualʼs 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.

Keywords: predator-prey interaction, pursuit-deterrence, antipredator signal, visual display, Lacertidae