Frog Development Research Articles

Successful development of European tree frog (Hyla arborea Linnaeus, 1758) populations in the south-west and west of Luxembourg following reintroduction

In this article, we provide a comprehensive overview of our European tree frog reintroduction, from the sourcing and captive-rearing of donor animals, through reintroduction and population development, to the current status of the project. Before the start of the project, only one isolated population remained in the east of the country. Starting with two initial reintroductions (2012 to 2014), two tree frog populations have developed over the past decade and we have managed to save the species from extinction on the national level. While both populations have been expanding rapidly in recent years, they show noticeable differences regarding initial development and spread. Further reintroductions to reinforce these populations were carried out from 2019 to 2024. In total, more than 7,000 juveniles and tadpoles were released over the entire duration of the project, resulting in ca. 830 calling males at 61 sites in 2024. Our long-term annual monitoring provides detailed data on population development and spread, which are presented and discussed. In addition, comparisons with similar tree frog reintroduction projects in other countries are made and logistical and epidemiological aspects of the reintroduction project are highlighted. Finally, we give an outlook on practical implications for conservation management, upcoming challenges and future focal points of the project.

Functions and Mechanism of Thyroid Hormone Receptor Action During Amphibian Development.

Thyroid hormones and their receptors (TRs) play critical roles during vertebrate development. One of the most dramatic developmental processes regulated by thyroid hormones is frog metamorphosis, which mimics the postembryonic (perinatal) period in mammals. Here, we review some of the findings on the developmental functions of thyroid hormones and TRs as well as their associated mechanisms of action obtained from this model system. More than 2 decades ago, a dual function model was proposed for TR in anuran development. During larval development, unliganded receptors recruit corepressors to repress thyroid hormone response genes to prevent premature metamorphic changes. Subsequently, when thyroid hormone levels rise, liganded receptors recruit coactivators to activate thyroid hormone response genes, leading to metamorphic changes. Over the years, molecular and genetic approaches have provided strong support for this model and have shown that it is applicable to mammalian development as well as to understanding the diverse effects of thyroid hormones in normal physiology and diseases caused by thyroid hormone signaling dysfunction.

Immunolocalization of Aquaporin 1, 2, and 9 in Anuran Testis of the Neotropical Pointedbelly Frog Leptodactylus podicipinus.

Many anuran survival strategies involve hydric regulation, and reproduction is not different. The aquaporin (AQP) family plays an important role in water transport and regulation in many tissues, including the male gonad. The testes undergo various stages of change during the reproductive cycle, and water balance is an important factor for ensuring reproductive success. Considering the relevance of water control in testicular development in anurans and the lack of research regarding the tissue localization of AQP in the male gonad, the present study investigated the expression of three AQPs (1, 2, and 9) in the testis of the neotropical anuran species Leptodactylus podicipinus during two different periods of the reproductive cycle (reproductive and non-reproductive). AQP1 and 2 immunoreactions were found in early germ cells, spermatozoa, Leydig cells, and Sertoli cells, which were more frequently expressed within the reproductive period. AQP1 was also found in the testicular blood vessels. AQP9 was identified predominantly in the epithelium of the intratesticular ducts of reproductive-period individuals. This study presents, for the first time, the localization of AQP1, AQP2, and AQP9 in the testes of an anuran species and the differences in their location during two distinct periods of the reproductive cycle.

Comparative muscle anatomy of the anuran pelvis and hindlimb in relation to locomotor mode.

Frogs have a highly conserved body plan, yet they employ a diverse array of locomotor modes, making them ideal organisms for investigating the relationships between morphology and locomotor function, in particular whether anatomical complexity is a prerequisite for functional complexity. We use diffusible iodine contrast-enhanced microCT (diceCT) imaging to digitally dissect the gross muscle anatomy of the pelvis and hindlimbs for 30 species of frogs representing five primary locomotor modes, including the first known detailed dissection for some of the world's smallest frogs, forming the largest digital comparative analysis of musculoskeletal structure in any vertebrate clade to date. By linking musculoskeletal dissections and phylogenetic comparative methods, we then quantify and compare relationships between anatomy and function across over 160 million years of anuran evolution. In summary, we have found that bone lengths and pelvic crest sizes are generally not reliable predictors of muscle sizes, which highlights important implications for future palaeontological studies. Our investigation also presents previously unreported differences in muscle anatomy between frogs specialising in different locomotor modes, including several of the smallest frog hindlimb muscles, which are extremely difficult to extract and measure using traditional approaches. Furthermore, we find evidence of many-to-one and one-to-many mapping of form to function across the phylogeny. Additionally, we perform the first quantitative analysis of how the degree of muscle separation can differ between frogs. We find evidence that phylogenetic history is the key contributing factor to muscle separation in the pelvis and thigh, while the separation of shank muscles is influenced more strongly by locomotor mode. Finally, our anatomical 3D reconstructions are published alongside this manuscript to contribute towards future research and serve as educational materials.

Biomarkers at the Individual and Biochemical Level: Effects of Pure and Formulated Lambda-Cyhalothrin in Boana pulchella Tadpoles (Duméril and Bibron, 1841).

We compared the effects of lambda-cyhalothrin as the pure active ingredient and as a formulated product (Zero®), on the larval stage of the autochthonous species Boana pulchella. We evaluated ecotoxicological endpoints, behavioral and developmental alterations, and the biochemical detoxifying, neurotoxic, and oxidative stress responses, covering a wide concentration range from environmental to high application levels. Both pyrethroid preparations displayed similar ecotoxicity (median lethal concentration of ~0.5 mg/L), with the lethal effect of Zero® being more pronounced than that of the active ingredient. Sublethal behavioral alterations in natatory activity were observed at 1000 times lower concentrations, indicating the ecological hazard of tadpole exposure to this pyrethroid at environmentally relevant concentrations. Biochemical endpoints in B. pulchella larvae showed significant responses to lambda-cyhalothrin in the ng/L range; these responses were different for the pure or the formulated product, and they were variable at higher concentrations. Principal components analysis confirmed the prevalence of biochemical responses as early endpoints at the lowest lambda-cyhalothrin concentrations; the Integrated Biomarker Response Index proportionally increased with pyrethroid concentration in a similar way for the pure and the formulated products. We conclude that lambda-cyhalothrin is of concern from an environmental perspective, with particular emphasis on autochthonous anuran development. The battery of biochemical biomarkers included in our study showed a consistent integrated biomarker response, indicating that this is a potent tool for monitoring impacts on amphibians. Environ Toxicol Chem 2024;00:1-11. © 2024 SETAC.

Molecular basis of urostyle development in frogs: genes and gene regulation underlying an evolutionary novelty.

Evolutionary novelties entail the origin of morphologies that enable new functions. These features can arise through changes to gene function and regulation. One key novelty is the fused rod at the end of the vertebral column in anurans, the urostyle. This feature is composed of a coccyx and a hypochord, both of which ossify during metamorphosis. To elucidate the genetic basis of these features, we used laser capture microdissection of these tissues and did RNA-seq and ATAC-seq at three developmental stages in tadpoles of Xenopus tropicalis. RNA-seq reveals that the coccyx and hypochord have two different molecular signatures. Neuronal (TUBB3) and muscle markers (MYH3) are upregulated in coccygeal tissues, whereas T-box genes (TBXT, TBXT.2), corticosteroid stress hormones (CRCH.1) and matrix metallopeptidases (MMP1, MMP8 and MMP13) are upregulated in the hypochord. ATAC-seq reveals potential regulatory regions that are observed in proximity to candidate genes that regulate ossification identified from RNA-seq. Even though an ossifying hypochord is only present in anurans, this ossification between the vertebral column and the notochord resembles a congenital vertebral anomaly seen prenatally in humans caused by an ectopic expression of the TBXT/TBXT.2 gene. This work opens the way to functional studies that can elucidate anuran bauplan evolution.

Cadmium bioaccumulation dynamics during amphibian development and metamorphosis

Cadmium pollution poses a significant threat to aquatic ecosystems due to its propensity to bioaccumulate and cause toxicity. This study assessed the complex dynamics of cadmium uptake, accumulation and distribution across anuran development to provide new insights into the fate of cadmium burdens during metamorphosis and compare the susceptibility of different life stages to cadmium accumulation. Tadpoles of various developmental stages were exposed to dissolved 109-cadmium and depurated in clean water in a series of experiments. Temporal changes in whole-body and tissue concentrations were analysed using gamma spectroscopy, and anatomical distributions were visualised using autoradiography. Results showed that animals exposed at the onset of metamorphic climax (forelimb emergence) retained significantly less cadmium than animals exposed through larval stages. After exposure, cadmium partitioned predominantly in the skin, gills and remains of metamorphs, whereas larvae accumulated cadmium predominately through their gut. This shows a shift in the primary route of uptake at the onset of climax, which relates to the structural and functional changes of uptake sites through metamorphosis. During climax, some cadmium was redistributed in tissues developing de novo, such as the forelimbs, and concentrated in the regressing tail. Our findings highlight the need for stage-specific considerations in assessing exposure risks.

The chondrocranium of the tadpole of Hymenochirus boettgeri (Anura: Pipidae) and the sequence and timing of its development

The evolutionary development of the vertebrate head has played a critical role in shaping the diversity of body plans and ecological roles within vertebrate species. This evolutionary journey is characterised by the emergence of the head compartment during the Cambrian radiation, the evolution of jaws during the Silurian, and the subsequent diversification of vertebrate groups. The cranium, consisting of the neurocranium, dermatocranium, and viscerocranium, plays a central role in craniofacial support. Research on the development of the cranium has been carried out in several vertebrate species, providing valuable insights into their unique patterns of cartilage development. While most vertebrates show typical sequences of chondrocranial development, anurans divert from these patterns. Our study focused on the chondrocranial development of Congo dwarf frog Hymenochirus boettgeri (Anura: Pipidae) tadpoles, providing a detailed sequential analysis from mesenchymal elements to the premetamorphic chondrocranium. The chondrocranium of these tadpoles showed several reductions as a consequence of their miniaturization and their unique suction feeding lifestyle. We found a mosaic-like development of anuran mandibular and hyoid arches, and we also discussed the intricate patterns of suprarostral cartilage development and deviations in branchial basket development compared to other anuran species. Our study also contrasts anuran neurocranial development with that of other osteichthyan species, highlighting unique features such as the similar direction of development of anterior and posterior neurocranial components. Overall, our research contributes to our understanding of chondrocranial development in anurans, highlighting both conserved and unique features in H. boettgeri tadpoles. Our findings enrich our knowledge of vertebrate cranial development and provide insights into the evolutionary history of anuran chondrocranial features.

Evaluating potential developmental toxicity of perfluoroalkyl and polyfluoroalkyl substances in Xenopus laevis embryos and larvae.

As part of the US Environmental Protection Agency's perfluoroalkyl and polyfluoroalkyl substances (PFAS) Action Plan, the agency is committed to increasing our understanding of the potential ecological effects of PFAS. The objective of these studies was to examine the developmental toxicity of PFAS using the laboratory model amphibian species Xenopus laevis. We had two primary aims: (1) to understand the developmental toxicity of a structurally diverse set of PFAS compounds in developing embryos and (2) to characterize the potential impacts of perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorooctanoic acid (PFOA), and hexafluoropropylene oxide-dimer acid (HFPO-DA a.k.a. GenX), on growth and thyroid hormone-controlled metamorphosis. We employed a combination of static renewal and flow-through exposure designs. Embryos were exposed to 17 structurally diverse PFAS starting at the midblastula stage through the completion of organogenesis (96 h). To investigate impacts on PFOS, PFOA, PFHxS, and HFPO-DA on development and metamorphosis, larvae were exposed from premetamorphosis (Nieuwkoop Faber stage 51 or 54) through pro metamorphosis. Of the PFAS tested in embryos, only 1H,1H,10H,10H-perfluorodecane-1,10-diol (FC10-diol) and perfluorohexanesulfonamide (FHxSA) exposure resulted in clear concentration-dependent developmental toxicity. For both of these PFAS, a significant increase in mortality was observed at 2.5 and 5mg/L. For FC10-diol, 100% of the surviving embryos were malformed at 1.25 and 2.5mg/L, while for FHxSA, a significant increase in malformations (100%) was observed at 2.5 and 5mg/L. Developmental stage achieved was the most sensitive endpoint with significant effects observed at 1.25 and 0.625 mg/L for FC10-diol and FHxSA, respectively. In larval studies, we observed impacts on growth following exposure to PFHxS and PFOS at concentrations of 100 and 2.5mg/L, respectively, while no impacts were observed in larvae when exposed to PFOA and HFPO-DA at concentration of 100 mg/L. Further, we did not observe impacts on thyroid endpoints in exposed larvae. These experiments have broadened our understanding of the impact of PFAS on anuran development.

A cretaceous frog with eggs from northwestern China provides fossil evidence for sexual maturity preceding skeletal maturity in anurans.

Mesozoic fossils of frogs are rare in the palaeontological record, particularly those exhibiting soft tissues that offer limited insights into early life-history characteristics. Here we report on a skeletally immature frog from the Lower Cretaceous of northwest China, with egg masses in the body and eggs in the oviduct, indicative of a gravid female. CT reconstruction of the specimen allows referral to Gansubatrachus qilianensis and we assign it as a paratype complementing the diagnosis of the type species. The new fossil, which might represent a younger individual than the holotype of Gansubatrachus, shows that sexual maturation occurred before full adulthood in this frog and provides evidence of death linked to mating behaviour. We also discuss other potential sources of variation and life-history traits of Gansubatrachus. The new finding represents the oldest Early Cretaceous frog preserving in situ eggs and provides a glimpse into ancient anuran development during Mesozoic times.

Effects of Mixed Mineral Supplementation in On-Farm Feeds on the Metamorphosis Development and Growth Performances of Frog (Hoplobatrachus rugulosus) Tadpoles

Effects of Mixed Mineral Supplementation in On-Farm Feeds on the Metamorphosis Development and Growth Performances of Frog (Hoplobatrachus rugulosus) Tadpoles

The global importance and interplay of colour-based protective and thermoregulatory functions in frogs

Small-scale studies have shown that colour lightness variation can have important physiological implications in ectotherms, with darker species having greater heating rates, as well as protection against pathogens and photooxidative damage. Using data for 41% (3059) of all known frog and toad species (Anura) from across the world, we reveal ubiquitous and strong clines of decreasing colour lightness towards colder regions and regions with higher pathogen pressure and UVB radiation. The relative importance of pathogen resistance is higher in the tropics and that of thermoregulation is higher in temperate regions. The results suggest that these functions influence colour lightness evolution in anurans and filtered for more similarly coloured species under climatic extremes, while their concurrent importance resulted in high within-assemblage variation in productive regions. Our findings indicate three important functions of colour lightness in anurans – thermoregulation, pathogen and UVB protection – and broaden support for colour lightness-environment relationships in ectotherms.

Direct development in Atlantic Forest anurans: What can environmental and biotic influences explain about its evolution and occurrence?

Different environmental and biological factors can originate and support different alternative life histories in different taxonomic groups. Likewise, these factors are important for the processes that assemble and structure communities. Amphibians, besides being highly susceptible to environmental conditions, have various reproductive strategies, such as the direct development of individuals. Several hypotheses have been raised about possible selective pressures related to the emergence of direct development in anurans, as well as the relationship between environmental characteristics and the occurrence of these species. Such investigations, however, have mainly focused on specific clades and/or regions. Here, we use structural equation modelling to investigate the relationships between different abiotic (temperature, precipitation, humidity, and terrain slope) and biotic (phylogenetic composition and functional diversity) factors and the proportion of species with direct development in 766 anuran communities of the Atlantic Forest, a biome with a vast diversity of anuran species and high environmental complexity. Anuran communities with higher proportions of direct developing species were found to be mainly influenced by low potential evapotranspiration, low temperature seasonality, and high functional diversity. Phylogenetic composition and terrain slope were also found to be important in determining the occurrence of these species in Atlantic Forest communities. These results show the importance of these factors in the structuring of these communities and provide important contributions to the knowledge of direct development in anurans.

Effects of mifepristone, a model compound with anti-progestogenic activity, on the development of African clawed frog (Xenopus laevis)

The objective of this study was to assess the effects of a model substance with anti-progestogenic activity on development of African clawed frog (Xenopus laevis) from tadpole to juvenile stage. Mifepristone, a synthetic progesterone receptor-blocking steroid hormone used in medicine as an abortifacient, was chosen as a model compound with anti-progestogenic activity. In the experiment, African clawed frog tadpoles were exposed to mifepristone at three concentrations (2, 21, and 215 ng L−1). A control group was exposed to dimethyl sulfoxide (DMSO; 0.001 %). The experiment started when tadpoles reached stages 47–48 according to Nieuwkoop and Faber (NF; 1994) and continued until stage NF 66, when metamorphosis was complete. Exposure to mifepristone had no significant effect on the rate of tadpole development, occurrence of morphological anomalies, weight, body length, or sex ratio. Mortality was within an acceptable range of 0–3.6 % throughout the test and did not differ among the groups. Histopathological examination of the gonads and thyroid gland revealed no significant changes. Therefore, we can conclude that mifepristone had no negative effect on development of the African clawed frog up to juvenile stage. Nevertheless, at the highest tested mifepristone concentration (215 ng L−1), gene expression analysis revealed up-regulation of mRNA expression of nuclear progesterone receptor (npr), membrane progesterone receptor (mpr), estrogen receptor beta (esrβ), and luteinizing hormone (lh) in the brain–pituitary complex of exposed frogs at stage NF 66. Higher mRNA expression of npr was also found in frogs exposed to 22 ng L−1 mifepristone compared to the solvent control. These findings confirmed the anti-progestogenic activity of mifepristone in frogs because the up-regulation of progesterone receptors occurs if progesterone availability in the body is reduced. All the observed changes in combination may have negative consequences for reproduction and reproductive behavior later in life.

High relative humidity and temperature limit disease development and mortality in golden frogs of Panama, Atelopus zeteki, infected with Batrachochytrium dendrobatidis

AbstractTo combat the loss of species due to emerging infectious diseases, scientists must incorporate ecological parameters, such as temperature and humidity, to understand how the environment affects host–pathogen interactions. The fungal disease chytridiomycosis is a compelling case study to investigate the role of both temperature and humidity on infectious disease, as both the fungal pathogen (Batrachochytrium dendrobatidis, Bd) and the host (amphibians) are heavily influenced by these abiotic factors. We performed two experiments to investigate the importance of relative humidity and temperature on frog immunity (production of antimicrobial skin secretions) and disease development in captive golden frogs (Atelopus zeteki) of Panama. We found that the quantity of skin secretions significantly decreased over time in frogs moved from low to medium and high relative humidity treatments. Following Bd exposure, frogs in high temperature (26–27 °C) and high relative humidity (80–90%) had lower pathogen loads and survived significantly longer than frogs kept in all other treatment conditions, including high temperature and low relative humidity. These results suggest that high relative humidity may be an important, although less understood, mediator of Bd infection and the survival of golden frogs. Because the environment can drastically alter disease dynamics, understanding how temperature and humidity influence chytridiomycosis outcomes in golden frogs may be essential for the success of the reintroduction of captive frogs.

Ecology, sexual dimorphism, and jumping evolution in anurans.

Sexual dimorphism (SD) is a common feature of animals, and selection for sexually dimorphic traits may affect both functional morphological traits and organismal performance. Trait evolution through natural selection can also vary across environments. However, whether the evolution of organismal performance is distinct between the sexes is rarely tested in a phylogenetic comparative context. Anurans commonly exhibit sexual size dimorphism, which may affect jumping performance given the effects of body size on locomotion. They also live in a wide variety of microhabitats. Yet the relationships among dimorphism, performance, and ecology remain underexamined in anurans. Here, we explore relationships between microhabitat use, body size, and jumping performance in males and females to determine the drivers of dimorphic patterns in jumping performance. Using methods for predicting jumping performance through anatomical measurements, we describe how fecundity selection and natural selection associated with body size and microhabitat have likely shaped female jumping performance. We found that the magnitude of sexual size dimorphism (where females are about 14% larger than males) was much lower than dimorphism in muscle volume, where females had 42% more muscle than males (after accounting for body size). Despite these sometimes-large averages, phylogenetic t-tests failed to show the statistical significance of SD for any variable, indicating sexually dimorphic species tend to be closely related. While SD of jumping performance did not vary among microhabitats, we found female jumping velocity and energy differed across microhabitats. Overall, our findings indicate that differences in sex-specific reproductive roles, size, jumping-related morphology, and performance are all important determinants in how selection has led to the incredible ecophenotypic diversity of anurans.

Restricting living space: Development and larval morphology in sticky frogs (Microhylidae: Kalophrynus) with different reproductive modes

We compare reproductive features, development, and larval morphology in three closely related species of sticky frogs (Kalophrynus Tschudi, 1838) inhabiting the lowland and mountain forests of Vietnam and displaying a variety of reproductive modes. While K. interlineatus breeds in open temporary ponds, K. honbaensis and K. cryptophonus are phytotelm-breeders using tree hollows and bamboo stems for reproduction. Their tadpoles also differ in trophic specialization: larval K. interlineatus are typical suspension-feeders, whereas K. honbaensis and K. cryptophonus are obligatorily oophagous. All three species differ in egg and clutch sizes, duration of embryonal period and hatching stage, and the structure of the larval digestive tract and skeleton. Based on external and internal morphology, we conclude that tadpoles of K. interlineatus and K. cryptophonus represent two “extremes” of the adaptive spectrum of microhylid larvae, while K. honbaensis displays a set of transitory traits. Relying on these new findings in anuran biology, we discuss reproductive, ontogenetic, and morphological rearrangements during the transition from pond breeding to phytotelm breeding and from microphagy to macrophagy as well as the significance of the revealed adaptations to different habitats and larval life modes.

Multiple interacting stressors influence development, growth, and morphology of Pacific Chorus Frog (Pseudacris regilla) larvae

Freshwater ecosystems are threatened by climate change and invasive species. Amphibians are important members of freshwater communities and are susceptible to negative effects of climate change and invasion. Furthermore, both climate change and invasion can influence density of amphibian larvae at the microhabitat scale because of larval clustering. To understand the effects of climate change and invasion on Pacific Chorus Frog Pseudacris regilla (Baird and Girard, 1852) larvae, a 2 × 2 × 2 factorial experiment was carried out with a climate treatment (future/historical; simulated as changes in both temperature and hydroperiod), indirect exposure to the invasive Brook Stickleback Culaea inconstans (Kirtland, 1840) fish (chemical cues present/absent), and conspecific density (conspecific present/absent). We measured tadpole survival and development rate along with variables related to body shape, including mass, growth, growth rate, body mass index, tail fin depth, tail muscle depth, tail muscle width, and rear limb length. We assessed the effects of 3 common and important stressors (climate, invasive species, and density) alone and in combination with the other stressors to explore their interactions. Climate change, as simulated by our study, had large effects on Pacific Chorus Frog tadpole development and body shape. Brook Stickleback chemical cues had smaller but important effects on body shape and development rate when combined with additional stressors. Competition because of presence of a conspecific tadpole also reduced survival and had large effects on body shape. Pairwise interactions were largely additive or antagonistic. Three-way stressor interactions were most often antagonistic, resulting in less-than-additive effects of the 3 stressors together. However, 3 synergistic 3-way emergent interactions were detected. When all 3 stressors were present, development rate was faster than expected but rear limb length and tail muscle width were smaller than expected. Our results illustrate that climate change and conspecific density have wide-ranging effects on amphibian growth, development, and morphology—effects which may carry over into the terrestrial stage and reduce fitness. Furthermore, our findings reveal complex stressor interactions that were not predictable from single stressor effects or pairwise stressor effects, illustrating the difficulty in predicting multiple stressor interactions in freshwater systems.

01. Annual spawn clump losses in a population of the agile frog Rana dalmatina in western France

The agile frog Rana dalmatina is a common and frequently studied species in Europe including long-term studies of population change. Several have employed spawn clump counts to give estimates of annual presence of reproductive females. Spawn clumps are also subject to predation but little is known of the extent of losses but it could impact population densities significantly. The objective of the present study was to assess the extent of spawn clump losses due to predation in a population of R. dalmatina in western France using data from numbers of spawn clumps recorded over a four-year period (2019–2022). Spawn counts were greatest during 2019 but numbers declined with a zero count in 2022. Predation was greatest in 2021, the year total counts were lowest, but there were no statistical difference between annual losses, which varied from 22.9–41.6 %. Most spawn was deposited in a series of ditches rather than in the two available ponds but statistically predation levels were in agreement, with ditches ranging from 26.1–40 % versus ponds 28.6–40 %. Observed predators were ducks and alien crayfish Procambarus clarkii. The latter consumes all stages of frog development and hence likely represents the greater threat, especially since it has the capacity for population increase to very high numbers.

STAGES OF DEVELOPMENT AND METAMORPHOSIS OF TREE FROG POLYPEDATES LEUCOMYSTAX (AMPHIBIA, Rhacophoridae)

Most anurans have complex life cycles involving egg fertilization, embryo and larval development in aquatic habitats. Detailed descriptions of the ontogeny of embryonic, larval metamorphic and post metamorphic frogs are important for understanding the general patterns of development of representative taxa and, by comparisons of different patterns for resolving questions about systematic relationships. For anurans, staging tables are a condensed way of describing ontogenetic changes. Appropriate staging of the larval period, is therefore, fundamental to various life history studies of amphibians suggested that complete tables of development are necessary for accurate comparison of developmental stages in different organisms. Hence, tables of normal stages of development have been worked out for a number of species by several workers. Findings of the present study indicate that under natural environment as well as in the laboratory condition, the development and metamorphosis of Polypedates leucomystax was completed in about 60 – 61 days. This tree frog was observed to be dependent on the ephemeral pools at the breeding sites to complete their life cycle. The duration of development and metamorphosis of this tree frog seems to be similar to the other species of tree frog.