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Based on molecular and morphological evidence, we report the first record of Eleutherodactylus nitidus (Peters, 1870) from Mexico City, in the urban area of Panteón Xilotepec, Xochimilco. We discuss the remarkable urban adaptability of Eleutherodactylus and the need for additional sampling to determine if E. nitidus is native or introduced to Mexico City. [ABSTRACT FROM AUTHOR]

Background Occidozyga shiwandashaensis was recently discovered from Guangxi Province of China. Hylarana latouchii is a widespread species in southern China, including Hong Kong and Taiwan. Both species are expected to be found in the border areas between Vietnam and China; however, no records of these frogs have been documented from Vietnam so far. New information We record two species of amphibians for the first time from Vietnam, namely Occidozyga shiwandashaensis from Bac Giang Province and Hylarana latouchii from Hai Phong City and Quang Ninh Province in northern Vietnam. Morphologically, the Vietnamese representatives of O. shiwandashanensis resemble the type series from China. The specimens of H. latouchii from Vietnam slightly differ from the type series from China by having a larger size (SVL 48.6-51.7 mm in males, SVL 58.4 mm in the females vs. 36.0-40.0 mm in males, 42.0-53.0 mm in females). Genetic distances between the Vietnamese records and the type specimens of O. shiwandashanensis from China varied from 0 to 1.5% (16S gene). Genetic divergences between the Vietnamese records and H. latouchii from the type locality were 2.0-2.6% (16S gene). In addition, morphological data and natural history notes of the aforementioned species are provided, based on the new records from Vietnam. [ABSTRACT FROM AUTHOR]

Rensch's rule describes sexual size dimorphism (SSD) that decreases with increasing body size when females are larger than males and SSD that increases when males are larger than females. The plateau brown frog Rana kukunoris, a species endemic to the eastern Tibetan Plateau, exhibits female-biased size dimorphism. Using data on body size from 26 populations and age from 21 populations, we demonstrated that SSD did not increase with increasing mean female snout-vent length (SVL) when controlling for sex-specific age structure, failing to support the Rensch's rule. Thus, we suggest that fecundity selection (favouring large female size) balances out sexual selection (favouring large male size), which results in a similar divergence between males and females body size. In addition, sex-specific age differences explained most of the variation of SSD across populations. [ABSTRACT FROM AUTHOR]

We describe a new species of microhylid frog of the genus Synapturanus from the lower Putumayo basin in Loreto, Perú. Specimens inhabited the soils of stunted pole forests growing on peat. The new species is distinguished from other species of Synapturanus through morphology, genetics, and acoustic characteristics. This species differs from most nominal congeners by having a head flat in lateral view (vs convex in the rest of species), a characteristic only shared by S. rabus and S. salseri. The new species can be distinguished from S. rabus and S. salseri by a combination of morphological characters and by having an advertisement call with a note length of 0.05-0.06 seconds (vs 0.03 seconds in S. rabus) and a dominant frequency ranging from 1.73 to 1.81 kHz (vs 1.10-1.47 kHz in S. salseri). Principal component analyses of 12 morphological characters and three acoustic variables further support differences between the new species and its described and undescribed congeners. [ABSTRACT FROM AUTHOR]

The article reports on a new species of the genus Micryletta from the montane evergreen forest in the Bidoup-Nui Ba National Park at Lam Dong Province, southern Vietnam identified using molecular and morphological evidence. Topics include several morphological characters used to identify the species such as body size, and iris, the divergence of the species from all other congeners in the 16S rRNA gene sequences and the known species of paddy frogs or microhylids included in genus Micryletta.

The article describes a new Leptobrachella damingshanensis anuran species from central Guangxi, China based on morphological, molecular and acoustic data. Topics include the result of a phylogenetic analyses of the species using 16S rRNA gene fragment, a combination of characters in which the species differs from all known congeners, and a list of species included in the genus Leptobrachella found on the islands of Southeast Asia to the eastern Himalayas.

In this study, 68 specimens of the Levant Green Frog, Pelophylax bedriagae, were collected from agricultural fields around Yasouj and Noor-Abad cities, from August 2018 to May 2019 in southern Iran to investigate the blood cell morphology. Blood specimens were taken from the heart, or abdominal and facial veins. Smears were dried in room temperature, fixed by methanol and stained using Giemsa method. Blood cells (erythrocytes, leucocytes, and thrombocytes) were counted and measured using light microscopy under an optical micrometer. Based on the findings of this study, erythrocytes from the Noor-Abad population has significantly greater values relative to Yasouj population in all of the six metric characters (P < 0.05). RBC's in male frogs are also greater than those in females in all six studied characters (P < 0.05). All studied metric characters in lymphocytes are also different between two localities and sexes (P < 0.05). [ABSTRACT FROM AUTHOR]

Complete functional descriptions of the induction sequences of phenotypically plastic traits (perception to physiological regulation to response to outcome) should help us to clarify how plastic responses develop and operate. Ranid tadpoles express several plastic antipredator traits mediated by the stress hormone corticosterone, but how they influence outcomes remains uncertain. We investigated how predator-induced changes in the tail morphology of wood frog (Rana sylvatica) tadpoles influenced their escape performance over a sequence of time points when attacked by larval dragonflies (Anax junius). Tadpoles were raised with no predator exposure, chemical cues of dragonflies added once per day, or constant exposure to caged dragonflies crossed with no exogenous hormone added (vehicle control only), exogenous corticosterone, or metyrapone (a corticosteroid synthesis inhibitor). During predation trials, we detected no differences after four days, but after eight days, tadpoles exposed to larval dragonflies and exogenous corticosterone had developed deeper tail muscles and exhibited improved escape performance compared to controls. Treatment with metyrapone blocked the development of a deeper tail muscle and resulted in no difference in escape success. Our findings further link the predator-induced physiological stress response of ranid tadpoles to the development of an antipredator tail morphology that confers performance benefits. [ABSTRACT FROM AUTHOR]

Amphibia is a class of vertebrate. Amphibians are ectothermic, or cold-blooded, and they have smooth skin that must stay moist to prevent desiccation. They play an important role in nature both as predator and prey. Nagaland is one of the north eastern hilly states and it is very rich in biodiversity. Due to the geographical position Nagaland have huge number of amphibian fauna. Purpose of the present study is to get information of sociocultural relation of frog and Naga people and to study the diversity. Study was conducted through market survey and interview. Interview was conducted among the people of different age groups which are belonging to different tribes. Frog species were collected from the markets and Morphometric measurements were taken by using vernier caliper. Frog samples were kept as museum specimen. From the investigation all together 11 species from 4 families were recorded from the market and identified with the help of relevant literature. Cooking procedure of frog meat among the people of Nagaland varies from tribe to tribe and people to people. Most common method of consumption is boiling with bamboo shoot. Naga people have traditional believe that frogs have medicinal purposes. Different body parts of the frog consumed by different way to cure the various diseases. Frog eating is a traditional way and continued practice among the Naga society from the time of civilization to obtain the protein and frogs are easily available in the markets in both as fresh and dried. Frogs are being exploited from nature from year after year without having proper maintenance and conservation. The results of the study revealed that there is no reduction of frog population, though they are being collected in huge number. It is necessary to culture the frog species and to establish socioecological system through sustainable management and conservation of biodiversity. [ABSTRACT FROM AUTHOR]

A summary of the main features of the ilium and associated muscles is presented in Appendix B, and additional information on frog ilial musculature is summarized in Appendix C. The characters used to assess and compare the ilia were taken, or adapted, from those used by authors when describing new fossil frog taxa (e.g. [19]; [30]; [15]; [3]; [17]). The VSA was noted as being larger than 90° in the majority of anurans by [23], but in this survey close to a third (28%) of the southern African anuran ilia have a VSA of less than 90°, suggesting that this was an over-estimation, at least in the case of the southern African taxa. For the position of the DT relative to the acetabulum, the two most common categories for the majority of taxa are category 2 (posterior to the acetabulum) or category 3 (proximal portion of dorsal prominence at same level as acetabulum). [Extracted from the article]

• Breeding habitat can influence rice frog abundance and morphology. • Rice frog in farmland ditches exhibited highest abundance and lowest body condition. • Diverse waterbody types in agricultural landscapes benefit rice frog population. Amphibians are threatened by the intensification of agriculture throughout the world. Several studies have considered the morphology of animals to be an indicator of the health of a population, but differences in anuran morphology (especially body condition) in different breeding habitats in agricultural landscapes remain largely unknown. In this study, we investigated differences in the abundance and morphology of the rice frog (Fejervarya multistriata) in three waterbody types (ten farmland irrigation ditches, ten fruit forest drainage ditches, and ten lotus ponds) in agricultural landscapes in Shanghai, China. We sampled the snout–vent length, body mass, and body condition index for 206 individual rice frogs from the three types of waterbody. Our results showed that the abundance of rice frogs was higher in farmland irrigation ditches than in the other two habitats, whereas the snout–vent length, body mass, and body condition index of rice frogs were lower in farmland irrigation ditches than in the other two habitats. Our results suggest that breeding habitats in agricultural landscapes have different effects on rice frog abundance and morphology, and that constructing diverse waterbodies (other than farmland irrigation ditches) in the same agricultural landscape might benefit the condition of rice frogs. [ABSTRACT FROM AUTHOR]

A high concentration of Cuban treefrog (Osteopilus septentrionalis) tadpoles displaying morphological abnormalities was discovered in an untreated swimming pool in Bonita Springs, Florida. This find initiated a 4-year survey (2012-2015) of surrounding roadside drainage ditches that had been treated with insecticide for mosquito control. The study was extended to the populations of Ave Maria, Florida, and Everglades National Park. The core data set of 36,550 tadpoles from the swimming pool and ditches contained 25,136 abnormal tadpoles, an abnormality average of 68.8%, well above the 5% minimum definition for a hotspot. The frogs from Ave Maria and the Everglades National park were 0% abnormal. The type of tadpole abnormality differed between the suburban treated roadside drainage ditches versus the untreated swimming pool, although the same abnormalities were found in both the suburban treated and untreated water. In the untreated swimming pool, 70.1% of tadpoles displayed abnormalities such as bent tails, abnormal limbs, and disfigured or absent mouthparts. Larvae in the untreated swimming pool metamorphosed en masse despite abnormalities. The high frequency of abnormal metamorph abnormalities found were: kyphosis, scoliosis, microcephaly, and forelimb abnormalities. In the treated roadside drainage ditches, Gosner stage 16-25 tadpoles could not undergo metamorphosis and experienced mass mortality. The abnormalities found at Gosner stage 16 of the embryo were in the head and body. Tadpoles at Gosner stages 19-25 failed to develop gills, were bloated, had growth retardation, and mouthpart abnormalities. The older Gosner stage 25-41 tadpole populations in the ditches showed bloating, lumps, emaciation, and growth retardation. A brief synopsis of O. septentrionalis treefrog biology is also given, including breeding congregations, average 8 hour time to hatching, and 19 days metamorphosis. [ABSTRACT FROM AUTHOR]

Developmental instability provides a powerful monitoring tool to detect threats prior to population declines. Consequently, assessing the level of developmental instability by measuring fluctuating asymmetry (FA) of bilaterally symmetrical traits in association with environmental stress has become increasingly attractive. However, many studies failed in detecting a clear connection of FA to environmental stressors. Some of these may have suffered from large measurement error (ME) or the use of inappropriate methods. Here, we compared measurement accuracy and FA outcome from manual calliper measurements with those from non-destructive micro-3D-computed tomography (µCT) based skeletal measurements. Amphibians are assumed to be ideal models for measuring fluctuating asymmetry due to their sensitivity to environmental stress. For our study, we chose two bilateral, metric traits (femur and radio--ulna length) of the European Common Frog, Rana temporaria. Calliper measurements revealed meaningful FA estimates (i.e., FA exceeded ME) for radio-- ulna length only. In contrast, µCT-based measurements delivered meaningful FA estimates for both traits. ME was about twice as high for calliper measurements compared to µCT-based measurements, resulting in inflated levels of FA. Using callipers, we observed higher ME for femur measurements than for radio--ulna, meaning that ME strongly depended on the respective trait. When using µCT, however, we observed comparable ME between both traits. Our study revealed that analyses of developmental instability using manual measurements should be treated with caution. For smaller vertebrates we recommend skeletal measurements with µCT as a valuable alternative due to its greater reliability, thereby allowing for multi-trait analyses with equal accuracy. [ABSTRACT FROM AUTHOR]

Larval morphology offers some of the more important characters for the taxonomy of Meristogenys, and larval information of almost all species has been reported for this genus. However, some larval assignments in previous studies were not based on reliable methods and should be reexamined using modern techniques. In this study, we used molecular methods to re-examine the larval assignments for M. poecilus, whose larvae had been assigned previously based on conventional morphological methods. The analysis revealed that the larvae of this species had been misidentified as M. phaeomerus, a sympatric species. Here we correct the erroneous assignment and briefly comment about the taxonomic status of M. phaeomerus and M. orphnocnemis, based on our results. [ABSTRACT FROM AUTHOR]

Ecomorphology is the association between an organism's morphology and its ecology. Larval anuran amphibians (tadpoles) are classified into distinct ecomorphological guilds based upon morphological features and observations of their ecology. The extent to which guilds comprise distinct morphologies resulting from convergent evolution, the degree of morphological variability within each guild, and the degree of continuity in shape between guilds has not previously been examined in a phylogenetically informed statistical framework. Here, we examine tadpole ecomorphological guilds at a macroevolutionary scale by examining morphological diversity across the Australian continent. We use ecological data to classify species to guilds, and geometric morphometrics to quantify body shape in the tadpoles of 188 species, 77% of Australian frog diversity. We find that the ecomorphological guilds represented by Australian species are morphologically distinct, but there is substantial morphological variation associated with each guild, and all guilds together form a morphological continuum. However, in a phylogenetic comparative context, there is no significant difference in body shape among guilds. We also relate the morphological diversity of the Australian assemblage of tadpoles to a global sample and demonstrate that ecomorphological diversity of Australian tadpoles is limited with respect to worldwide species. Our results demonstrate that general patterns of ecomorphological variation are upheld in Australian tadpoles, but tadpole body shape is more variable and possibly generalist than generally appreciated. Ecomorphological guilds act as a proxy for studying assemblages of aquatic environments and modelling ecosystems. Here we study guilds of tadpoles sampled from all species of Australia to understand whether body shape can be an indicator of guild. We find that some guilds have distinct body shapes but all guilds together form a morphological continuum suggesting tadpole body shape is more variable than generally appreciated. [ABSTRACT FROM AUTHOR]

The Hyloscirtus larinopygion group is a clade of 16 species of large hylids that inhabit cascading Andean streams. They have brown coloration that, in most species, contrasts with bright marks. Herein morphological and genetic evidence is used to describe a new species of the group from Cordillera del Cóndor, a sub-Andean mountain chain that has phytogeographic affinities with the Guianan Tepuis. The new species is characterized by dark-brown coloration with contrasting bright orange flecks and by the presence of an enlarged and curved prepollex protruding as a spine. The new species is closely related to H. tapichalaca and an undescribed species from the southern Andes of Ecuador. The genetic distance between H. hillisi sp. n. and its closest relative, H. tapichalaca, is 2.9% (gene 16S mtDNA). Our phylogeny and a review of recently published phylogenies show that amphibians from Cordillera del Cóndor have close relationships with either Andean or Amazonian species. Amphibians do not show the Condor-Guianan Tepuis biogeographic link that has been documented in plants. [ABSTRACT FROM AUTHOR]

Most work with frogs has provided high relevance of information focusing primarily on adults, which is mainly due to the difficulty of identifying the larval stage of these organisms. Ilha Grande, the third largest island at the Brazilian coast, is one of the most important remnants of the Atlantic Rainforest Biome in Brazil. This study aimed to characterize the morphology of the tadpoles of 11 frog species that occur in oceanic face (southwards) of the Ilha Grande, Southeastern Brazil. Using these characters, we provide a key for the identification of these tadpoles. [ABSTRACT FROM AUTHOR]

Frog diets are influenced by multiple factors, including morphological constraints, habitat use, and seasonal variation in environmental conditions and food availability. This study combined stomach content analysis (SCA), stable isotope analysis (SIA), and estimates of prey availability to investigate the influence of body size and microhabitat use on seasonal variation of the trophic ecology of two sympatric hylids (Pseudis minuta and Scinax squalirostris). We evaluated two hypotheses: (1) the species with larger body and mouth sizes or broader use of microhabitats will have greater diet breadth, and (2) regardless of differences in morphological traits and microhabitat use, diet breadth of both species will be greater during the warmer of two periods. Pseudis minuta exhibited larger body size and mouth width and revealed broader use of microhabitats (mostly within and near major water bodies), whereas S. squalirostris had smaller body size and mouth gape and was found exclusively within or near phytotelmata (plant-held water bodies). SCA revealed that P. minuta had a more diverse diet than S. squalirostris. Only P. minuta showed temporal dietary differences, but these findings did not corroborate our prediction of greater diet diversity during the warmer and drier period when prey densities were higher. The two species had distinct carbon and nitrogen stable isotope ratios, indicating assimilation of different resources, except during the colder wetter season when their isotope spaces overlapped partially. We concluded that the two hylids did not use the same food resources on account of their differences in morphology and microhabitat use, and environmental seasonality did not influence their feeding strategies. [ABSTRACT FROM AUTHOR]

African pygmy toads of the genus Poyntonophrynus are some of the least known species of African toads. The genus comprises ten recognized species endemic to sub-Saharan Africa, five of which are restricted to southwestern Africa. Recent field research in Angola provided new material for three species of Poyntonophrynus, including a morphologically distinctive population from the Serra da Neve Inselberg. Based on a combination of external morphology, high-resolution computed tomography scanning, and molecular phylogenetic analysis, the Serra da Neve population is described as new species that is nested within the genus. The most striking character that differentiates the newly described species from its congeners is the lack of a tympanic middle ear, a condition common in the family Bufonidae, but so far not known for Poyntonophrynus. The description of this new species from southwestern Angola reinforces the biogeographic importance of the region and further suggests that southwestern Africa is the cradle of diversity for this genus. [ABSTRACT FROM AUTHOR]

The taxonomic status of some of New Zealand's endemic and threatened leiopelmatid frogs has been debated for decades. Clarifying this uncertainty is vital to their conservation, especially given the risk of extinction of cryptic taxa. We re-examined leiopelmatid diversity through multivariate analyses of the skeletal and external morphology of extinct and extant Leiopelma to determine morphological differentiation. Our results suggest that the morphological distinction between extinct taxa is greater than in modern extant taxa. While size ranges of postcranial elements overlapped within extant species, maxillae shape discriminated some extant taxa. We confirm the morphological distinctiveness of the extinct taxa recognized to date but identify latitudinal and altitudinal variation in postcranial element size and shape within the widespread Leiopelma markhami and L. waitomoensis, which suggest possible post-human extinction of cryptic taxa. Furthermore, the lack of morphological and osteological differentiation between L. archeyi and the insular extant L. hamiltoni and L. pakeka leads us to question the taxonomic distinctiveness of these three taxa. Future genetic research using modern and ancient DNA is recommended to enable species limits within Leiopelma to be tested in more detail to provide an evidence-based assessment for their conservation management. [ABSTRACT FROM AUTHOR]

Based on morphological and phylogenetic analyses (16S rRNA mtDNA), two new species of the genus Leptobrachella are described from southern China, namely L. yunkaiensis Wang, Li, Lyu & Wang, sp. n. from Dawuling Forest Station of Guangdong Province and L. wuhuangmontis Wang, Yang & Wang, sp. n. from Mt. Wuhuang of Guangxi Province. To date, the genus Leptobrachella contains 68 species, among which 13 species are known from China. The descriptions of the two new species further emphasize that the species diversity of the genus Leptobrachella from China is still highly underestimated and requires further investigations. [ABSTRACT FROM AUTHOR]

We herein report the first record of the Vietnam Flying Frog, Rhacophorus calcaneus Smith, 1924, which is previously known only from Dak Lak and Lam Dong provinces, from Hon Ba Nature Reserve, Khanh lloa Province, Vietnam. We further describe the larval morphology of the species for the first time, based on a tadpole collection from Hon Ba which was genetically matched with topotypic metamorphosed Rhacophorus and R. calcaneus from Dak Lak Province. Morphological characters of the tadpoles (Gosner stages 32, 36, 37 and 41) are as follows: Body and tail brown with numerous dark spots, ventral surface whitish. Body medium-sized, slightly depressed, elliptical in shape. Eyes of moderate size, located dorsolaterally. In lateral view, spiracle single, sinistral; lower and upper tail fin nearly of same size. Oral disc anteroventrally positioned, of trapezoidal shape and laterally emarginated, surrounded by papillae. Keratodont row formula (LTRF): 7(2-7)/3(l). Larvae are exotrophic, lentic: benthic; larval type after Orton (1953) is type IV. [ABSTRACT FROM AUTHOR]

The hyperossified frogBaurubatrachus priceiBáez & Peri 1989 from the Maastrichtian Serra da Galga Member of the Marília Formation is described in detail, as preparation of the type and only known specimen revealed significant features, particularly of the pectoral and pelvic girdles. This species is rediagnosed on the basis of the combination of plesiomorphic and derived character states, including two unique traits: cranial roof with round openings that might have contained the tympanic membrane completely circumscribed by ornamented dermal bone, and scapula bearing a conspicuous crest deflected ventrally to form a deep basin on its leading edge. Since its discovery it was suggested thatBaurubatrachusmight be a relative of the South American ceratophryids, a phylogenetic placement endorsed by recent analyses. In order to test this hypothesis considering all the available information, we conducted several maximum parsimony analyses under different weighting schemes and topological constraints, scoring 143 characters for 71 extant and extinct anuran taxa. Our taxonomic sampling included species with well-ossified dermatocrania as well as less ossified members of main neobatrachian clades to explore the impact of hyperossification, which frequently drives groupings based on homoplastic features. We also assessed the phylogenetic signal provided by cranial and postcranial partitions. Although we recovered a monophyletic Ceratophryidae repeatedly,Baurubatrachuswas not related with this nobleobatrachian group but associated with the calyptocephalellid australobatrachians, although with weak support. Other possible phylogenetic placements are also discussed, as well as microhabitat and habits, taking into account both anatomical and geological data. [ABSTRACT FROM PUBLISHER]

Abstract: The anuran body plan is defined by morphological features associated with saltatory locomotion, but these specializations may have functional consequences for other modes of locomotion. Several frog species use a quadrupedal walking gait as their primary mode of locomotion, characterized by limbs that move in diagonal pairs. Here, we examine how walking species may deviate from the ancestral body plan and how the kinematics of a quadrupedal gait are modified to accommodate the anuran body plan. We use a comparative analysis of limb lengths to test the hypothesis that quadrupedal anurans shift away from the standard anuran condition defined by short forelimbs and long hindlimbs. We also use three‐dimensional high‐speed videography in four anuran species (Kassina senegalensis, Melanophryniscus stelzneri, Phrynomantis bifasciatus, and Phyllomedusa hypochondrialis) to characterize footfall patterns and body posture during quadrupedal locomotion, measuring the angle and timing of joint excursions in the fore‐ and hindlimb during walking to compare kinematics between limbs of disparate lengths. Our results show frogs specialized for walking tend to have less disparity in the lengths of their fore‐ and hindlimbs compared with other anurans. We find quadrupedal walking species use a vertically retracted hindlimb posture to accommodate their relatively longer hindlimbs and minimize body pitch angle during a stride. Overall, this novel quadrupedal gait can be accommodated by changes in limb posture during locomotion and changes in the relative limb lengths of walking specialists. [ABSTRACT FROM AUTHOR]

Herein, we provide external and internal morphological data of Scinax skuki tadpoles from its type locality. The benthic tadpole of S. skuki has eyes and nostrils positioned dorsally, vent tube dextral and reaching the free margin of the ventral fin, oral disk ventral with posterior margin concave when partially closed, labial tooth row formula 2/3, and the presence of nonpigmented spurs behind the lower jaw. These characters, together with the absence of a tectum parietale, and the shapes of the pars articularis quadrati and suprarostral, are useful for species identification and may be informative for systematic purposes. [ABSTRACT FROM AUTHOR]

Prey-predator interactions have been studied extensively in terms of morphological and behavioural responses of prey to predation risk using diverse model systems. However, the underlying physiological changes associated with morphological, behavioural or life historical responses have been rarely investigated. Herein, we studied the effect of chronic predation risk on larval growth and metamorphosis of Hylarana indica and the underlying physiological changes in prey tadpoles. In the first experiment, tadpoles were exposed to a caged predator from Gosner stage 25–42 to record growth and metamorphosis. Further, whole body corticosterone (CORT) was measured to determine the physiological changes underlying morphological and life historical responses of these prey tadpoles. Surprisingly, tadpoles experiencing continuous predation risk grew and developed faster and metamorphosed at a larger size. Interestingly, these tadpoles had significantly lower CORT levels. In the second experiment, tadpoles were exposed to predation risk (PR) or PR + CORT from stage 25–42 to determine the role of CORT in mediating predator-induced responses of H. indica . Tadpoles facing continuous predation risk grew and developed faster and metamorphosed at a larger size reinforcing the results of the first experiment. However, when CORT was administered along with predation risk, tadpoles grew and developed slowly leading to delayed metamorphosis. Interestingly, growth and metamorphic traits of tadpoles exposed to PR + CORT were comparable to those of the control group indicating that exogenous CORT nullified the positive effect of predation risk. Apparently, CORT mediates predator-induced morphological responses of H. indica tadpoles by regulating their physiology. [ABSTRACT FROM AUTHOR]

Direct development has evolved independently several times in anurans and direct-developing species are characterized by large-scale developmental repatterning and a complete, or near complete, absence of most tadpole-specific structures. Earlier studies stressed the similarities among different direct-developing species, but more recent studies have indicated differences in the reduction of tadpole-specific structures among different taxa. Here, we describe egg deposition, clutch characteristics and embryonic development of the direct-developing squeaker frogs of the genus Arthroleptis, providing the first detailed description of direct development in Arthroleptidae. Embryonic development in Arthroleptis is characterized by the presence of an opercular fold that still encloses the developing forelimbs, the absence of external gills and an only moderately extended tail. A comparison with published information on other direct-developing anurans reveals broad dissimilarities in the formation of an opercular fold and very different tail morphology among different taxa. An egg tooth, often considered characteristic of direct-developing anurans, seems to be restricted to New World Terrarana. The embryonic diversity seen in direct-developing anuran taxa argues against simplistic assumptions about the evolution of direct development. [ABSTRACT FROM AUTHOR]

The European water frog ( Pelophylax esculentus) complex represents a unique and adequate model system for the study of interspecific hybridization and the mechanisms enabling interspecific hybrids to overcome the reproductive barriers. The difficulties in the study of individuals from the P. esculentus complex are associated with high polymorphism of morphological characters in parental species and interspecific hybrids, as well as with the presence of polyploid hybrid forms. From the discovery of the phenomenon of interspecific hybridization and the demonstration of successful reproduction of interspecific hybrids, researchers constantly searched for the methods necessary for the most accurate identification of parental species and various hybrid forms. This review describes biochemical, cytogenetic, and molecular methods and approaches used to identify individuals from the European water frog complex, as well as to analyze the genomes transferred with the gametes of hybrids. The advantages and disadvantages of these approaches are discussed. The presented methods can be used for studying other hybrid complexes of fish, amphibians, and reptiles. [ABSTRACT FROM AUTHOR]

The African clawed frog, Xenopus laevis, is one of the most widely used model organisms in biological research. However, the most recent anatomical description of X. laevis was produced nearly a century ago. Compared with other anurans, pipid frogs - including X. laevis - exhibit numerous unusual morphological features; thus, anatomical descriptions of more 'typical' frogs do not detail many aspects of X. laevis skeletal and soft-tissue morphology. The relatively new method of using iodine-based agents to stain soft tissues prior to high-resolution X-ray imaging has several advantages over gross dissection, such as enabling dissection of very small and fragile specimens, and preserving the three-dimensional topology of anatomical structures. Here, we use contrast-enhanced computed tomography to produce a high-resolution three-dimensional digital dissection of a post-metamorphic X. laevis to successfully visualize: skeletal and muscular anatomy; the nervous, respiratory, digestive, excretory and reproductive systems; and the major sense organs. Our digital dissection updates and supplements previous anatomical descriptions of this key model organism, and we present the three-dimensional data as interactive portable document format ( PDF) files that are easily accessible and freely available for research and educational purposes. The data presented here hold enormous potential for applications beyond descriptive purposes, particularly for biological researchers using this taxon as a model organism, comparative anatomy and biomechanical modelling. [ABSTRACT FROM AUTHOR]

Adaptations to captivity that reduce fitness are one of many reasons, which explain the low success rate of reintroductions. One way of testing this hypothesis is to compare an important behavioural response in captive and wild members of the same species. Thanatosis, is an anti-predator strategy that reduces the risk of death from predation, which is a common behavioral response in frogs. The study subjects for this investigation were captive and wild populations of Mantella aurantiaca. Thanatosis reaction was measured using the Tonic Immobility (TI) test, a method that consists of placing a frog on its back, restraining it in this position for a short period of time and then releasing it and measuring how much time was spent feigning death. To understand the pattern of reaction time, morphometric data were also collected as body condition can affect the duration of thanatosis. The significantly different TI times found in this study, one captive population with shorter responses, were principally an effect of body condition rather than being a result of rearing environment. However, this does not mean that we can always dismiss the importance of rearing environment in terms of behavioural skills expressed. [ABSTRACT FROM AUTHOR]

Background: Quantifying morphological diversity across taxa can provide valuable insight into evolutionary processes, yet its complexities can make it difficult to identify appropriate units for evaluation. One of the challenges in this field is identifying the processes that drive morphological evolution, especially when accounting for shape diversification across multiple structures. Differential levels of co-varying phenotypic diversification can conceal selective pressures on traits due to morphological integration or modular shape evolution of different structures, where morphological evolution of different modules is explained either by co-variation between them or by independent evolution, respectively. Methods: Here we used a 3D geometric morphometric approach with x-ray micro CT scan data of the skull and bones of forelimbs and hindlimbs of representative species from all 21 genera of the ancient Australo-Papuan myobatrachid frogs and analysed their shape both as a set of distinct modules and as a multi-modular integrative structure. We then tested three main questions: (i) are evolutionary patterns and the amount and direction of morphological changes similar in different structures and subfamilies?, (ii) do skulls and limbs show different levels of integration?, and (iii) is morphological diversity of skulls and limbs shaped by diet, locomotion, burrowing behavior, and ecology?. Results: Our results in both skulls and limbs support a complex evolutionary pattern typical of an adaptive radiation with an early burst of phenotypic variation followed by slower rates of morphological change. Skull shape diversity was phylogenetically conserved and correlated with diet whereas limb shape was more labile and associated with diet, locomotion, and burrowing behaviour. Morphological changes between different limb bones were highly correlated, depicting high morphological integration. In contrast, overall limb and skull shape displayed semi-independence in morphological evolution, indicating modularity. Conclusions: Our results illustrate how morphological diversification in animal clades can follow complex processes, entailing selective pressures from the environment as well as multiple trait covariance with varying degrees of independence across different structures. We suggest that accurately quantifying shape diversity across multiple structures is crucial in order to understand complex evolutionary processes. [ABSTRACT FROM AUTHOR]

Network analyses have been increasingly used in the context of comparative vertebrate morphology. The structural units of the vertebrate body are treated as discrete elements (nodes) of a network, whose interactions at their physical contacts (links) determine the phenotypic modules. Here, we use the network approach to study the organization of the locomotor system underlying the hindlimb of frogs. Nodes correspond to fibrous knots, skeletal and muscular units. Edges encode the ligamentous and monoaxial tendinous connections in addition to joints. Our main hypotheses are that: (1) the higher centrality scores (measured as betweenness) are recorded for fibrous elements belonging to the connective system, (2) the organization of the musculoskeletal network belongs to a non-trivial modular architecture and (3) the modules in the hindlimb reflect functional and/or developmental constraints. We confirm all our hypotheses except for the first one, since bones overpass the fibrous knots in terms of centrality. Functionally, there is a correlation between the proximal-to-distal succession of modules and the progressive recruitment of elements involved with the motion of joints during jumping. From a developmental perspective, there is a correspondence between the order of the betweenness scores and the ontogenetic chronology of hindlimbs in tetrapods. Modular architecture seems to be a successful organization, providing of the building blocks on which evolution forges the many different functional specializations that organisms exploit. [ABSTRACT FROM AUTHOR]

Research concerning the early development of anuran tadpoles has sparked new interest, ever since comparative studies revealed structural and temporal variations of embryonic stages within different taxonomic groups. In this paper we studied the early ontogeny of five species of the hylid genus Hypsiboas: H. curupi, H. pulchellus, H. riojanus and H. sp. from the H. pulchellus group, and H. faber from the homonymous group. We analyse the development of typical larval structures (oral disc), and of embryonic transient structures (external gills, ciliated cells, hatching glands and adhesive glands). The diversity in structural patterns is mainly related to the number and size of external gills, size of the adhesive glands, ciliation density and number of labial tooth ridges. In turn, heterochronic shifts mostly concern the time of adhesive gland division, and the regression of the hatching gland and ciliated cells. In some cases these variations appear to be related with oviposition sites and environments where embryos and larvae develop. Hypsiboas faber embryos, which develop in small nests outside water bodies, exhibit the largest hatching gland and large, densely ciliated and highly branched external gills as a possible response to low oxygen environments. The large and persistent adhesive glands of H. curupi and H. sp. gr. pulchellus might be related to the development of embryos and larvae in small streams. Within the same intrageneric group, certain embryonic traits of H. pulchellus (e.g., tooth row formula 2/3, minute external gills, low body ciliation) appear to be paedomorphic regarding ancestral ontogenies, but the ecological/functional correlation (if any) of these features is uncertain. [ABSTRACT FROM AUTHOR]

Trophic differentiation of tadpoles of four anuran species (Hoplobatrachus rugulosus, Microhyla fissipes, M. heymonsi, Polypedates megacephalus) with different oral morphologies was studied in temporary ponds in a monsoon tropical forest in southern Vietnam. All tadpole species were found to be omnivorous, including filter-feeding microhylids. Both gut contents analysis and stable isotope analysis provided enough evidence of resource partitioning among coexisting species. Gut contents analysis supported the expected partitioning of food resources by tadpoles with different oral morphologies and showed differences in the food spectra of filter-feeding and grazing species. Stable isotope analysis revealed more complex trophic niche segregation among grazers, as well as amongst filter-feeders. Tadpole species differed mainly in d13C values, indicating a dependency on carbon sources traceable to either of aquatic or terrestrial origins. Furthermore, tadpoles with generalised grazing oral morphology (P. megacephalus) can start feeding as suspension feeders and then shift to the rasping mode. Controlled diet experiment with P. megacephalus larvae showed a diet-tissue isotopic fractionation of approximately 1.9‰ and 1.2‰ for Δ13C and Δ15N, respectively. In natural habitats, the difference in d13C and d15N values between body tissues and gut contents of four tadpole species averaged 2.8‰ and 1.0‰, respectively. [ABSTRACT FROM AUTHOR]

Geographic barriers and elevational gradients have long been recognized as important in species diversification. Here, we illustrate an example where both mechanisms have shaped the genetic structure of the Neotropical rainfrog, Pristimantis ornatissimus, which has also resulted in speciation. This species was thought to be a single evolutionary lineage distributed throughout the Ecuadorian Chocó and the adjacent foothills of the Andes. Based on recent sampling of P. ornatissimus sensu lato, we provide molecular and morphological evidence that support the validity of a new species, which we name Pristimantis ecuadorensis sp. nov. The sister species are elevational replacements of each other; the distribution of Pristimantis ornatissimus sensu stricto is limited to the Ecuadorian Chocó ecoregion (< 1100 m), whereas the new species has only been found at Andean localities between 1450–1480 m. Given the results of the Multiple Matrix Regression with Randomization analysis, the genetic difference between P. ecuadorensis and P. ornatissimus is not explained by geographic distance nor environment, although environmental variables at a finer scale need to be tested. Therefore this speciation event might be the byproduct of stochastic historic extinction of connected populations or biogeographic events caused by barriers to dispersal such as rivers. Within P. ornatissimus sensu stricto, morphological patterns and genetic structure seem to be related to geographic isolation (e.g., rivers). Finally, we provide an updated phylogeny for the genus, including the new species, as well as other Ecuadorian Pristimantis. [ABSTRACT FROM AUTHOR]

Pathogen-mediated changes in host behaviour can result from hosts altering their habitat preferences. Although infection risk with pathogenic fungusBatrachochytrium dendrobatidisin amphibians is associated with environments favouring its growth, the relationship with microhabitat use has not been examined. Here, we aim to determine if microhabitats used by frogs during their nocturnal activity predictB. dendrobatidisprevalence and infection intensity. Our focal host,Eleutherodactylus coqui, is a habitat generalist that uses multiple habitats from the forest floor to the canopy. We analysed data onB. dendrobatidisoccurrence in 157 adults and 122 juveniles at El Yunque National forest in Puerto Rico. We categorized each individual’s nocturnal microhabitat as forest floor, curled palm fronds in the floor, arboreal bromeliads and foliage or tree trunks 50 cm to 2.5 m above ground. We found that frogs on the forest floor had the greatestB. dendrobatidisprevalence (73%), compared with those active in vegetation above ground (55%). Overall, the probability ofB. dendrobatidisinfection in frogs using microhabitats on the forest floor was twice as great as for those on arboreal substrates. Differences inB. dendrobatidisprevalence and intensity inE. coquimay be explained by specific abiotic conditions of microenvironments (temperature and humidity) affecting both pathogen and host, and by the age-specific ecological requirements of hosts. Adults were found to be most active in microhabitats where individuals had lower infection burdens, suggesting pathogen-modulated habitat choice. This work has important implications for the evolutionary dynamics of enzootic diseases and provides data that may inform potential mitigation strategies against a generalist amphibian pathogen. [ABSTRACT FROM AUTHOR]

The morphology of larvae stages of most amphibians are often completely different than in adults. Tadpole descriptions have historically been based on external characters like morphometrics, color pattern and oral disc structure. Other papers described anatomical details by the use of dissections. The increase in micro-CT scanning technology provides an opportunity to quantify and describe in detail internal characters like skeleton, musculature and organs. To date, no such tadpole descriptions exist for the well-studied Neotropical poison dart frog genus Ranitomeya (Anura: Dendrobatidae). Here we provide descriptions of the internal skeletal, musculature and organ structures of five Ranitomeya species and then provide morphological comparisons. Contrary to previous observations, closely related species display several morphological differences. For example, we observed considerable variation in chondrocranial characters, the extent of cranial ossifications, the appearance of some cranial muscles and the arrangement of inner organs. Further studies on the tadpole morphology of more species of Ranitomeya and other dendrobatid genera are needed to enable us to understand the complete morphological variation in this group. [ABSTRACT FROM AUTHOR]

The Polish botanist Józef Warszewicz (1812-1866) travelled extensively in Central and South America between 1844 and 1853 and, apart from plants, also collected frogs subsequently used to describe new species. Several of his locality data proved to be erroneous and especially species purportedly from western Panama were later rediscovered in South America. I revisit parts of his itinerary, the history, type locality, and morphology of Hyla molitor, supposedly from western Panama, but never encountered again, and conclude that it is conspecific either with Dendropsophus labialis or D. luddeckei, both Andean species from Colombia that are morphologically indistinguishable. Speculating that the types of H. molitor may have originated from the surroundings of Bogotá, where Warszewicz had actually been, I consider it a senior synonym with priority over D. labialis and transfer the taxon to Dendropsophus. [ABSTRACT FROM AUTHOR]

The taxonomy and systematics of Andean frogs of the genus Telmatobius have been considered complex, due mainly to the high levels of inter and intraspecific variation in morphological characters. Recently, Cuevas (2013) revalidated the species T. laevis Philippi 1902, which was originally described from two syntypes (one currently lost) collected in the late nineteenth century, based on photographs of the only preserved specimen. He also used bibliographic material showing that the original type material constituted two different taxa and that its type locality, previously not located, is Potrero Grande in the Andes Range of central Chile (33°28'S). Biogeographically, this implies a geographic distribution extension for the genus of more than 450 km on the other side of Andes, and that T. laevis inhabits within the distribution range of the phenotypically similar Alsodes montanus. Here I critically review the arguments of Cuevas (2013) and show that his main evidence for revalidating T. laevis, the location of its type locality, is based on an erroneous interpretation of the literature. Moreover, I point out several deficiencies and inconsistencies of the description and redescriptions of this taxon that were not addressed by Cuevas (2013). Reanalysing the literature and photographs of the only known specimen, and incorporating new geographic data, I suggest instead that the only known specimen of T. laevis belongs to T. marmoratus, its original designation, and came from an undetermined place within the traditional known range of the genus in Chile. However, this proposal is problematic due to the high degree of morphological variation exhibited by T. marmoratus, the uncertain taxonomic status of its Chilean populations and the unclear origin of the specimen. Therefore, I consider T. laevis as a species inquirenda until these issues are clarified or new biological material is obtained. Furthermore, I provide photographic and geographic data of frogs from Potrero Grande belonging to the genus Alsodes. [ABSTRACT FROM AUTHOR]

At least five different reproductive modes were reported in the neotropical frog genus Leptodactylus , all of them involving the building of foam nests. We analyzed the early ontogeny of five species of the L. fuscus group building terrestrial chambers where eggs are deposited, and of two species of the L. latrans group constructing a floating nest over the surface of lentic waters. The ontogenetic period described herein includes the occurrence of exclusively embryonic structures and the initial stages of development of larval features. In a likely relation to ecological aspects of oviposition and developmental mode, embryos of these two groups differ in several features. Embryos of the L. fuscus group were mainly pigmentless, were large sized with an extensive yolk provision, showed a dorsal kyphosis and lacked adhesive glands. Conversely, embryos of the L. latrans group were darkly pigmented, lacked a dorsal curvature, were comparatively smaller and less yolked, and showed adhesive glands in a peculiar type D morphogenetic pattern. Embryos of the L. latrans group had long, profusely branched, highly ciliated external gills, which were arranged ventrally. The comparative analysis of developmental sequences revealed an early emergence of hind limbs in Leptodactylus species relative to a reference leiuperine trajectory, an earlier differentiation of external gills in the species of the L. fuscus group, and an overall earlier development of mouthparts in embryos of the L. latrans group. Further analyses in a phylogenetic context are needed to evaluate the ancestral reconstructions of the development sequence and detect evolutionary relevant heterochronies in the genus. [ABSTRACT FROM AUTHOR]

Comparisons between populations that differ in resource availability and in environmental variables affecting the intensity of male–male competition allow insights into the mechanisms shaping reproductive allocation. Here, we studied inter-population variation in male investments in testis size and sperm length across four populations of the Yunnan pond frog ( Dianrana pleuraden ) along an altitudinal gradient in western China. Male body condition, relative testis size and sperm length did not increase with altitude despite an increasing male bias in the operational sex ratio (OSR) in high altitude was recorded. Our results were inconsistent with previous prediction that increasing latitude and/or altitude should lead to a declining male reproductive investment in anurans due to shortening breeding seasons and declining resource availability. We found a positive correlation between body condition and testes mass along the altitudinal gradient, which was indicative of a condition-dependent expression of testis size. By contrast, we recorded a non-significant correlation between testes mass and OSR, suggesting that male–male competition did not result in increasing levels of sperm competition. A non-significant correlation between sperm length and testis mass suggested that the intensity of sperm competition can account for the variation in sperm length. [ABSTRACT FROM AUTHOR]

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Although primarily terrestrial, cane toads ( Rhinella marina) sometimes climb near-vertical surfaces (tree-trunks, cliffs, fences) during foraging or dispersal activities. We scored climbing ability (in laboratory trials) of 288 cane toads from four regions in Australia, plus two sites on the island of Hawai'i. We found strong divergence in climbing ability associated not only with sex and relative limb length, but also population of origin. Within each population, longer-limbed individuals (and hence, males rather than females) were better climbers, although the geographical divergence in climbing ability remained significant even when sex and limb length were included in multivariate regression models. The geographical difference in climbing ability (but not morphology) disappeared when the progeny were raised in captivity under identical conditions, without climbing opportunities. Although influenced by morphology, climbing ability in wild-caught cane toads appears to be driven primarily by local environmental conditions that facilitate and/or reward arboreal activity. [ABSTRACT FROM AUTHOR]

We describe the outer morphology of Schismaderma carens larvae in greater detail than previous studies, with special attention to the histology of the unusual head fold in this taxa. The oral cavity is described for the first time. External morphology, including the oral disc (LTRF 2/3), overall shape, biometrical indices, oral cavity morphology, and the filter apparatus confirm that Schismaderma carens is a generalized filter-feeding tadpole, not very different from most toad tadpoles of the world. Internally some papillae around the choanae appear taller and fused than in common toad tadpoles, but their function is unclear. The dorsal horseshoe-shaped head fold is an integumental expansion, rich in blood vessels and surrounded by a thin epithelium consistent with it serving a respiratory function. Its role is interpreted as an additional gas exchange site allowing the utilization of alpha-mesosaprobic and polysaprobic waters. [ABSTRACT FROM AUTHOR]

The Truando toad, Rhaebo haematiticus, is a nocturnal anuran species that can be found in the leaf-litter layer of wet tropical forests along small streams or rivers. On the 30-31 August and 1-2 September 2015, we performed a survey of healthy individuals and individuals with morphological abnormalities of this species in order to estimate the density per square meter of malformed individuals. We defined 9 6×6 m leaf-litter plots, 50 m of separation between each one in an abandoned plantation at La Selva Biological Station. We found a density of 0.42 ind/m² of healthy individuals and a density of 0.03 ind/m2 of individuals with an abnormality. Of the 46 individuals sampled, 11 (23.9 %) had some kind of anomaly on its hind limbs. Due to the scarce information of certain species, like the Truando toad, it becomes a necessity to implement population monitoring and control programs. Therefore, we suggest continued monitoring of this population to estimate its size and evaluate effects of this phenomenon through the following years. [ABSTRACT FROM AUTHOR]

We evaluated the acute lethal and sublethal effects of technical-grade glyphosate (GLY) and the GLY-based commercial formulation Roundup ULTRA MAX® (RU) on two Gosner stages (Gss) 25 and 36 of the South-American Creole frog, Leptodactylus latrans. Bioassays were performed following standardized methods within a wide range of concentrations (0.0007-9.62 mg of acid equivalents per liter-a.e./L-of RU and 3-300 mg/L of GLY). The endpoints evaluated were mortality, swimming activity, growth, development, and the presence of morphologic abnormalities, especially in the mouthparts. No lethal effects were observed on larvae exposed to GLY during either Gs-25 or Gs-36. The concentrations inducing 50 % lethality in RU-exposed larvae at different exposure times and Gss ranged from 3.26 to 9.61 mg a.e./L. Swimming activity was affected by only RU. Effects on growth and development and the induction of morphologic abnormalities-like oral abnormalities and edema-were observed after exposure to either GLY or RU. Gs-25 was the most sensitive stage to both forms of the herbicide. The commercial formulation was much more toxic than the active ingredient on all the endpoints assessed. Effects on growth, development, and the induction of morphologic abnormalities observed in the range of environmental concentrations reported for agroecosystems of Argentina constitute an alert to the potential detrimental effects of the herbicide that could be affecting the fitness and survival of anurans in agroecosystems. [ABSTRACT FROM AUTHOR]

Ultrastructural changes in synaptic boutons of parallel fibers (PF) and the spines of Purkinje cell dendrites (PCD) in the frog cerebellum were stdied on exposure to high concentrations (1 mM) of glutamate (Glu) and NO-generating compounds, creating a model of stroke. Exposure to Glu led to envelopment of terminal boutons by spines, while NO-generating compounds, conversely, led to envelopment of spines by boutons. Morphological studies showed that in Glu solution, there was a dominance of synapses in which glial cells were surrounded by spines, while boutons were dominant in the presence of NO. On electrical stimulation of PF, the relative content of synapses whose boutons were enveloped by glial cells was greater than the proportion of synapses in which glial cells were enveloped by spines, by a factor of 10. These morphological changes reflect the functional state of PF and PCD synapses in response to the harmful influences of excess Glu and NO, apparent as different forms of synaptic contacts and neuron-glial structures. [ABSTRACT FROM AUTHOR]

A new species of Craugastoridae frog encountered from 1000-1700 m in elevation in the premontane forests of the Peruvian central Andes is described. The new species is similar in appearance to many other species of Pristimantis, but is easily distinguishable from these species by having bright red coloration on the groin, posterior surface of thighs, and shanks. The new species is only known for two localities 27 km apart in the Huánuco Region. [ABSTRACT FROM AUTHOR]

Patterns of sex-chromosome differentiation and gonadal development have been shown to vary among populations of Rana temporaria along a latitudinal transect in Sweden. Frogs from the northern-boreal population of Ammarnäs displayed well-differentiated X and Y haplotypes, early gonadal differentiation, and a perfect match between phenotypic and genotypic sex. In contrast, no differentiated Y haplotypes could be detected in the southern population of Tvedöra, where juveniles furthermore showed delayed gonadal differentiation. Here, we show that Dmrt1, a gene that plays a key role in sex determination and sexual development across all metazoans, displays significant sex differentiation in Tvedöra, with a Y-specific haplotype distinct from Ammarnäs. The differential segment is not only much shorter in Tvedöra than in Ammarnäs, it is also less differentiated and associates with both delayed gonadal differentiation and imperfect match between phenotypic and genotypic sex. Whereas Tvedöra juveniles with a local Y haplotype tend to ultimately develop as males, those without it may nevertheless become functional XX males, but with strongly female-biased progeny. Our findings suggest that the variance in patterns of sex determination documented in common frogs might result from a genetic polymorphism within a small genomic region that contains Dmrt1. They also substantiate the view that recurrent convergences of sex determination toward a limited set of chromosome pairs may result from the co-option of small genomic regions that harbor key genes from the sex-determination pathway. [ABSTRACT FROM AUTHOR]

The planar cell polarity (PCP) pathway regulates morphogenesis in various organs. The polarized localization is a key feature of core PCP factors for orchestrating cell polarity in an epithelial sheet. Several studies using Drosophila melanogaster have investigated the mechanism of the polarized localization. However, to what extent these mechanisms are conserved and how the polarization of core PCP factors is maintained in mature vertebrates are still open questions. Here, we addressed these questions by analyzing the dynamics of Vangl2, a member of core PCP factors, in the mouse oviduct epithelium. Multiple core PCP factors including Vangl2 were expressed in the mouse oviduct in postnatal stages. Vangl1, Vangl2 and Frizzled6 had polarized localization in the oviduct epithelium. Exogenously introduced expression of green fluorescent protein (GFP)-tagged core PCP factors by electroporation revealed that Vangl1, Vangl2 and Prickle2 are localized on the ovarian side of the cell periphery in the oviduct. To visualize the Vangl2 dynamics, we generated the R26-Vangl2-EGFP transgenic mice. In these mice, Vangl2-EGFP was ubiquitously expressed and showed polarized localization in multiple organs including the oviduct, the trachea, the lateral ventricle and the uterus. Fluorescence recovery after photobleaching (FRAP) analysis in the mature oviduct revealed that Vangl2 in the enriched subdomain of cell periphery (cellular edge) was more stable than Vangl2 in the less-enriched cellular edge. Furthermore, when a subregion of a Vangl2-enriched cellular edge was bleached, the Vangl2-enriched subregion neighboring the bleached region in the same cellular edge tended to decrease more intensities than the neighboring sub-region in the next Vangl2-enriched cellular edge. Finally, the polarization of Vangl2 was observed in nocodazole treated mouse viduct, suggesting the maintenance of Vangl2 asymmetry is independent of microtubule formation. Taken together, we revealed the characteristics of Vangl2 dynamics in the oviduct epithelium, and found that Vangl2 forms stable complex at the enriched cellular edge and forms compartments. Our data collectively suggest that the mechanism for maintenance of Vangl2 asymmetry in mature mouse oviduct is different from the microtubule dependent polarized transport model, which has been proposed for the reinforcement of the asymmetry of two core PCP proteins, Flamingo and Dishevelled, in the developing fly. [ABSTRACT FROM AUTHOR]