Search

Melanophryniscus fulvoguttatus is a small toad that inhabits the Cerrado, Atlantic Forest, and humid Chaco of South America. Due to its aposematic coloration and behavior, it is a species that may present chemical defenses such as alkaloids and a restricted diet similar to other species of the genus. Although it was described in the early 20th century, there is still little information on its natural history and ecology. Here, we described the diet, tested the sexual dimorphism, and calculated the fertility index of M. fulvoguttatus based on a sample of eight males and 21 females from a population within the Cerrado. Sexual dimorphism was assessed using 15 morphometric measures; diet was calculated as an index of relative importance by prey item and tested for sex differences; fertility was tested for relations between body size and the number of eggs; and we also estimated the reproductive investment. Our results demonstrate that this population's diet consisted mostly of ant species, with Pheidole radoszkowskii being the most important, followed by Crematogaster sp. and Cyphomyrmex transversus. Regarding sexual dimorphism, we observed that females were significantly larger than males, with a positive relationship between female size and the number of eggs. We did not find significant differences in the diets of males and females. Although the diet and reproductive aspects of M. fulvoguttatus are similar to those of its congeneric species, further studies are needed in order to address the relationship between the species diet and its chemical defenses. [ABSTRACT FROM AUTHOR]

We studied in this work the skin healing process in the terrestrial toad Melanophryniscus montevidensis. Wild specimens were acclimated in the laboratory, and an experimental skin wound of 1.5 mm diameter was made in the dorsum region under clove oil anesthesia, leaving the dermis exposed. Monitoring of the healing process by conventional histology was made up to 129 days. The epidermal protection of the wound was recovered after two days, and apparently, a complete recovery of dermal glandular structures was evident after 37 days. This feature includes the serous glands that play a relevant role in the defensive strategy of this species. No complications were recorded from the anesthetic procedure, not previously assessed in Melanophryniscus.

We report Melanophryniscus biancae Baldo, Pie, Firkowski, Ribeiro & Corrêa, 2015 from Araçatuba, Tijucas do Sul, Paraná, Brazil at 1,615-1,645 m altitude, the first record from the state of Paraná. On 8 January 2018 we heard individuals calling during the day in the leaves of Paepalanthus planifolius (Bong.) Körn. where eggs, tadpoles, and three adults were collected. This species was recently described from two upland marshes (1,310--1,465 m altitude) in northeastern Santa Catarina, where it was found at night breeding in water tanks of Eriocaulon ligulatum (Vell.) L.B.Sm. Included here are new data on this species' habitat, activity period, plant species used for oviposition, and the first female measurements. [ABSTRACT FROM AUTHOR]

A good understanding of species-habitat associations, or habitat use, is required to establish conservation strategies for any species. Many amphibian species are elusive and most information concerning amphibian habitat use comes from breeding sites where they are comparatively easy to find and study. Knowledge about retreat sites is extremely limited for most species and for the greater part of the year. For such species, it is especially important to factor in detection probability in habitat analyses, because otherwise distorted views about habitat preferences may result, e.g., when a species is more visible in habitat type B than in A, even though A may be preferred. The South American red-belly toad, Melanophryniscus pachyrhynus, is a range-restricted species from Southern Brazil and Uruguay that inhabits open areas with rocky outcrops and is usually seen only during explosive breeding events. Here we studied the fine-scale habitat use of the red-belly toad outside of the breeding season to identify retreat sites and test for the importance of accounting for species imperfect detection, using Bayesian occupancy models. We identified shrub density and the number of loose rocks as important predictors of occupancy, while detection probability was highest at intermediate temperatures. Considering the harsh (dry and hot) conditions of rocky outcrops, shrubs and loose rocks may both work as important refuges, besides providing food resources and protecting against predation. Rocky outcrops have been suffering changes in habitat configuration and we identify nonbreeding habitat preferences at a fine scale, which may help to promote population persistence, and highlight the importance of accounting for imperfect detection when studying secretive species. [ABSTRACT FROM AUTHOR]

Despite encompassing a relatively small geographical area, montane regions harbour disproportionately high levels of species diversity and endemism. Nonetheless, relatively little is known about the evolutionary mechanisms that ultimately lead to montane diversity. In this study, we used target capture of ultraconserved elements to investigate the phylogenetic relationships and diversification patterns of Melanophryniscus (Bufonidae) and Brachycephalus (Brachycephalidae), two frog genera that occur in sky islands of the southern Atlantic Forest of Brazil. Specifically, we tested whether diversification of montane species in these genera could be explained by a single climatic shift leading to isolation in sky islands, followed by climatic stability that maintained populations in allopatry. In both genera, the topologies inferred using concatenation and coalescent-based methods were concordant and had strong nodal support, except for a few recent splits, which nevertheless tended to be supported by more informative loci. Estimation of divergence time of a combined dataset using both genera is consistent with a concordant timing of their diversification. These results support the scenario of diversification by isolation in sky islands and suggest that allopatry attributable to climatic gradients in montane regions is an important mechanism for generating species diversity and endemism in these regions. [ABSTRACT FROM AUTHOR]

We analyzed the reproductive traits of a population of Melanophryniscus montevidensis. The reproductive events were associated to rainfalls. Males called from dawn to late night, were more abundant than females, and adopted alternative tactics to find partners (active search). Females were larger than males, and had mature oocytes and lipid reserves after spawning; they showed no association between size and fecundity. As an explosive breeder, females are prepared all year long for reproduction. Several individuals revealed high site-fidelity for breeding. Knowledge about breeding pattern could help to propose suitable and efficient in situ conservation measures for this endangered species. [ABSTRACT FROM AUTHOR]

Aposematic signals as well as body behaviours may be important anti-predator defences. Species of the genus Melanophryniscus are characterised by having toxic lipophilic alkaloids in the skin and for presenting a red ventral colouration, which can be observed when they perform the behaviour called the unken reflex. Both the reflex behaviour and the colouration pattern are described as defence mechanisms. However, there are currently no studies testing their effectiveness against predators. This study aimed to test experimentally if both ventral conspicuous colouration and the unken reflex in Melanophryniscus cambaraensis function as aposematic signals against visually oriented predators (birds). We simulated the species studied using three different clay toad models as follows: (a) in a normal position with green coloured bodies, (b) in the unken reflex position with green coloured body and extremities and (c) in the unken reflex position with a green body and red extremities. Models were distributed on a known M. cambaraensis breeding site and in the adjacent forest. More than half of the attacks on the models were from birds; however, there was no preference for any model type. Thus, just the presence of the red colour associated with the motionless unken reflex position does not seem to prevent attacks from potential predators. It is possible that the effective aposematic signal in Melanophryniscus is achieved through the unken reflex movement together with the subsequent exhibition of the warning colouration and the secretion of toxins. [ABSTRACT FROM AUTHOR]

The Yungas Redbelly Toad, Melanophryniscus rubriventris , is patchily distributed in Argentina, confined to the upland portion (1000–2000 m above sea level) of the montane forests of northern and central regions of Salta, and in central-eastern and south-eastern Jujuy. This species is known for its striking aposematic color variation across its geographic distribution, and was once treated as a complex of three subspecies based on distinctive color patterns. Here we assess the geographical genetic variation within M. rubriventris and quantify divergence in color and pattern among individuals sampled from Northwestern Argentina. We compare multi-gene phylogeography of M. rubriventris to patterns of dorsal and ventral coloration to test whether evolutionary affinities predict variation in warning color. Our results reveal two well-supported species lineages: one confined to the extreme northern portion of our sampling area, and the other extending over most of the Argentine portion of the species’ range, within which there are two populations. However, these well-supported evolutionary relationships do not mirror the marked variation in warning coloration. This discordance between DNA genealogy and warning color variation may reflect selection brought about by differences in local predation pressures, potentially coupled with effects of sexual selection and thermoregulation. [ABSTRACT FROM AUTHOR]

Melanophryniscus is a bufonid frog genus with a broad geographic distribution over southeastern South America. In recent years, several new species of Melanophryniscus have been discovered in southern Brazil showing a distinctive life-history strategy for the genus - breeding in phytotelmata - as well as a strong association with high-altitude regions. In this study, we use mitogenomic data to infer the phylogenetic relationships among diurnal, phytotelm-breeding Melanophryniscus and to determine the timing of their divergence. We obtained the mitochondrial genomes (not including the control region) for eight individuals of Melanophryniscus representing all three described species ( M. alipioi , M. milanoi , and M. xanthostomus ), as well as some recently-discovered and potentially new species. Gene order was conserved in all species and corresponded to the general order found in bufonids. Although the phylogenetic relationships among the studied species was poorly supported, dating confirmed that they diverged during the Pleistocene, suggesting that phytotelm breeding could have arisen during drier periods in the glacial/interglacial cycles due to a decrease in the availability of permanent streams or ephemeral/temporary streams or ponds in which Melanophryniscus species commonly breed. [ABSTRACT FROM AUTHOR]

Melanophryniscus montevidensis inhabits sandy dunes along the Rio de la Plata shoreline and Atlantic coast in Uruguay and southern Brazil. Here we report 2 specimens from different localities at eastern Buenos Aires province, Argentina, that were collected prior to the 1970s. Melanophryniscus montevidensis probably inhabited patchy sand dune environments in Buenos Aires. It is possible that the disappearance of natural environments (including dunes) in the Argentine Pampas resulted in the local extinction of M. montevidensis, a species sensitive to habitat fragmentation and anthropic modifications. [ABSTRACT FROM AUTHOR]

The article discusses the study that explore the involved factors in the pigment composition in the skin of Melanophryniscus rubriventris poison toad found in Argentina. Topics mentioned include the analysis of the pigments in the reddish orange color of the skin, the examination of the population variation of the aposematic species, and the findings that shows the function of carotenoids in the their skin coloration and as warning signals.

A new species of bufonid toad of the genus Melanophryniscus from northern Uruguay is described. It is included in the M. moreirae group and its external morphology is similar to Melanophryniscus sanmartini. Melanophryniscus sp. nov. is distinguished by having a light brown dorsal coloration with six darker longitudinal glandular ridges on the dorsal surface of the body and the gular region uniformly black.Se describe una nueva especie de anuro bufónido del género Melanophryniscus, procedente del norte de Uruguay. La nueva especie se incluye en el grupo M. moreirae y es similar, en cuanto a su morfología externa, con Melanophryniscus sanmartini. Melanophryniscus sp. nov. se distingue por presentar una coloración dorsal castaño clara con seis cordones glandulares longitudinales más oscuros en la superficie dorsal del cuerpo y la región gular de color negro uniforme.

Anuran jumping is a model system for linking muscle physiology to organismal performance. However, anuran species display substantial diversity in their locomotion, with some species performing powerful leaps from riverbanks or tree branches, while other species move predominantly via swimming, short hops or even diagonal-sequence gaits. Furthermore, many anurans with similar locomotion and morphology are actually convergent (e.g. multiple independent evolutions of 'tree frogs'), while closely related species may differ drastically, as with the walking toad (Melanophryniscus stelzneri) and bullfrog-like river toad (Phrynoides aspera) compared with other Bufonid toads. These multiple independent evolutionary changes in locomotion allowus to test the hypothesis that evolutionary increases in locomotor performance will be linked to the evolution of faster, high-power muscles. I tested the jumping, swimming and walking (when applicable) performance of 14 species of anurans and one salamander, followed by measurement of the contractile properties of the semimembranosus and plantaris longus muscles and anatomical measurements, using phylogenetic comparative methods. I found that increased jumping performance correlated to muscle contractile properties associated with muscle speed (e.g. time to peak tetanus, maximum shortening speed, peak isotonic power), and was tightly linked to relevant anatomical traits (e.g. leg length, muscle mass). Swimming performancewas not correlated to jumping, and was correlated with fewer anatomical and muscular variables. Thus, muscle properties evolve along with changes in anatomy to produce differences in overall locomotor performance. [ABSTRACT FROM AUTHOR]

The Brazilian Atlantic Forest (BAF) is recognized as one of the world’s biodiversity hotspots, with even more species per unit of area than the Amazon, however the mechanisms that led to such astonishing diversity are yet to be fully understood. In this study, we investigate the diversification of two co-distributed frog genera associated with montane areas of southern BAF: Melanophryniscus (Bufonidae) and Brachycephalus (Brachycephalidae). Species delimitation methods using mitochondrial and nuclear loci supported the existence of a remarkable number of highly endemic species in each genus, most of which occupy only one or a few adjacent mountaintops. Their timing of diversification was highly congruent, supporting recent speciation events within the past 600 thousand years. Extended Bayesian skyline plots indicate that most populations have remained relatively stable in size across the evolutionary past, with recent growth after 0.15 My, suggesting that the drastic changes found in previous studies on lowland frog species were not shared by these montane taxa. These results are consistent with the existence of a montane refugium in southern BAF, allowing species persistence through the climatic shifts experienced along the BAF during the Quaternary. [ABSTRACT FROM AUTHOR]

Three new species of Melanophryniscus are described from the Serra do Mar mountain range of the state of Santa Catarina, southern Brazil. All species are found at intermediate to high altitudes and share phytotelm-breeding as their reproductive strategy. The new species are distinguished from other phytotelm-breeding Melanophryniscus based on different combinations of the following traits: snout-vent length, presence of white and/or yellow spots on forearms, mouth, belly and cloaca, pattern and arrangement of warts, and presence and number of corneous spines. The discovery of these species in a rather restricted geographical area suggests that the diversity of phytotelm-breeding species of Melanophryniscus might be severely underestimated. The conservation status of these species is of particular concern, given that one of them is at risk of extinction not only due to its restricted habitat, but also because of anthropogenic disturbances. [ABSTRACT FROM AUTHOR]

Amphibians detect quality signals when selecting reproduction sites. We hypothesize thatMelanophryniscus rubriventris, an explosive breeding toad that reproduces in small, ephemeral water bodies, is able to select sites without predators. We performed a field experiment simulating oviposition sites, two with predators (tadpoles and bugs) and one control. Contrary to our expectations, we obtained no differences in the number of eggs deposited. We also performed an experiment to test the capability ofM. rubriventristadpoles to detect potential predators. Tadpoles could not detect predators, as other species did.Melanophryniscus rubriventrisis selecting spawning sites following other signals, not predation risk. Identifying selection cues is crucial to protect species that depend on threatened habitats. [ABSTRACT FROM AUTHOR]

Se analizó la histología tegumentaria de la región cefálica en seis especies del género Melanophryniscus, pertenecientes a los grupos stelzneri (4) y tumifrons (2), con el objetivo de esclarecer la estructura de la tumefacción frontal y su posible función. Las características generales de la histología del grupo stelzneri, coincidieron con las descripciones tegumentarias existentes para el género. Sin embargo, la región cefálica frontal en las dos especies del grupo tumifrons muestran cambios histológicos correlacionados a la tumefacción frontal. Esta estructura presenta una organización similar a otras macroglándulas presentes en la dermis de anuros (e.g., parotoides, paracnémicas), y por tanto se propone el nombre de macroglándula frontal para la misma. Los resultados obtenidos sugieren un rol defensivo para esta macroglándulaWe analyzed the histology of skin from the head region of six species of Melanophryniscus, belonging to the stelzneri (4) and tumifrons (2) groups, to understand the frontal tumefaction structure and function. The histological features of the skin in the stelzneri group are in agreement with the current description for the genus Melanophryniscus. However, the features of the skin on the anterior head region of M. tumifrons shows several changes associated with the frontal tumefaction. This structure consists of a macrogland of similar organization to that of other dermic glands (e.g., parotoid, paracnemid) of amphibians. We propose the name frontal macrogland for this structure. Our results suggest a possible defense role for this macrogland

Toads of the genus Melanophryniscus contain toxic alkaloids sequestered from a diet of mainly ants and mites. Wild-caught specimens of M. klappenbachi were fed an alkaloid-free diet and their alkaloid profile was analyzed during 38 months in captivity. Individual alkaloid patterns varied considerably. Over time, the concentration of two alkaloids, pumiliotoxin 251D and 3,5-disubstituted indolizidine 195B , significantly declined, suggesting that the toads depend on continuous access to alkaloid-containing prey to maintain natural levels of their chemical defense. [ABSTRACT FROM AUTHOR]

We communicate the finding of a subcutaneous neoplasia in a female specimen of the toad Melanophryniscus montevidensis (Bufonidae) from Uruguay. The lesion extended from the cephalic to the abdominal region, and both gross and microscopic features were typical of lipomas. This is to our knowledge the fourth case reported in amphibians. [ABSTRACT FROM AUTHOR]

Introduction: Amphibians secrete a wide diversity of chemicals from skin glands as defense against predators, parasites, and pathogens. Most defensive chemicals are produced endogenously through biosynthesis, but poison frogs sequester lipophilic alkaloids from dietary arthropods. Alkaloid composition varies greatly, even among conspecific individuals collected at the same time and place, with some individuals having only a few micrograms of one or a few alkaloids and others possessing >1 mg of >30 alkaloids. The paucity of alkaloids in juveniles and their abundance in adults suggests that alkaloids accumulate over time; however, alkaloid diversity is highly variable among adult poison frogs and has never been studied in relation to individual age. Using skeletochronology to infer individual ages and gas chromatography--mass spectrometry and vapor phase Fourier-transform infrared spectral analysis to identify the defensive chemicals of 63 individuals, we tested the relationship between defensive chemicals and age, size, and sex in the Brazilian red-belly toad, Melanophryniscus moreirae, a poison frog that possesses both sequestered alkaloids and the biosynthesized indolealkylamine bufotenine. Results: Adult females were, on average, older and larger than adult males. Juveniles were smaller but not necessarily younger than adults and possessed bufotenine and 18 of the 37 alkaloids found in adults. Alkaloid richness was positively related to age, but not size, whereas the quantities of sequestered alkaloids and bufotenine were positively related to size, but not age. Defensive chemicals were unrelated to sex, independent of size. Conclusions: The relationship between alkaloid richness and age appears to result from the gradual accumulation of alkaloids over a frog's lifetime, whereas the relationship between the quantity of defensive chemicals and size appears to be due to the greater storage capacity of larger individuals. The decoupling of age and size effects increases the amount of individual variation that can occur within a population, thereby possibly enhancing anti-predator efficacy. Further, given that both richness and quantity contribute to the overall chemical defense of individual frogs, our results suggest that older, larger individuals are better defended than younger, smaller ones. These considerations underscore the importance of including age in studies of the causes and consequences of variation in poison frog chemical defenses. [ABSTRACT FROM AUTHOR]

Bufonid poison frogs of the genus Melanophryniscus contain alkaloid-based chemical defenses that are derived from a diet of alkaloid-containing arthropods. In addition to dietary alkaloids, bufadienolide-like compounds and indolealkylamines have been identified in certain species of Melanophryniscus. Our study reports, for the first time, the co-occurrence of large quantities of both alkaloids sequestered from the diet and an endogenously biosynthesized indolalkylamine in skin secretions from individual specimens of Melanophryniscus moreirae from Brazil. GC/MS analysis of 55 individuals of M. moreirae revealed 37 dietary alkaloids and the biosynthesized indolealkylamine bufotenine. On average, pumiliotoxin 267C, bufotenine, and allopumilitoxin 323B collectively represent ca. 90 % of the defensive chemicals present in an individual. The quantity of defensive chemicals differed between sexes, with males possessing significantly less dietary alkaloid and bufotenine than females. Most of the dietary alkaloids have structures with branched-chains, indicating they are likely derived from oribatid mites. The ratio of bufotenine:alkaloid quantity decreased with increasing quantities of dietary alkaloids, suggesting that M. moreirae might regulate bufotenine synthesis in relation to sequestration of dietary alkaloids. [ABSTRACT FROM AUTHOR]

The article discusses a study concerning captive reproduction in the red bellied toad Melanophryniscus klappenbachi. Topics include the brumation period for all specimens of the kind of toads prior to breeding, reproductive behaviour in the specimens, and the metamorphosis of the specimen within 19 days of development.

Melanophryniscus moreirae is recorded from a fifth locality. A specimen was collected in Serra do Papagaio, municipality of Alagoa, Minas Gerais, Brazil, 18 km southeast from the nearest previous record in Aiuruoca. This new record fills a gap of about 32 km in the distribution of the species, between Itamonte and Aiuruoca. [ABSTRACT FROM AUTHOR]

The goal of this study was to evaluate the relative influence of terrestrial habits, season, and host body size on the species richness and abundance of helminth parasites in the toad Melanophryniscus klappenbachi, for which a greater abundance of nematode parasites was expected. A total of 90 toads were collected in the Chaco Province, Argentina. The helminth community found in infected toads included 17 taxa and was dominated particularly by larval parasites. Contrary to our expectations, nematode species showed lower values of infection parameters. Infected toads harbored a maximum of seven species, and the mean helminth richness was 3.16 ± 1.66 species per infected toads. Season played a significant effect on determining the species richness and abundance of the parasite infracommunity. Similarly, the prevalence of infection of several helminth species (8/47 %) varied greatly over time. Host body size was the main factor in determining the infrapopulation structure of helminth parasites. Species richness was significantly and negatively correlated with host body size. Strong associations were observed mainly between larvae of some species. The transmission strategies of parasites suggest that this bufonid acquires infections through direct contact with larval parasites from aquatic and terrestrial habitats and by ingestion of infective larvae. The characteristic of the host tegument, such as the presence of alkaloids, could significantly contribute to the low occurrence of infection by skin-penetrating nematodes. Results also showed that diets and mobility of the host and the local microhabitat conditions play an important role in parasitic infections of toads. [ABSTRACT FROM AUTHOR]

We present a comprehensive review of larval morphology in the Neotropical toad genus Melanophryniscus. The taxa studied included 23 species with representatives of recognized phenetic groups and different larval ecomorphological guilds: pond, stream, and phytotelm-dwelling tadpoles. Their external morphology variation is congruent with current phenetic arrangement based on adult features, but also reflects the habitat where larvae develop. Lotic tadpoles (i.e. M. tumifrons group and M. krauczuki) in general exhibit a more depressed body, a longer tail with lower fins, and larger oral discs than lentic forms (i.e. M. stelzneri group, M. moreirae, M. sanmartini, and M. langonei). Despite their peculiar, confined microhabitat, phytotelm larvae do not diverge markedly from non-arboreal species. The distinctive features of all species are the presence of a pineal end organ and the placement of the intestinal reversal point at the left of the abdomen in typical larval stages. The buccal cavity and musculoskeletal anatomy are quite conserved between species, yet some characteristics differ from those of other bufonids. The presence of one pair of subhyoid muscles is apparently an exclusive trait of Melanophryniscus among Bufonidae. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112, 417-441. [ABSTRACT FROM AUTHOR]

The article discusses red-bellied frog Melanophryniscus klappenbachi which is distributed in northern Argentina, and mentions their rapid larval development. Topics discussed include their habitat conditions, dehydration in larvae, and morphological characters. It mentions hatching and developmental rate of this larvae.

We used species distribution modeling to investigate the potential effects of climate change on 24 species of Neotropical anurans of the genus Melanophryniscus. These toads are small, have limited mobility, and a high percentage are endangered or present restricted geographical distributions. We looked at the changes in the size of suitable climatic regions and in the numbers of known occurrence sites within the distribution limits of all species. We used the MaxEnt algorithm to project current and future suitable climatic areas (a consensus of IPCC scenarios A2a and B2a for 2020 and 2080) for each species. 40% of the species may lose over 50% of their potential distribution area by 2080, whereas 28% of species may lose less than 10%. Four species had over 40% of the currently known occurrence sites outside the predicted 2080 areas. The effect of climate change (decrease in climatic suitable areas) did not differ according to the present distribution area, major habitat type or phylogenetic group of the studied species. We used the estimated decrease in specific suitable climatic range to set a conservation priority rank for Melanophryniscus species. Four species were set to high conservation priority: M. montevidensis, (100% of its original suitable range and all known occurrence points potentially lost by 2080), M. sp.2, M. cambaraensis, and M. tumifrons. Three species (M. spectabilis, M. stelzneri, and M. sp.3) were set between high to intermediate priority (more than 60% decrease in area predicted by 2080); nine species were ranked as intermediate priority, while eight species were ranked as low conservation priority. We suggest that monitoring and conservation actions should be focused primarily on those species and populations that are likely to lose the largest area of suitable climate and the largest number of known populations in the short-term. [ABSTRACT FROM AUTHOR]

We describe the external morphology, buccal cavity, chondrocranium, hyobranchial skeleton, and musculature of the tadpole of Rhinella achavali (Achaval's Toad), along with its karyotype. Tadpoles were found in a small, permanent stream and were showing schooling behavior. The characterization of the proposed species groups within Rhinella cannot be currently improved using external larval morphology, as it seems to be much conserved within this genus. Buccal cavity morphology confirms the distinctiveness of the Rhinella veraguensis (Veragua Toad) group with respect to other known Rhinella.Musculoskeletal character states are similar among bufonids, although within this family the basal genus Melanophryniscus shows some distinctive states. The karyotype is composed of 22 bi-armed chromosomes, with secondary constrictions in pair 7, as found in the other species in the Rhinella marina (Marine Toad) group. [ABSTRACT FROM AUTHOR]

The redbelly toad Melanophryniscus pachyrhynus (Miranda-Ribeiro, 1920) is a poorly known toad belonging to the M. tumifrons group, which inhabits rocky open areas on top of hilly landscapes of the Uruguayan Savanna ecoregion in Uruguay and southern Brazil. In this study we describe the advertisement and release calls from a redbelly toad population from the central Rio Grande do Sul, southern Brazil, based on recordings obtained during the winter season of 2011. The advertisement call consists of a complex call with two segments, the first segment comprising a series of single, unpulsed notes, and the second comprising a multi-pulsed note (a trill) highly variable in duration. The mean dominant frequency of the call is 2668 ± 154 Hz (2261-2932 Hz) and mean call duration is 37.07 ± 23.97 s (6.64-75.20 s). This feature, however, is highly variable depending on the duration of the second segment, which may be notably longer compared to calls of other species of the genus Melanophryniscus. The release call was recorded during amplexus of up to four individuals. It consists of a short trill with a dominant frequency of approximately 2245 Hz, emitted as a series of five to six pulsed notes, each comprising five or six pulses. The advertisement call of Melanophryniscus pachyrhynus is compared with those of four other Melanophryniscus species, and the similarities in habitat requirements and in the temporal pattern of reproduction for species of the M. tumifrons group are discussed. [ABSTRACT FROM AUTHOR]

Anurans can be classified as explosive or prolonged breeders. In species with short breeding periods, intensive competition for females is expected. We analyse the temporal breeding pattern ofMelanophryniscusaff.montevidensis, a bufonid inhabiting grasslands of Argentina, whose breeding is concentrated in events of short duration. Males are active during more than one breeding event per season, whereas most females take part in a single event per season. Active males outnumbered females by up to 14 times at one event, operational sex ratio (OSR) ranged from 0.07 to 0.75 and intensity of sexual selection (Is) from 0.69 to 24. We found a negative association betweenIsand OSR, but no correlation between number of active males per event and OSR orIs. The OSR is the key that regulates the intensity of sexual selection, nevertheless, and in spite of being explosive breeders, females would potentially have chances to select their mate. [ABSTRACT FROM PUBLISHER]

The article presents a study which described the diet of Melanophryniscus devincenzii based on the analysis of stomach contents of several specimens from the Parque Municipal de Sertão, south Brazil. It also discusses the items belonging to the prey categories, including the Acari, ants and beetles and compares the diet of female and male species.

Herein we review what is known about the chemical ecology of poison frogs with a focus on dendrobatid poison frogs. While five anuran families are known to have an alkaloid-derived chemical defense, the dendrobatids have been studied in greatest detail and provides chemical ecologists with a complex model system for understanding how chemical defenses operate in real time and may have evolved through evolutionary time. We describe the diversity of alkaloid defenses known from frogs, alkaloid sequestration, biosynthesis and modification, and we review what is known concerning arthropod sources for alkaloids. There is variation in nearly every attribute of the system and we try to describe some of the challenges associated with unraveling the complexities of this model system. [ABSTRACT FROM AUTHOR]

We present a cytogenetic survey of the basal bufonid genus Melanophryniscus that covered 14 of the 25 species currently recognized, representing the three phenetic species groups: M. moreirae, M. stelzneri, and M. tumifrons. All species presented a diploid chromosome complement constituted by 11 bi-armed chromosome pairs (2n = 2x = 22; FN = 44). Some remarkable differences were observed between species groups: chromosome pair 4 was metacentric in species of the M. tumifrons group (also with a distinctive C-positive block) but submetacentric in the M. stelzneri group and M. sanmartini (M. moreirae group); pair 5 was submetacentric in M. sanmartini and metacentric in the rest. Chromosome secondary constrictions and silver-stained nucleolar organizer regions were located either in pair 5, 7, or 8 in the M. tumifrons group, M. sanmartini and M. krauczuki (M. stelzneri group), and M. stelzneri group, respectively; and pair 7 was relatively larger in M. sanmartini and M. krauczuki. Studied cytogenetic characters support the M. tumifrons group and suggest a close relationship between M. krauczuki and M. sanmartini. These results call for a reassessment of species relations within Melanophryniscus under an inclusive phylogenetic study. [ABSTRACT FROM AUTHOR]

The aposematic toad genus Melanophryniscus is a polymorphic group with noticeable variation in colour and pattern. Here, we objectively evaluate variation in spectral reflectance and quantify variation in patterning within and among populations of the species M. rubriventris in NW Argentina. We conducted spectrophotometric analysis on 69 individuals and recorded dorsal and ventral pattern morphs of 727 individuals from six populations. We found high divergence in the reflectance spectra, the extent of brightly coloured areas, and the skin alkaloid profiles with no correlation among coloration varieties, alkaloid profiles, and the geographic distance between populations. Our analyses imply subdivision of sampled populations groupings based mostly on different dorsal colorations. Our results also reveal that populations with very similar patterns may differ markedly in colour and vice versa. It is striking that these aposematic toads show a pronounced variation in colour and patterning among and within populations showing individuals with a conspicuous bright dorsal colouration but also morphs with a rather cryptic black or drab colouration. However, the known presence of several alkaloids classes in all populations suggests that all morphs might be equally unpalatable. [ABSTRACT FROM AUTHOR]

We present here the first records of Melanophryniscus spectabilis out of its type locality and evidences of a restricted distribution for this species. We also discuss its conservation status. [ABSTRACT FROM AUTHOR]

The bufonid genus Melanophryniscus includes 26 species that are divided into three phenetic groups based on adult morphology. Larvae develop in environments such as temporary ponds, streams or phytotelms. We studied variation in external morphology related to lentic and lotic microhabitats, through landmark-based geometric morphometrics on body shape, and multivariate analysis on oral disc measurements. Results show a morphological continuum between species that inhabit lentic versus lotic water systems. Features both in body shape and oral disc coincide with previous characterizations of lentic and lotic tadpoles published elsewhere. El genero de bufonidos Melanophryniscus comprende 26 especies actualmente reunidas en tres grupos feneticos distinguidos por la morfologia de los adultos. En adicion, las larvas se desarrollan alternativamente en variados ambientes, tales como charcos, arroyos temporarios y fitotelmata. Estudiamos la variacion morfologica externa asociada a ambientes loticos y lenticos, mediante morfometria geometrica de landmarks sobre la forma del cuerpo, y analisis multivariado de las medidas del disco oral. Los resultados muestran un continuo morfologico entre las especies que habitan sistemas lenticos vs. loticos. Las caracteristicas corporales y del disco oral coinciden con caracterizaciones previas de renacuajos lenticos y loticos ya publicadas. [ABSTRACT FROM AUTHOR]

The article presents a study which analyzed the breeding habitat and natural history notes of the toad Melanophryniscus pachyrhynus in southern Brazil. It claims that the toad specie belongs to the M. tumifrons group, which are mainly present in South American countries, Brazil, Argentina and Uruguay. It cites that the calling behaviour of the M. pachyrhynus is similar to that of the male M. devincenzii and male M. orejasmirandai. It states that the M. pachyrhynus exhibited diurnal and nocturnal calling activity.

Few studies have investigated the level of individual variation in diet composition of poisonous frogs and toads. We compare the diet composition of three populations of a poisonous toad, Melanophryniscus rubriventris, and predicted that toads within a population might be constrained to forage on particular types of alkaloid-containing prey and consequently diets among populations might not diverge from each other. Most important prey categories in the diets of the three populations consisted of the same ground-dwelling arthropods. We found evidence for individuals consuming different arrays of prey types in all populations implying that this 'generalist' species is actually comprised of individuals eating different sets of the available range of prey. Formicidae, Acari, and Coleoptera were all important alkaloid-containing prey items in the diets of all populations and individuals, although there were differences in their order of importance among populations and individuals use different sets of the entire range of alkaloid-containing preys. Future research should evaluate individual diet variation in other poisonous anurans taxa given that shifts in diet composition might have important implications for understanding the consequences of alternate foraging strategies in the evolution of defensive strategies among species. [ABSTRACT FROM AUTHOR]