Two new species of the Brachycephalus pernix group (Anura: Brachycephalidae) from the state of Paraná, southern Brazil

Expression patterns of melanin-related genes are linked to crypsis and conspicuousness in a pumpkin toadlet

Colour signals play pivotal roles in different communication systems, and the evolution of these characters has been associated with behavioural ecology, integumentary production processes and perceptual mechanisms of the species involved. Here, we present the first insight into the molecular and histological basis of skin colour polymorphism within a miniaturized species of pumpkin toadlet, potentially representing the lowest size threshold for colour polytypism in tetrapods. Brachycephalus actaeus exhibits a coloration ranging from cryptic green to conspicuous orange skin, and our findings suggest that colour morphs differ in their capability to be detected by potential predators. We also found that the distribution and abundance of chromatophores are variable in the different colour morphs. The expression pattern of coloration related genes was predominantly associated with melanin synthesis (including dct, edn1, mlana, oca2, pmel, slc24a5, tyrp1 and wnt9a). Up-regulation of melanin genes in grey, green and brown skin was associated with higher melanophore abundance than in orange skin, where xanthophores predominate. Our findings provide a significant foundation for comparing and understanding the diverse pathways that contribute to the evolution of pigment production in the skin of amphibians.

An estimate of the area of occupancy and population size of Brachycephalus tridactylus (Anura: Brachycephalidae) to reassess its conservation status, with a proposal for conservation measures

Background

We are experiencing a global crisis in conservation, which has led to the prioritization of targets, such as nations, regions, and animal groups, which are necessary while resources are disputed. Brazil is a priority not only because of its megadiversity, high rates of endemism, and frequent descriptions of new species but also because of its high levels of deforestation. Among the species groups prioritized for conservation is the anurans (Amphibia: Anura), the population of which is severely declining. One group of anurans is the genus Brachycephalus, which includes 37 endemic species in the Brazilian Atlantic Rainforest. Some of these species have highly restricted distributions (<100 ha). Thirty new species have been described since 2000, and 55.3% of all species are threatened with extinction. Brachycephalus tridactylus was only recently described and remains restricted to its type locality. Because of its reduced geographical distribution (0.41 km²), it has been proposed to be considered as Vulnerable. The objective of this study is to reevaluate the conservation status of Brachycephalus tridactylus and propose conservation measures.

Methods

We searched for new populations during 2016–2020, evaluated in loco impacts and potential impacts on the species’ population, and performed an analysis of the density of this population and estimated its size. International Union for Conservation of Nature (IUCN) criteria were used to assess the conservation status of the species.

Results

We recorded the species in seven new localities (from 715–1,140 m above sea level) in the state of São Paulo up to 33 km from the type locality of the species (in state of Paraná). We estimated the area of occupancy as 148.44 km², densities as one calling male per 4.05 m² and 130.00 m², and a total population size of 4,429,722 adult individuals. Based on our finding, we proposed three lines of management: (1) formation of fire brigades, (2) management of residents’ mules in the conservation unit and surrounding areas, and (3) management of degraded areas. We recommend changing the species’ conservation status from Vulnerable to Endangered because of its fragmented distribution and decline in the area of occupancy and in the quality of its habitat. Our results have expanded the species previous geographic distribution and delimited areas without previous records. Our estimates of population density and size are in accordance with those verified for congeners. The conservation of this species benefits the environments and other species that inhabit them, being, therefore, strategic for receiving conservation actions that will spread throughout the ecosystem.

Rampant tooth loss across 200 million years of frog evolution

Teeth are present in most clades of vertebrates but have been lost completely several times in actinopterygian fishes and amniotes. Using phenotypic data collected from over 500 genera via micro-computed tomography, we provide the first rigorous assessment of the evolutionary history of dentition across all major lineages of amphibians. We demonstrate that dentition is invariably present in caecilians and salamanders, but teeth have been lost completely more than 20 times in frogs, a much higher occurrence of edentulism than in any other vertebrate group. The repeated loss of teeth in anurans is associated with a specialized diet of small invertebrate prey as well as shortening of the lower jaw, but it is not correlated with a reduction in body size. Frogs provide an unparalleled opportunity for investigating the molecular and developmental mechanisms of convergent tooth loss on a large phylogenetic scale.

Hidden by the name: A new fluorescent pumpkin toadlet from the Brachycephalus ephippium group (Anura: Brachycephalidae)

Species of Brachycephalus has been having taxonomical issues due its morphological similarity and genetic conservatism. Herein, we describe a new species of Brachycephalus from the south Mantiqueira mountain range and semidecidual forests in the municipalities of Mogi das Cruzes, Campinas and Jundiaí, state of São Paulo, Brazil, based on an integrative approach. It can be distinguished from all species of the B. ephippium species group based on morphological characters (especially osteology and head shape), advertisement call and divergence in partial mitochondrial DNA gene sequences (16S). The new species is genetically similar to B. margaritatus and morphologically similar to B. ephippium. It can be differentiated from B. ephippium by the presence of dark faded spots on skull and post-cranial plates, presence of black connective tissue connective tissue scattered over dorsal musculature, parotic plate morphology, smaller snout-vent length (adult SVL: males 13.46-15.92 mm; females 16.04-17.69 mm) and 3% genetic distance. We also present natural history data and discuss the robustness of the integrative approach, geographic distribution, genetic data, behaviour, fluorescence in ontogeny, and conservation status.

A review of the diagnosis and geographical distribution of the recently described flea toad Brachycephalus sulfuratus in relation to B. hermogenesi (Anura: Brachycephalidae)

Background

The flea toad Brachycephalus sulfuratus was recently described from southeastern and southern Brazil. In its description, the authors overlooked previous records of flea toads that had been identified as “Brachycephalus sp. nov.” and B. hermogenesi occurring in the same regions, which could suggest the possibility of up to three flea toads coexisting in southern Brazil. In addition, B. sulfuratus is characterized by substantial phenotypic variability, to an extent that compromises its current diagnosis with respect to its congener B. hermogenesi. Therefore, the current state-of-affairs regarding the geographical distribution of these two species and the identification of previously known populations is hitherto uncertain. Our goals are to reassess previous records of flea toads attributable to B. hermogenesi, B. sulfuratus and “Brachycephalus sp. nov.”, considering the description of B. sulfuratus, and to review the diagnosis of B. sulfuratus.

Methods

A critical analysis of the species identity of flea toad specimens attributable to B. hermogenesi, B. sulfuratus, or to a potentially undescribed species from southeastern and southern Brazil was based either on the analysis of morphology or on their advertisement calls. These analyses include our independent examinations of specimens and, when not possible, examinations of published descriptions. To allow for a consistent comparison of advertisement calls between B. hermogenesi and B. sulfuratus, we made recordings of both species, including in the type locality of the former.

Results

We found that morphological and call characters originally proposed as diagnostic for B. sulfuratus in relation to B. hermogenesi vary intraspecifically. Live individuals with ventral yellow spots correspond to B. sulfuratus; individuals without yellow spots can be either B. sulfuratus or B. hermogenesi. In preservative, they are indistinguishable. Previous records of Brachycephalus sp. nov. correspond to B. sulfuratus. We propose that the reduced number of notes per call and the presence of only isolated notes in the call of B. sulfuratus, as opposed to a high number of notes per call with isolated notes and note groups in the call of B. hermogenesi, as the only diagnostic characters between them. Regarding their distributions and based in our assessment, only B. sulfuratus occurs in southern Brazil, without any overlap with B. hermogenesi. There is a narrow gap between the distributions of these species around the southeast of the city of São Paulo. Our revision also revealed that some records previously attributed to B. hermogenesi in Rio de Janeiro and north São Paulo represent a distinct, unidentified flea toad that is not B. sulfuratus. Both species occur side by side in Corcovado, São Paulo, a locality from where five paratypes of B. hermogenesi were obtained. Biogeographic events that might have led to vicariance between B. hermogenesi and B. sulfuratus are discussed.

Synchrotron microtomography applied to the volumetric analysis of internal structures of Thoropa miliaris tadpoles

Amphibians are models for studying applied ecological issues such as habitat loss, pollution, disease, and global climate change due to their sensitivity and vulnerability to changes in the environment. Developmental series of amphibians are informative about their biology, and X-ray based 3D reconstruction holds promise for quantifying morphological changes during growth—some with a direct impact on the possibility of an experimental investigation on several of the ecological topics listed above. However, 3D resolution and discrimination of their soft tissues have been difficult with traditional X-ray computed tomography, without time-consuming contrast staining. Tomographic data were initially performed (pre-processing and reconstruction) using the open-source software tool SYRMEP Tomo Project. Data processing and analysis of the reconstructed tomography volumes were conducted using the segmentation semi-automatic settings of the software Avizo Fire 8, which provide information about each investigated tissues, organs or bone elements. Hence, volumetric analyses were carried out to quantify the development of structures in different tadpole developmental stages. Our work shows that synchrotron X-ray microtomography using phase-contrast mode resolves the edges of the internal tissues (as well as overall tadpole morphology), facilitating the segmentation of the investigated tissues. Reconstruction algorithms and segmentation software played an important role in the qualitative and quantitative analysis of each target structure of the Thoropa miliaris tadpole at different stages of development, providing information on volume, shape and length. The use of the synchrotron X-ray microtomography setup of the SYRMEP beamline of Elettra Synchrotron, in phase-contrast mode, allows access to volumetric data for bone formation, eye development, nervous system and notochordal changes during the development (ontogeny) of tadpoles of a cycloramphid frog Thoropa miliaris. As key elements in the normal development of these and any other frog tadpole, the application of such a comparative ontogenetic study, may hold interest to researchers in experimental and environmental disciplines.

Conservation Status of Brachycephalus Toadlets (Anura: Brachycephalidae) from the Brazilian Atlantic Rainforest

The number of described anurans has increased continuously, with many newly described species determined to be at risk. Most of these new species inhabit hotspots and are under threat of habitat loss, such as Brachycephalus, a genus of small toadlets that inhabits the litter of the Brazilian Atlantic Rainforest. Of 36 known species, 22 were described in the last decade, but only 11 have been assessed according to the IUCN Red List categories, with just one currently listed as Critically Endangered. All available data on occurrence, distribution, density, and threats to Brachycephalus were reviewed. The species extent of occurrence was estimated using the Minimum Convex Polygon method for species with three or more records and by delimiting continuous areas within the altitudinal range of species with up to two records. These data were integrated to assess the conservation status according to the IUCN criteria. Six species have been evaluated as Critically Endangered, five as Endangered, 10 as Vulnerable, five as Least Concern, and 10 as Data Deficient. Deforestation was the most common threat to imperiled Brachycephalus species. The official recognition of these categories might be more readily adopted if the microendemic nature of their geographical distribution is taken into account.

A new species of Brachycephalus (Anura: Brachycephalidae) from southern Brazil

A new miniaturized frog of the genus Brachycephalus (Anura: Brachycephalidae) is described from Morro Santo Anjo in the municipality of Massaranduba, Santa Catarina, southern Brazil. Specimens were collected from the leaf litter between 470 and 540 above sea level. The new species is distinguished from all its congeners by the combination of the following characters: (1) body robust and bufoniform; (2) size snout-vent length 9.9–11.7 mm for males and 10.0–12.9 mm for females; (3) smooth dorsum; (4) general color (in life) orange with white dots and stripe in the middle of the head and along its vertebral column; (5) iris completely black; (6) advertisement call composed of note groups; (7) isolated notes with 1–3 pulses; and (8) short isolated notes (0.002–0.027 s). An estimate of the male density of the new species is also presented. Phylogenetic information indicates that the new species is part of the southernmost clade of Brachycephalus, which includes Brachycephalus fuscolineatus, B. albolineatus, and B. boticario. The severe anthropogenic impacts in and around the type locality indicate that immediate actions should be taken to ensure the long-term preservation of the new species.

JP, Rocha CFD. Anuran amphibians in state of Paraná, southern Brazil

Abstract: The state of Paraná, located in southern Brazil, was originally covered almost entirely by the Atlantic Forest biome, with some areas of Cerrado savanna. In the present day, little of this natural vegetation remains, mostly remnants of Atlantic Forest located in the coastal zone. While some data are available on the anurans of the state of Paraná, no complete list has yet been published, which may hamper the understanding of its potential anuran diversity and limit the development of adequate conservation measures. To rectify this situation, we elaborated a list of the anuran species that occur in state of Paraná, based on records obtained from published sources. We recorded a total of 137 anuran species, distributed in 13 families. Nineteen of these species are endemic to the state of Paraná and five are included in the red lists of the state of Paraná, Brazil and/or the IUCN. Two anuran species were categorized as Near Threatened by the IUCN and 27 species were listed as Data Deficient in one or more lists. According to IUCN 49.6% of the anuran species recorded had their population trends stable, 19% in declined, only 1.4% is increased and 20.4% had your population trends unknown. We also recorded the occurrence in Paraná of the exotic invader anuran Lithobates catesbeianus. We consider our list of species to be a relatively reliable estimate of the anuran diversity of the Brazilian state of Paraná, although new species records are expected, mainly because there are many regions that have not yet been sampled.

Psychrophrynella glauca sp. n., a new species of terrestrial-breeding frogs (Amphibia, Anura, Strabomantidae) from the montane forests of the Amazonian Andes of Puno, Peru

We describe a new species of small strabomantid frog (genus Psychrophrynella) from a humid montane forest in the Peruvian Department of Puno. Specimens were collected at 2,225 m a.s.l. in the leaf litter of primary montane forest near Thiuni, along the Macusani-San Gabán road, in the province of Carabaya. The new species is assigned to Psychrophrynella on the basis of morphological similarity, including presence of a tubercle on the inner edge of the tarsus, and call composed of multiple notes. We also include genetic distances for 16S rRNA partial sequences between the new species and other strabomantid frogs. The species with lowest genetic distances are Psychrophrynella chirihampatu and Psychrophrynella usurpator. Psychrophrynella glauca sp. n. is readily distinguished from the three other species of Psychrophrynella (Psychrophrynella bagrecito, P. chirihampatu, and P. usurpator) by its small size, and by having belly and ventral surfaces of legs reddish-brown or red, and chest and throat brown to dark brown with a profusion of bluish-gray flecks. The new species is only known from its type locality. With the discovery of P. glauca, the geographic distribution of Psychrophrynella is extended to the Department of Puno, where it was no longer represented after the description of the genus Microkayla. Furthermore, the Cordillera de Carabaya is the only mountain range known to be home to four of the seven genera of Holoadeninae (Bryophryne, Microkayla, Noblella, and Psychrophrynella), suggesting an intriguing evolutionary history for this group in southern Peru.