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

Abstract

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

“…Corcovado, however, is one locality of paratypes of B. hermogenesi and Paraty were also cited as a place of occurrence of B. hermogenesi in the original description of this species (Giaretta & Sawaya, 1998). The species of the B. didactylus group that occurs closest to Rio de Janeiro/São Paulo border, excluding B. hermogenesi and B. sulfuratus, is B. didactylus, in Vila Dois Rios, Ilha Grande, municipality of Angra dos Reis, Rio de Janeiro (Bornschein, Pie & Teixeira, 2019). The Trilha do Corisco is distant from Vila Dois Rios 59 km in a straight line.…”

“…Advertisement calls analyzed of samples from Trilha do Corisco and Corcovado (in part. ), two localities previously considered as occurrence of B. hermogenesi (Giaretta & Sawaya, 1998;Verdade et al, 2008;Pie et al, 2013Pie et al, , 2018bBornschein et al, 2016a;Bornschein, Pie & Teixeira, 2019; Table 1), have reveal substantial differences to made us to considerer that represents other species, unidentified, but not B. sulfuratus (Tables 2 and 3). The call from this third species has two notes forming note groups, exceptionally three, and includes notes with a high number of pulses (up to 16; Tables 2 and 3).…”

“…The genus Brachycephalus Fitzinger, 1826 includes 36 small diurnal anuran species that live in the leaf litter across the Brazilian Atlantic Rainforest (Bornschein, Pie & Teixeira, 2019). Most species present small geographic distributions, restricted to one or a few adjacent mountaintops (Pie et al, 2013;Bornschein et al, 2016a;Bornschein, Pie & Teixeira, 2019).…”

“…Most species present small geographic distributions, restricted to one or a few adjacent mountaintops (Pie et al, 2013;Bornschein et al, 2016a;Bornschein, Pie & Teixeira, 2019). Brachycephalus has been divided in three phenetic groups, based on body shape and presence/absence of dermal co-ossification (Ribeiro et al, 2015), and presence/ absence of linea masculinea (Pie et al, 2018b): the B. ephippium group, with 12 species distributed from Espírito Santo and Minas Gerais south to São Paulo, southeastern Brazil (Bornschein, Pie & Teixeira, 2019); the B. pernix group, with 19 species distributed in Paraná and Santa Catarina, southern Brazil (Bornschein, Pie & Teixeira, 2019); and the B. didactylus group, with four species commonly known as flea toads and distributed throughout much the Atlantic Forest of Brazil, from Bahia to Santa Catarina, northeastern, southeastern, and southern Brazil (Bornschein, Pie & Teixeira, 2019). Members of the B. didactylus species group (sensu Ribeiro et al, 2015;Pie et al, 2018a;Bornschein, Pie & Teixeira, 2019) are distinguished by their leptodactyliform body shape and the absence of dermal ossification and absence of linea masculinea.…”

“…Brachycephalus has been divided in three phenetic groups, based on body shape and presence/absence of dermal co-ossification (Ribeiro et al, 2015), and presence/ absence of linea masculinea (Pie et al, 2018b): the B. ephippium group, with 12 species distributed from Espírito Santo and Minas Gerais south to São Paulo, southeastern Brazil (Bornschein, Pie & Teixeira, 2019); the B. pernix group, with 19 species distributed in Paraná and Santa Catarina, southern Brazil (Bornschein, Pie & Teixeira, 2019); and the B. didactylus group, with four species commonly known as flea toads and distributed throughout much the Atlantic Forest of Brazil, from Bahia to Santa Catarina, northeastern, southeastern, and southern Brazil (Bornschein, Pie & Teixeira, 2019). Members of the B. didactylus species group (sensu Ribeiro et al, 2015;Pie et al, 2018a;Bornschein, Pie & Teixeira, 2019) are distinguished by their leptodactyliform body shape and the absence of dermal ossification and absence of linea masculinea. The B. ephippium species group includes species with bufoniform body shape, presence of dermal ossification and absence of linea masculinea, and, finally, the B. pernix species group includes species equally with bufoniform body shape but without dermal ossification and with linea masculinea (Ribeiro et al, 2015;Pie et al, 2018a).…”