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Environmental gradients (EG) related to climate, topography and vegetation are among the most important drivers of broad scale patterns of species richness. However, these different EG do not necessarily drive species richness in similar ways, potentially presenting synergistic associations when driving species richness. Understanding the synergism among EG allows us to address key questions arising from the effects of global climate and land use changes on biodiversity. Herein, we use variation partitioning (also know as commonality analysis) to disentangle unique and shared contributions of different EG in explaining species richness of Neotropical vertebrates. We use three broad sets of predictors to represent the environmental variability in (i) climate (annual mean temperature, temperature annual range, annual precipitation and precipitation range), (ii) topography (mean elevation, range and coefficient of variation of elevation), and (iii) vegetation (land cover diversity, standard deviation and range of forest canopy height). The shared contribution between two types of EG is used to quantify synergistic processes operating among EG, offering new perspectives on the causal relationships driving species richness. To account for spatially structured processes, we use Spatial EigenVector Mapping models. We perform analyses across groups with distinct dispersal abilities (amphibians, non-volant mammals, bats and birds) and discuss the influence of vagility on the partitioning results. Our findings indicate that broad scale patterns of vertebrate richness are mainly affected by the synergism between climate and vegetation, followed by the unique contribution of climate. Climatic factors were relatively more important in explaining species richness of good dispersers. Most of the variation in vegetation that explains vertebrate richness is climatically structured, supporting the productivity hypothesis. Further, the weak synergism between topography and vegetation urges caution when using topographic complexity as a surrogate of habitat (vegetation) heterogeneity.

The genus Scinax currently includes more than 120 species, recovered in two major clades, the S. catharinae and the S. ruber clades. The latter comprises 75 species, most of which remain unassigned to any species groups, while 12 are included in the S. rostratus and S. uruguayus groups. In this paper we present a taxonomic review of the two species currently included in the S. uruguayus group, discussing some putative phenotypic synapomorphies of this group. Although S. pinima and S. uruguayus have been considered as distinct species, this has been based on scant evidence, and several authors doubted of their distinctiveness. Our study of available specimens of S. pinima and S. uruguayus corroborates that both are valid and diagnosable species based on phenotypic evidence. Furthermore, our results show that S. pinima previously known only from its type locality, has a much widespread distribution than previously thought (including the Brazilian states of Paraná, Santa Catarina, and Rio Grande do Sul), which, added to the biological information presented here allows to suggest the removal of this species from the \"Data Deficient\" IUCN Red List category to \"Least Concern\". Also, we describe a new species formerly reported as S. aff. pinima and S. uruguayus from NE Argentina and some localities from the Brazilian State of Rio Grande do Sul. All species are diagnosed and characterized using adult and larval morphology, osteology, vocalizations, cytogenetics, and natural history.

Taxonomists always have had intense discussions about how species should be delimited and recently many studies have used integrative approaches by combining molecular, morphological, and bioacoustic data. Although these studies are paramount for understanding species diversity, few of them actually formalize species delimitations to the final step of nomenclatural acts. Historically, the Neotropical frog genus Adenomera has been considered as a difficult taxonomic group because it comprises many morphologically similar species exhibiting high levels of intraspecific polymorphism. A recent work using molecular data shed light on the phylogenetic relationships within the genus and identified several lineages that may correspond to undescribed species but did not delimit species boundaries. In the Atlantic Forest, a clade formed by A. marmorata and two putative species (Adenomera sp. J and Adenomera sp. K) were identified. In this paper, we combine morphological, acoustic, and molecular data in order to evaluate species limits within this Atlantic Forest Adenomera clade. We provide a redescription of A. marmorata and restrict its type locality to the Tijuca Massif, in the Municipality of Rio de Janeiro, Brazil. Our results do not support A. marmorata and the two candidate species as diagnosable distinct species. Therefore A. marmorata corresponds to a species with pronounced morphological and acoustic variation in the genus and a complex phylogeographic structure.

The taxonomic status of a disjunctive population of Phyllomedusa from southern Brazil was diagnosed using molecular, chromosomal, and morphological approaches, which resulted in the recognition of a new species of the P. hypochondrialis group. Here, we describe P. rustica sp. n. from the Atlantic Forest biome, found in natural highland grassland formations on a plateau in the south of Brazil. Phylogenetic inferences placed P. rustica sp. n. in a subclade that includes P. rhodei + all the highland species of the clade. Chromosomal morphology is conservative, supporting the inference of homologies among the karyotypes of the species of this genus. Phyllomedusa rustica is apparently restricted to its type-locality, and we discuss the potential impact on the strategies applied to the conservation of the natural grassland formations found within the Brazilian Atlantic Forest biome in southern Brazil. We suggest that conservation strategies should be modified to guarantee the preservation of this species.

[This corrects the article DOI: 10.1371/journal.pone.0222131.].

The delimitation of cryptic species is a challenge for biodiversity conservation. Anurans show high cryptic diversity levels, and molecular species delimitation methods could help identify putative new species. Additionally, species delimitation approaches can provide important results for cryptic species conservation, with integrative methods adding robustness to results. was described from Santa Catarina Island (SCI), southern Brazil. More recently, some inventories indicated continental populations supposedly similar in morphology to it. If these records are confirmed as it would likely change its endangered status on National Red List, removing the species from conservation agendas. We investigated the threatened frog , to evaluate if the continental populations belong to this species or if they form an undescribed species complex. We used coalescent, distance, and allele-sharing-based species delimitation methods and integrative analyses of morphometric and bioacoustics traits to test evolutionary independence between from SCI, Arvoredo Island, and continental populations. is restricted to Santa Catarina Island, while the five remaining lineages should be further investigated through a taxonomic review. Our results point to a small geographic range of . Additionally, the species occurs in isolated fragments of forest in SCI surrounded by expanding urban areas, confirming its status as Endangered. Thus, the protection and monitoring of and the taxonomic description of the continental and Arvoredo Island candidate species should be priorities.

We present a synthesis of anuran diversity and distribution in the Mantiqueira Mountain Range, one of the largest mountain ranges occurring within the Atlantic Forest biome of Brazil. We assembled a species list based on the examination of 16,893 specimens housed in 10 herpetological collections and data compiled from the literature. We developed minimum convex polygons for each species to determine their degree of association with the mountain range, and assessed distribution patterns considering species presence–absence in nearby geomorphological units. The northern and southern sectors of the mountain range were examined for differences in species composition, accounting for possible effects of the main vegetation types of the range. We recorded 234 anuran species (∼23% of total anuran richness for Brazil), including 143 core species, 89 species of marginal occurrence, and 2 species with an undetermined degree of association because of taxonomic uncertainties. Of these species, 91 were widespread and occur throughout the Atlantic Forest and in other regions, 53 were not widespread but range into neighboring geomorphological units, and 88 were endemic species. The northern and southern sectors of the mountain range differed in species composition, which was influenced by the different vegetation types. Thirty-nine endemic species were restricted to the southern sector, whereas 45 occurred only in the northern sector, indicating that these sectors potentially represent distinct biogeographic units with regard to the anurans. We found 14 species that are listed among the categories of both global and national lists of threatened species and 10 species whose most recent records date from at least 30 yr ago. Our study confirms that the Mantiqueira Range is a critical region for anuran endemism and conservation in the Atlantic Forest, and provides a baseline for future biogeographic, taxonomic, and macroecological studies.

Helicops is a genus of Neotropical watersnakes containing 16 species. Based on morphological (scale counts, dentition, coloration, and hemipenis anatomy) and genetic data (16S rRNA and C-mos genes), we identify a new species of this genus. The new taxon is diagnosed by having 17-17-15 dorsal scale rows; 111–117 ventral plates; 41–56 subcaudals without keels; nasal entire; 18–21 + 2 maxillary teeth; hemipenis bilobed, semicalyculate, and semicapitate; dorsum uniformly medium brown or dark brown; venter cream or light brown with two medial rows of black markings, usually semilunar in shape. The new species occurs from southeastern to northern Minas Gerais state, Brazil.

The bromeligenous genus Crossodactylodes, endemic to the Atlantic Forest domain and the “campo rupestre” ecosystem in Brazil, currently comprises five named species. Three additional putatively new species have already been proposed in a recent study based on mitochondrial and nuclear markers. Here we employ phenotypic data to corroborate the distinctiveness of one of these lineages, and describe it as a new species, from the Espinhaço Mountain Range in the municipality of Itamarandiba, state of Minas Gerais, southeastern Brazil. We also provide information on its natural history and conservation status. The new species is diagnosable from its congeners by a combination of characters, including the presence of vocal slits in adult males, the orange coloration of discs on fingers and toes, and the presence of vomerine odontophores. The new species is the second Crossodactylodes to be reported for the campo rupestre and it was only recorded in a small forest patch composed of low trees, shrubs, mosses, lichens, and a high density of bromeliads.

Four species of pumpkin toadlets are currently recognized by the extreme condition of hyperossification in the skull and vertebral column within the genus Brachycephalus. In addition to their larger body size, relative to other congeneric species, Brachycephalus darkside, Brachycephalus ephippium, Brachycephalus garbeanus, and Brachycephalus margaritatus share remarkable osteological features, such as the large paravertebral plates forming an ornamented dorsal bone shield, visible through the integument. We add to the current knowledge of this group by analyzing its diversity and describing a new hyperossified species from some important Atlantic Forest remnants in southeastern Brazil, including those bordering São Paulo, the largest and most populous city in South America. The new species is diagnosed by a combination of morphological, osteological, and bioacoustic characters, with further evidence of mtDNA sequences to confirm its distinction from the other congeners. The parotic and paravertebral bone plates externally bordered with a rough and pale contour can readily distinguish the new species from the other hyperossified species within Brachycephalus. The new species is widely distributed along the Serra do Mar mountain range, including the regionally named Serra de Paranapiacaba, in elevations from 700 to 1000 m above sea level (a.s.l.), in the central coast of the state of São Paulo, southeastern Brazil. We discuss valuable morphological characters within this group of species, reinforce the need for further studies, and highlight the relevance of protected areas for biodiversity conservation in metropolitan regions.