The Dipsadidae contains more than 700 extant species belonging to 92 genera and is the largest family of American snakes. In this work, we built a data set including two mitochondrial genes (12S and 16S rRNA) for 125 dipsadid taxa belonging to 59 genera, in order to gain further insights on the phylogenetic relationships of this large group at the subfamilial and generic levels. Among dipsadines, the monotypic genus Nothopsis is the sister-group to Leptodeira. Among xenodontines, the monophyly of seven previously recognized tribes (Alsophiini, Elapomorphini, Hydropsini, Philodryadini, Pseudoboini, Tachymenini and Xenodontini) is confirmed. Among Xenodontini, the genus Liophis is paraphyletic with respect to Erythrolamprus and Umbrivaga and workers should be aware of the inadequacy of the current taxonomy. Finally, the following genera could not confidently be allocated to the above tribes: Caaeteboia, Echinantera and Taeniophallus, Tropidodryas, Manolepis and Pseudalsophis, Xenopholis, Psomophis, Hydrodynastes, Conophis and Crisantophis.

AimMapping Amazonian biodiversity accurately is a major challenge for integrated conservation strategies and to study its origins. However, species boundaries and their respective distribution are notoriously inaccurate in this region. Here, we generated a georeferenced database of short mtDNA sequences from Amazonian frogs, revised the species richness and the delimitation of bioregions of the Eastern Guiana Shield and estimated endemism within these bioregions. LocationAmazonia, with a focus on the Eastern Guiana Shield. Taxon studiedAmphibia: Anura. MethodsWe used an extensive DNA-based sampling of anuran amphibians of Amazonia using nextgeneration sequencing to delimit Operational Taxonomic Units (OTU) and their distribution. We analysed this database to infer bioregions using Latent Dirichlet Allocation modelling. We then compared endemism within these bioregions based on our results and the current IUCN database, and inferred environmental variables that contributed the most to the biogeographic pattern. ResultsThe recognized anuran species richness within the focal area increased from 440 species currently listed by the IUCN Red List to as much as 876 OTUs with our dataset. We recovered eight bioregions, among which three lie within the Eastern Guiana Shield. We estimated that up to 82% of the OTUs found in this area are endemic, a figure three times higher than the previous estimate (28%). Environmental features related to seasonal precipitations are identified as playing an important role in shaping Amazonian amphibian bioregions. Main conclusionsOur results have major implications for defining future conservation priorities of this vast area given that endemism in most Amazonian bioregions is vastly underestimated, and might therefore hide a large portion of threatened species. Moreover, these findings raise concern about meta-analyses based on public databases within Amazonia dealing with poorly known groups.

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We describe a new Pristimantis from French Guiana, northern South America, which is mainly distinguished from known phenotypically related congeners (i.e. species from the polyphyletic unistrigatus species group) occurring at low and middle elevations in the Guiana Shield by the combination of a distinct tympanum, a lower ratio of tibia vs. hand length, a reddish groin region, and a distinct advertisement call consisting of clusters of generally four short notes. The new species inhabits pristine primary forests on the slopes of isolated massifs reaching more than 400 m elevation, and seems not to occur below ca. 200 m above sea level. Such a sharp altitudinal limit suggests a strong influence of thermal variation on the distribution of the species, and therefore a potential sensitivity to climate change. With only nine isolated populations documented so far, the new species should be prioritized for conservation. Historical climate fluctuations during the Quaternary are likely responsible for the distribution pattern of the new species.