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We describe a new species of Chiasmocleis from the Amazonian forest of Peru. The new species is characterized by its medium size (snout-to-vent length = 18.2-20.8 mm in females, and 16.5 mm in one male), hands and feet with slightly developed fridges in females (more developed in male), and presence of a femoral line in all individuals. We also infer its phylogenetic position using DNA sequences of fragments of the mitochondrial genes for 16S rRNA and cytochrome oxidase subunit 1 (COI), and describe the mineralized skeleton through 3D models generated by computed tomography (CT-scan). Based on our results, we discuss the variation of some osteological characters traditionally used in the systematics of the genus.

We quantitatively describe for the first time the advertisement call of Chiasmocleis (Syncope) carvalhoi using recordings  of five specimens from northern Peruvian Amazonia. The advertisement call is characterized by a single, short, tonal, and high-pitched note. Call duration ranges between 0.03-0.06 s and its dominant frequency between 7.12-7.92 kHz. The lack of pulses within notes distinguishes C. (Syncope) carvalhoi from all congeneric species except C. (Syncope) antenori, C. (Syncope) parkeri and C. (Chiasmocleis) mantiqueira, which can be distinguished by the shorter duration of their notes and silent intervals (in C. (Syncope) antenori and C. (Syncope) parkeri) and by the lower dominant frequency (in C. (Syncope) parkeri and C. (Chiasmocleis) mantiqueira). In addition, based on our collected specimens, we report on and discuss about the variation of some external morphological characters and natural history of C. (Syncope) carvalhoi, including the absence of vocal slits and sacs. Our study reveals a potential association between the absence of vocal slits and sacs, and tonal calls in Chiasmocleis, as well as conflicting morphological diagnostics characters in the literature.

We present data showing that the number of salamander species in Amazonia is vastly underestimated. We used DNA sequences of up to five genes (3 mitochondrial and 2 nuclear) of 366 specimens, 189 corresponding to 89 non-Amazonian nominal species and 177 Amazonian specimens, including types or topotypes, of eight of the nine recognized species in the region. By including representatives of all known species of Amazonian Bolitoglossa, except for one, and 73% of the currently 132 recognized species of the genus, our dataset represents the broadest sample of Bolitoglossa species, specimens, and geographic localities studied to date. We performed phylogenetic analyses using parsimony with tree-alignment and maximum likelihood (ML) with similarity alignment, with indels as binary characters. Our optimal topologies were used to delimit lineages that we assigned to nominal species and candidate new species following criteria that maximize the consilience of the current species taxonomy, monophyly, gaps in branch lengths, genetic distances, and geographic distribution. We contrasted the results of our species-delimitation protocol with those of Automated Barcode Gap Discovery (ABGD) and multi-rate Poisson Tree Processes (mPTP). Finally, we inferred the historical biogeography of South American salamanders by dating the trees and using dispersal-vicariance analysis (DIVA). Our results revealed a clade including almost all Amazonian salamanders, with a topology incompatible with just the currently recognized nine species. Following our species-delimitation criteria, we identified 44 putative species in Amazonia. Both ABGD and mPTP inferred more species than currently recognized, but their numbers (23-49) and limits vary. Our biogeographic analysis suggested a stepping-stone colonization of the Amazonian lowlands from Central America through the Chocó and the Andes, with several late dispersals from Amazonia back into the Andes. These biogeographic events are temporally concordant with an early land bridge between Central and South America (~10-15 MYA) and major landscape changes in Amazonia during the late Miocene and Pliocene, such as the drainage of the Pebas system, the establishment of the Amazon River, and the major orogeny of the northern Andes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

We describe and name the second species of Phyzelaphryne (Brachycephaloidea, Eleutherodactylidae), from northwestern Brazilian Amazonia. Phyzelaphryne nimio sp. nov. is distinguished from its only congener, Phyzelaphryne miriamae, by its smaller body size and the anatomy of the carpal and metacarpal regions, with relatively larger (sometimes fused) supernumerary carpal and metacarpal tubercles. Molecular phylogenetic analyses based on fragments of the mitochondrial genes 16S rRNA and COI suggest that the currently known distribution of the species is restricted to its type locality and other areas within Estação Ecológica Juami-Japurá, state of Amazonas, Brazil. Based on molecular, morphological and bioacoustic evidence, we assigned other specimens recently collected in Parque Nacional do Jaú, state of Amazonas, Brazil, to P. miriamae, extending the species' known geographic distribution north of the Amazon River.