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The gut microbiome composition of terrestrial vertebrates is known to converge in response to common specialized dietary strategies, like leaf-eating (folivory) or ant- and termite-eating (myrmecophagy). To date, such convergence has been studied in mammals and birds, but has been neglected in amphibians. Here, we analysed 15 anuran species (frogs and toads) representing five Neotropical families and demonstrated the compositional convergence of the gut microbiomes of distantly related myrmecophagous species. Specifically, we found that the gut microbial communities of bufonids and microhylids, which have independently evolved myrmecophagy, were significantly more similar than expected based on their hosts' evolutionary divergence. Conversely, we found that gut microbiome composition was significantly associated with host evolutionary history in some cases. For instance, the microbiome composition of Xenohyla truncata, one of the few known amphibians that eat fruits, was not different from those of closely related tree frogs with an arthropod generalist diet. Bacterial taxa overrepresented in myrmecophagous species relative to other host families include Paludibacter, Treponema, and Rikenellaceae, suggesting diet-mediated selection and prey-to-predator transmission likely driving the observed compositional convergence. This study provides a basis for examining the roles of the gut microbiome in host tolerance and sequestration of toxic alkaloids from ants and termites.

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Intending to increase the knowledge about cytogenetics of Physalaemus and the sparsely studied P. gracilis group, we analyzed the karyotypes of P. carrizorum, P. gracilis, P. lisei, and P. sp. aff. gracilis. We studied chromosome morphology, heterochromatin patterns, Ag-NORs location and mapped the repetitive DNA sequence PcP190. All species showed diploid karyotypes composed of 22 bi-armed chromosomes and similar C- bands and Ag-NOR patterns. C-bands were mainly centromeric and pericentromeric; non-centromeric C-bands were detected on the telomeres of pair 1 in P. lisei, although polymorphic, and interstitially on pair 10 of P. gracilis. This last character is useful to distinguish P. gracilis from its sibling species P. sp. aff. gracilis. The Ag-NOR sites were detected on the long arms of chromosome pair 8 but with a variable position among species. Clusters of PcP190 showed centromeric and pericentromeric positions coincident with conspicuous C-bands, on pairs 2 and 9 in P. gracilis and P. sp. aff. gracilis, pair 3 in P. carrizorum, and pair 7 in P. lisei. These results significantly increase the knowledge about Physalaemus cytogenetics and encourage further studies on the satellite PcP190 in other genera of Leiuperinae to better understand its taxonomic distribution and the evolutionary dynamics.

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In this work, we show that Bufo levicristatus Boettger, 1885 is a senior synonym of Bufo scitulus Caramaschi Niemeyer, 2003, and not a junior synonym of Bufo ornatus Spix, 1824, as previously considered. In addition, we present evidence that Bufo scitulus Caramaschi Niemeyer, 2003 complies with the International Code of Zoological Nomenclature requirements for a reversal of precedence over the name Bufo levicristatus Boettger, 1885, and so the name Bufo scitulus is to be maintained for this species.

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The South American and West Indian Casque-headed Treefrogs (Hylidae: Hylinae: Lophyohylini) include 85 species. These are notably diverse in morphology (e.g. disparate levels of cranial hyperossification) and life history (e.g. different reproductive modes, chemical defences), have a wide distribution, and occupy habitats from the tropical rainforests to semiarid scrubland. In this paper, we present a phylogenetic analysis of this hylid tribe based on sequence fragments of up to five mitochondrial (12S, 16S, ND1, COI, Cytb) and six nuclear genes (POMC, RAG-1, RHOD, SIAH, TNS3, TYR). We included most of its species (> 96%), in addition to a number of new species. Our results indicate: (i) the paraphyly of Trachycephalus with respect to Aparasphenodon venezolanus; (ii) the nonmonophyly of Aparasphenodon, with Argenteohyla siemersi, Corythomantis galeata and Nyctimantis rugiceps nested within it, and Ap. venezolanus nested within Trachycephalus; (iii) the polyphyly of Corythomantis; (iv) the nonmonophyly of the recognized species groups of Phyllodytes; and (v) a pervasive low support for the deep relationships among the major clades of Lophyohylini, including C. greeningi and the monotypic genera Itapotihyla and Phytotriades. To remedy the nonmonophyly of Aparasphenodon, Corythomantis, and Trachycephalus, we redefined Nyctimantis to include Aparasphenodon (with the exception of Ap. venezolanus, which we transferred to Trachycephalus), Argenteohyla, and C. galeata. Additionally, our results indicate the need for taxonomic work in the following clades: (i) Trachycephalus dibernardoi and Tr. imitatrix; (ii) Tr. atlas, Tr. mambaiensis and Tr. nigromaculatus; and (iii) Phyllodytes. On the basis of our phylogenetic results, we analyzed the evolution of skull hyperossification and reproductive biology, with emphasis on the multiple independent origins of phytotelm breeding, in the context of Anura. We also analyzed the inter-related aspects of chemical defences, venom delivery, phragmotic behaviour, co-ossification, and prevention of evaporative water loss.

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Cytogenetic analyses were performed on specimens of Leptodactylus bufonius from different localities in Argentina. Mitotic chromosomes were studied with Giemsa and differential staining techniques (Ag-NOR, C-banding, and CMA3/DAPI) and fluorescence in situ hybridization with the 18S DNAr probe. All specimens showed karyotypes with 2n = 2x = 22 and FN = 44. Secondary constrictions were present in the long arm of chromosome pair 8, coincident with Ag-NOR and hybridization signals of the 18S DNAr probe. The C-banding technique evidenced an important amount of heterochromatin with a sex-linked pericentromeric band in the short arm of chromosome pair 4. This heterochromatic band was heteromorphic in males but present in both homologues of females, and it was CMA3 positive (DAPI negative) at fluorescence staining. The occurrence of heteromorphic XY sex chromosomes in L. bufonius is the second known case in Leptodactylus and the fifth within the speciose family Leptodactylidae.

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Zootaxa is a mega-journal that since its inception, 20 years ago, has contributed to the documentation of the planet's biodiversity. Its role concerning terrestrial vertebrates has been crucial especially for amphibians, which are the most threatened class of vertebrates. As current editors of the Amphibia section, we reviewed the state of knowledge of taxonomic publications on amphibians over the last two decades (from 2001 to 2020). Our review reveals that 2,533 frogs, 259 salamanders, and 55 caecilians have been named in these 20 years, mainly in the tropical regions of South America, Asia, and Africa. More than half (57%) of these species descriptions were published in only 10 journals. At least 827 species of the new amphibians (29% of the total) were described in Zootaxa. This mega-journal has served also as a place of publication for monographs and systematic reviews, in addition to short articles documenting the vocalizations of anurans and the morphology of embryos and larvae. Its efficient evaluation process, the freedom of manuscript length, including full-color figures, and free of cost for the authors, has made Zootaxa a favorite for amphibian researchers. In an era of accelerating rates of biodiversity loss, documenting, describing, naming, and proposing evolutionary scenarios for species is, more than ever, an urgent task.

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Liolaemus is the most specious genus of the Squamata lizards in South America, presenting exceptional evolutionary radiation and speciation patterns. This recent diversification complicates the formal taxonomic treatment and the phylogenetic analyses of this group, causing relationships among species to remain controversial. Here we used Next-Generation Sequencing to do a comparative analysis of the structure and organization of the complete mitochondrial genomes of three differently related species of Liolaemus and with different reproductive strategies and ploidy levels. The annotated mitochondrial genomes of ca. 17 kb are the first for the Liolaemidae family. Despite the high levels of sequence similarity among the three mitochondrial genomes over most of their lengths, the comparative analyses revealed variations at the stop codons of the protein coding genes and the structure of the tRNAs among species. The presence of a non-canonical dihydrouridine loop is a novelty for the pleurodonts iguanians. But the highest level of variability was observed in two repetitive sequences of the control region, which were responsible for most of the length heterogeneity of the mitochondrial genomes. These tandem repeats may be useful markers to analyze relationships of closely related species of Liolaemus and related genera and to conduct population and phylogenetic studies.

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In this paper we present a phylogenetic analysis of the treefrogs of the Boana pulchella Group with the goals of (1) providing a rigorous test of its monophyly; (2) providing a test of relationships supported in previous studies; and (3) exploring the relationships of the several species not included in previous analyses. The analyses included>300 specimens of 37 of the 38 species currently included in the group, plus 36 outgroups, exemplars of the diversity of Boana and the other genera of the hylid tribe Cophomantini. The dataset included eight mitochondrial genes (12S, 16S, CytB, COI, ND1, tRNAIle, tRNALeu, and tRNAVal) and five nuclear genes (RHO, TYR, RAG-1, CXCR4, SIAH1). The phylogenetic analyses recover the monophyly of the B. pulchella Group with lower support than previous studies, as a result of the inclusion of the B. claresignata Group, which is recovered as its sister taxon. Within the B. pulchella Group, the inclusion of almost all species of the group had little impact on previous notions of its phylogeny, except for the rejection of the hypothesized B. polytaenia Clade (B. goiana and B. phaeopleura are nested in the clade here called the B. prasina Clade), which is redefined. Phylogenetic support is strong for five major clades, which collectively include all but three of the species sampled: the B. balzani Clade (B. aguilari, B. balzani, B. gladiator, B. melanopleura, B. palaestes), the redefined B. polytaenia Clade (B. botumirim, B. buriti, B. cipoensis, B. jaguariaivensis, B. leptolineata, B. polytaenia, B. stenocephala, and two undescribed species), the B. prasina Clade (B. bischoffi, B. caingua, B. cordobae, B. goiana, B. guentheri, B. marginata, B. phaeopleura, B. prasina, B. pulchella, and one undescribed species), the B. riojana Clade (B. callipleura, B. marianitae, B. riojana), and the B. semiguttata Clade (B. caipora, B. curupi, B. joaquini, B. poaju, B. semiguttata, B. stellae, and two undescribed species). The monophyly of the B. prasina + B. riojana Clades, and that of the B. polytaenia + B. semiguttata Clades are well-supported. The relationships among these two clades, the B. balzani Clade, B. ericae + B. freicanecae, and B. cambui (representing the deepest phylogenetic splits within the B. pulchella Group) are recovered with weak support. We discuss the phenotypic evidence supporting the monophyly of the B. pulchella Group, and the taxonomy of several species, identifying three new synonyms of Boana polytaenia, one new synonym of Boana goiana, and one new synonym of B. riojana.

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The criteria used by previous authors to define colour aberrancies of snakes, particularly albinism, are varied and terms have widely been used ambiguously. The aim of this work was to review genetically based aberrant colour morphs of wild Neotropical snakes and associated terminology. We compiled a total of 115 cases of conspicuous defective expressions of pigmentations in snakes, including melanin (black/brown colour), xanthins (yellow), and erythrins (red), which involved 47 species of Aniliidae, Boidae, Colubridae, Elapidae, Leptotyphlopidae, Typhlopidae, and Viperidae. Most of them were hypopigmented conditions, mainly amelanism, but also anerythrism, axanthism, hypomelanism, leucism, piebaldism, and albinism (total absence of pigments). Hyperpigmented aberrancies were mostly melanism and xanthism, plus a few instances of erythrism. No associations with diurnality and fossorial behaviour were observed, neither for blanched nor hyperpigmented aberrancies. A discussion of the terms most commonly used for wild snakes is provided, with an account of cases of aberrant colourations in other South American reptiles. Finally, we propose a simple classification framework of wild snake colour aberrancies based on predominant dorsal colour and eye pigmentation for the adoption of a standardized terminology, which may be applicable to other squamates and chelonians. We advocate the use of a more accurate terminology in the scientific literature that would avoid the use of confusing terms like “partial albinism”.

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The hyline tribe Lophyohylini includes 87 species of treefrogs, of which cytogenetics aspects have been studied in less than 20% of them. In order to evaluate the evolution of some of its chromosome characters (NOR position, C-bands, and DAPI/CMA3 bands), we studied the karyotypes of 21 lophyohylines, 16 of them for the first time, and analyzed them in a phylogenetic context. Most species showed similar karyotypes regarding chromosome number (2n = 24) and morphology (FN = 48), excepting Phyllodytes edelmoi and Osteocephalus buckleyi with 2n = 22 (FN = 44) and 2n = 28 (FN = 50), respectively. The NOR location was variable among species and provided valuable phylogenetic information. This marker was located in pair 11 in all species of Trachycephalus, Itapotihyla langsdorffii, and Nyctimantis arapapa, representing the plesiomorphic condition of Lophyohylini. Besides, other apomorphic states were recovered for the clades comprising N. rugiceps and N. siemersi (NOR in pair 5), and Dryaderces pearsoni, Osteocephalus, and Osteopilus (NOR in pair 9). Phyllodytes presented variation for NORs position; they were in pair 2 in P. edelmoi, pair 7 in P. melanomystax, and pair 8 in P. gyrinaethes and P. praeceptor. Polymorphisms in size, number, and activity of this marker were observed for N. siemersi, Osteocephalus fuscifacies, and some species of Trachycephalus. Remarkably, in N. siemersi NORs were detected on a single chromosome in the two specimens studied by this technique, raising the question of how this complex polymorphism is maintained. Interstitial telomeric sequences were found in P. edelmoi, P. melanomystax, and Osteocephalus buckleyi, and their presence seems to be not related to the chromosome reorganization events. Finally, some species showed spontaneous rearrangements, possibly as a consequence of an uncommon phenomenon in anuran cytogenetics: the presence of fragile sites or secondary constrictions not associated with NORs. We propose that this rare feature would have played an important role in the evolution of this group of frogs. From the evidence obtained in this and previous studies, we conclude that Lophyohylini presents a complex chromosome evolution.

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