Vastly underestimated species richness of Amazonian salamanders (Plethodontidae: Bolitoglossa) and implications about plethodontid diversification

Diversity and biogeography of South American mud turtles elucidated by multilocus DNA sequencing (Testudines: Kinosternidae)

Kinosternon is the most speciose genus of extant turtles, with 22 currently recognized species, distributed across large parts of the Americas. Most species have small distributions, but K. leucostomum and K. scorpioides range from Mexico to South America. Previous studies have found discordance between mitochondrial and nuclear phylogenies in some kinosternid groups, with the current taxonomy following the nuclear-based results. Herein, based on extended molecular, geographic, and taxonomic sampling, we explore the phylogeographic structure and taxonomic limits for K. leucostomum and the K. scorpioides group and present a fossil-calibrated nuclear time tree for Kinosternon. Our results reveal contrasting differentiation patterns for the K. scorpioides group and K. leucostomum, despite overlapping distributions. Kinosternon leucostomum shows only shallow geographic divergence, whereas the K. scorpioides group is polyphyletic with up to 10 distinct taxa, some of them undescribed. We support the elevation of K. s. albogulare and K. s. cruentatum to species level. Given the deep divergence within the genus Kinosternon, we propose the recognition of three subgenera, Kinosternon, Cryptochelys and Thyrosternum, and the abandonment of the group-based classification, at least for the K. leucostomum and K. scorpioides groups. Our results show an initial split in Kinosternon that gave rise to two main radiations, one Nearctic and one mainly Neotropical. Most speciation events in Kinosternon occurred during the Quaternary and we hypothesize that they were mediated by both climatic and geological events. Additionally, our data imply that at least three South American colonizations occurred, two in the K. leucostomum group, and one in the K. scorpioides group. Additionally, we hypothesize that discordance between mitochondrial and nuclear phylogenetic signal is due to mitochondrial capture from an extinct kinosternine lineage.

Ecological Civilisation and Amphibian Sustainability through Reproduction Biotechnologies, Biobanking, and Conservation Breeding Programs (RBCs)

Intergenerational justice entitles the maximum retention of Earth's biodiversity. The 2022 United Nations COP 15, "Ecological Civilisation: Building a Shared Future for All Life on Earth", is committed to protecting 30% of Earth's terrestrial environments and, through COP 28, to mitigate the effects of the climate catastrophe on the biosphere. We focused this review on three core themes: the need and potential of reproduction biotechnologies, biobanks, and conservation breeding programs (RBCs) to satisfy sustainability goals; the technical state and current application of RBCs; and how to achieve the future potentials of RBCs in a rapidly evolving environmental and cultural landscape. RBCs include the hormonal stimulation of reproduction, the collection and storage of sperm and oocytes, and artificial fertilisation. Emerging technologies promise the perpetuation of species solely from biobanked biomaterials stored for perpetuity. Despite significant global declines and extinctions of amphibians, and predictions of a disastrous future for most biodiversity, practical support for amphibian RBCs remains limited mainly to a few limited projects in wealthy Western countries. We discuss the potential of amphibian RBCs to perpetuate amphibian diversity and prevent extinctions within multipolar geopolitical, cultural, and economic frameworks. We argue that a democratic, globally inclusive organisation is needed to focus RBCs on regions with the highest amphibian diversity. Prioritisation should include regional and international collaborations, community engagement, and support for RBC facilities ranging from zoos and other institutions to those of private carers. We tabulate a standard terminology for field programs associated with RBCs for publication and media consistency.

A new Bolitoglossa (Amphibia, Caudata, Plethodontidae) from the Cordillera Oriental of Colombia

A new salamander species of the genus Bolitoglossa is here described from the cloud forests of the western slopes of the Cordillera Oriental of Colombia, in the Cundinamarca department. The most salient characters of this new species are its numerous maxillary and vomerine teeth, its moderate webbing on hands and feet, its short and robust tail, and its chromatic variation. Based on molecular analyses this new species is assigned to the adspersa species group and its status established as the sister species of B.adspersa, with which it was previously confused. Lastly, the distribution, natural history, and conservation status of the new species are discussed.

Unveiling the evolutionary relationships and the high cryptic diversity in Andean rainfrogs (Craugastoridae: Pristimantis myersi group)

Background

Pristimantis is the most diverse genus of terrestrial frogs. Historically, it has been divided into several phenetic groups in order to facilitate species identification. However, in light of phylogenetic analysis, many of these groups have been shown to be non-monophyletic, denoting a high degree of morphological convergence and limited number of diagnostic traits. In this study, we focus on the Pristimantis myersi group, an assemblage of small rainfrogs distributed throughout the Andes of Ecuador and Colombia, whose external morphology is highly conserved, and its species diversity and evolutionary relationships largely unknown.

Methods

We inferred a new phylogenetic hypothesis for the frog genus Pristimantis, including all available sequences of the mtDNA 16S rRNA, as well as new DNA sequences from 175 specimens. Our sampling included 19 of the 24 species currently recognized as part of the Pristimantis myersi group.

Results

Our new evolutionary hypothesis recovered the P. myersi group as non-monophyletic and composed of 16 species. Therefore, we exclude P. albujai, P. bicantus, P. sambalan, and P. nelsongalloi in order to preserve the monophyly of the group. We discovered at least eight candidate species, most of them hidden under the names of P. leoni, P. hectus, P. festae, P. gladiator, and P. ocreatus.

Discussion

Our results reveal the occurrence of a high level of cryptic diversity to the species level within the P. myersi group and highlight the need to redefine some of its species and reassess their conservation status. We suggest that the conservation status of six species within the group need to be re-evaluated because they exhibit smaller distributions than previously thought; these species are: P. festae, P. gladiator, P. hectus, P. leoni, P. ocreatus, and P. pyrrhomerus. Finally, given that the Pristimantis myersi group, as defined in this work, is monophyletic and morphologically diagnosable, and that Trachyphrynus is an available name for the clade containing P. myersi, we implement Trachyphrynus as a formal subgenus name for the Pristimantis myersi group.

The evolution of reproductive modes and life cycles in amphibians

Amphibians have undergone important evolutionary transitions in reproductive modes and life-cycles. We compare large-scale macroevolutionary patterns in these transitions across the three major amphibian clades: frogs, salamanders, and caecilians. We analyse matching reproductive and phylogenetic data for 4025 species. We find that having aquatic larvae is ancestral for all three groups and is retained by many extant species (33-44%). The most frequent transitions in each group are to relatively uncommon states: live-bearing in caecilians, paedomorphosis in salamanders, and semi-terrestriality in frogs. All three groups show transitions to more terrestrial reproductive modes, but only in caecilians have these evolved sequentially from most-to-least aquatic. Diversification rates are largely independent of reproductive modes. However, in salamanders direct development accelerates diversification whereas paedomorphosis decreases it. Overall, we find a widespread retention of ancestral modes, decoupling of trait transition rates from patterns of species richness, and the general independence of reproductive modes and diversification.

The evolution of parental care in salamanders

Complex parenting has been proposed to contribute to the evolutionary success of vertebrates. However, the evolutionary routes to complex parenting and the role of parenting in vertebrate diversity are still contentious. Although basal vertebrates provide clues to complex reproduction, these are often understudied. Using 181 species that represent all major lineages of an early vertebrate group, the salamanders and newts (Caudata, salamanders henceforth) here we show that fertilisation mode is tied to parental care: male-only care occurs in external fertilisers, whereas female-only care exclusively occurs in internal fertilisers. Importantly, internal fertilisation opens the way to terrestrial reproduction, because fertilised females are able to deposit their eggs on land, and with maternal care provision, the eggs could potentially develop outside the aquatic environment. Taken together, our results of a semi-aquatic early vertebrate group propose that the diversity and follow-up radiation of terrestrial vertebrates are inherently associated with a complex social behaviour, parenting.

A tale of two bellies: systematics of the oval frogs (Anura: Microhylidae: Elachistocleis Parker, 1927)

Oval frogs (Elachistocleis) have a broad geographic distribution covering nearly all of South America and parts of Central America. They also have a large inter- and intraspecific variation of the few morphological characters commonly used as diagnostic traits among species of the genus. Based on molecular data, we provide the most complete phylogeny of Elachistocleis to date, and explore its genetic diversity using distance-based and tree-based methods for putative species delimitation. Our results show that at least two of the most relevant traditional characters used in the taxonomy of this group (belly pattern and dorsal median white line) carry less phylogenetic information than previously thought. Based on our results, we propose some synonymizations and some candidate new species. This study is a first major step in disentangling the current systematics of Elachistocleis. Yet, a comprehensive review of morphological data is needed before any new species descriptions can be properly made.

Species diversity and biogeography of an ancient frog clade from the Guiana Shield (Anura: Microhylidae: Adelastes, Otophryne, Synapturanus) exhibiting spectacular phenotypic diversification

The outstanding biodiversity of the Guiana Shield has raised many questions about its origins and evolution. Frogs of the genera Adelastes, Otophryne and Synapturanus form an ancient lineage distributed mostly across this region. These genera display strikingly disparate morphologies and life-history traits. Notably, Synapturanus is conspicuously adapted to fossoriality and is the only genus within this group to have dispersed further into Amazonia. Moreover, morphological differences among Synapturanus species suggest different degrees of fossoriality that might be linked to their biogeographical history. Through integrative analysis of genetic, morphometric and acoustic data, we delimited 25 species in this clade, representing a fourfold increase. We found that the entire clade started to diversify ~55 Mya and Synapturanus ~30 Mya. Members of this genus probably dispersed three times out of the Guiana Shield both before and after the Pebas system, a wetland ecosystem occupying most of Western Amazonia during the Miocene. Using a three-dimensional osteological dataset, we characterized a high morphological disparity across the three genera. Within Synapturanus, we further characterized distinct phenotypes that emerged concomitantly with dispersals during the Miocene and possibly represent adaptations to different habitats, such as soils with different physical properties.

Two extremely rare new species of fossorial salamanders of the genus Oedipina (Plethodontidae) from northwestern Ecuador

We describe two new species of salamanders of the genus Oedipina, subgenus Oedopinola, from two localities on the northwestern foothills of Ecuador, at elevations between 921 and 1,067 m. These are the southernmost members of the genus. We examined different museum collections and we found just three specimens of Oedipina from Ecuador, obtained throughout the history of herpetological collections in the country. We identify two of the three specimens as new species, but refrain from assigning a specific identity to the third, pending further study. Oedipina villamizariorum sp. n. is a medium-sized member of the genus, with a narrow, relatively pointed head and blunt snout; dorsolaterally oriented eyes, moderate in size; and digits that are moderately long and having pointed tips. Oedipina ecuatoriana sp. n., somewhat larger, has a narrow head and broadly rounded snout; this new species differs from all known Oedipina by the distinctive presence of paired prefrontal bones and a reduced phalangeal formula: 0-0-1-0; 0-1-2-1-1. We provide detailed descriptions of the osteology of both new species. Finally, we present a phylogenetic hypothesis for the genus, including one of the two new species, based on partial sequences of mitochondrial DNA.