Phylogeny-based species delimitation and integrative taxonomic revision of the Hyalinobatrachium fleischmanni species complex, with resurrection of H. viridissimum (Taylor, 1942)

Water Pollution Increases the Risk of Chytridiomycosis in Mexican Amphibians

Chytridiomycosis is affecting amphibians worldwide, causing the decline and extinction of several amphibian populations. The disease is caused by the fungus Batrachochytrium dendrobatidis (Bd), a multihost pathogen living in freshwater habitats. While several environmental factors have been associated with the prevalence of Bd and its virulence, the effects of water quality on the pathogen are not clear yet. Some evidence suggests that water pollution may reduce amphibians' immune response and increase prevalence of Bd. To explore this hypothesis, we analyzed the relationship between water quality and the presence of Bd by using spatial data mining of 150 geolocations of Bd in amphibians from 9 families where Bd positive specimens have been previously reported, and water quality in 4,202 lentic and lotic water bodies in Mexico from 2010 to 2021. Our model showed that in the 3 main families where Bd was recorded, its presence is high in locations with low water quality, i.e., water polluted likely contaminated with urban and industrial waste. Using this model, we inferred areas suitable for Bd in Mexico; mainly in poorly studied areas along the gulf and on the pacific slope. We further argue that actions to reduce water pollution should become an integral part of public policies to prevent the spread of Bd and protect amphibians from this deadly pathogen.

Delimitation despite discordance: Evaluating the species limits of a confounding species complex in the face of mitonuclear discordance

The delimitation of species is an essential pursuit of biology, and proper taxonomies are crucial for the assessment and conservation management of organismal diversity. However, delimiting species can be hindered by a number of factors including highly conserved morphologies (e.g., cryptic species), differences in criteria of species concepts, lineages being in the early stages of the speciation or divergence process, and discordance between gene topologies (e.g., mitonuclear discordance). Here we use a taxonomically confounded species complex of toads in Central America that exhibits extensive mitonuclear discordance to test delimitation hypotheses. Our investigation integrates mitochondrial sequences, nuclear SNPs, morphology, and macroecological data to determine which taxonomy best explains the divergence and evolutionary relationships among these toads. We found that a three species taxonomy following the distributions of the nuclear SNP haplotypes offers the best explanation of the species in this complex based off of the integrated data types. Due to the taxonomic instability of this group, we also discuss conservation concerns in the face of improper taxonomic delimitation. Our study provides an empirical and integrative hypothesis testing framework to assess species delimitation hypotheses in the face of cryptic morphology and mitonuclear discordance and highlights the importance that a stable taxonomy has over conservation-related actions.

Revision of the Laonice bahusiensis complex (Annelida: Spionidae) with a description of three new species

The morphological reexamination of specimens previously identified as Laonice bahusiensis Sderstrm, 1920 from North European and Mediterranean collections, supported by the molecular analysis of freshly collected material, enabled the recognition of four different species in the region: the genuine L. bahusiensis, L. irinae n. sp. from North European waters, and L. grimaldii n. sp. and L. mediterranea n. sp. from the Mediterranean Sea. The morphology of these species is described and illustrated, and their distributions are clarified based on old and new materials. A key for their identification is also provided. The Bayesian analysis of the COI sequences (483 bp) showed that these four species form a clade, namely the L. bahusiensis species complex, morphologically characterized by the continuous dorsal crests on postbranchiate chaetigers in the adults. The genetic p-distances between the species of the complex ranged from 13.27% to 17.99%, while the intraspecific variability ranged from 0.6% to 1.57%. Together with the sister species Laonice cirrata (Sars, 1851), the L. bahusiensis complex formed the Laonice (Laonice) clade, which is morphologically characterized by the prostomium fused with the anterior peristomial margin. However, the monophyly of the L. bahusiensis complex, as well as that of the clade Laonice (Laonice), needs to be further supported through the analysis of a greater set of genes from a larger number of species.

The role of Indigenous and Community Conservation Areas in herpetofauna conservation: a preliminary list for Santa Cruz Tepetotutla, Oaxaca Mexico

The montane cloud forests of the Sierra Madre de Oaxaca (SMO) host a remarkable herpetofauna diversity and represent one of the most important areas of endemism for Mexico and Mesoamerica. Although the area has been previously studied, most of the extant records for this group are biased to locations accessed by paved roads. In addition, an important proportion of this territory is conserved by Indigenous and Community Conservation Areas (ICCA), but little information of the species occurring within these areas exists. Therefore, information on the distribution of many endemic taxa in this region to date is either underestimated or incomplete. With the aim of increasing the ecological and distributional knowledge of this group in remote areas, we carried out field surveys in Santa Cruz Tepetotutla Oaxaca, a locality 25 km in a straight line to the closest paved road that conserves 9,670 ha of land through the ICCAs modality. Surveys were made during 2018 and 2019, including both dry and wet seasons. A total of 40 species of amphibians and reptiles were recorded: 32.5% of these records represent distributional range extensions, while 20% represent altitudinal range extensions. A total of 17.5% are records of species under a high risk category, highlighting both the relevance of studying remote areas to increase species population knowledge and the role of community conservation actions for species persistence. Finally, our records include the rediscovery of Rhadinella schistosa, a species undetected for more than 50 years.