Abstract Phenotypic traits and genetic variation are fundamental for understanding biological diversity and evolutionary processes. In natural populations, phenotypic novelties are generally expected to align with genetic differentiation, establishing phenotype–genotype relationships. This pattern is evident in Neotropical lizards of the genus Anolis , where traits such as the dewlap and hemipenes play key roles in species recognition and sexual selection, and are often associated with reproductive isolation, genetic structure, and lineage divergence. However, in Anolis mariarum , an Andean species from northern Colombia, previous limited sampling suggested a mismatch between these traits and the mitochondrial DNA (mtDNA) lineages. Here, we analyzed specimens from 41 localities across the species’ range, examining hemipenial morphology, dewlap coloration, phylogenetic signal, and genetic structure using three mitochondrial markers. We identified seven mitochondrial clades within A. mariarum , with divergence partially shaped by Andean topography and genetic distances comparable to those reported among Anolis species and subspecies. Two hemipenial morphologies (types A and B) and three dewlap colour patterns (orange–yellow, orange–pink, reddish) were detected, reflecting notable intraspecific variation. Although both traits showed strong phylogenetic signal, they exhibited weak spatial and genetic structuring, suggesting an early stage of divergence. Because our inferences are based exclusively on mtDNA, these results should be interpreted cautiously and provide only a preliminary framework for investigating the evolutionary processes underlying phenotypic diversification. These results highlight the evolutionary relevance of dewlap and hemipenial traits and emphasize the need for extensive morphological, geographic, and genetic sampling to accurately assess lineage boundaries and uncover patterns and processes leading to enormous diversity in Neotropical fauna.
Abstract The Hengduan Mountains of southwestern China constitute a classic sky-island system shaped by complex topography and climatic history. We investigated the evolutionary history of the shrew tribe Blarinellini using 272 samples representing both genera and all four recognized species. Based on mitochondrial and nuclear sequence data, we reconstructed phylogenetic relationships, estimated divergence times, and examined population genetic structure and ecological niche dynamics. Our results support an early Miocene origin of Blarinellini (~18.2 million years). Population genetic analyses recovered five and four deeply divergent geographic lineages within Blarinella quadraticauda and B. wardi , respectively. Most genetic variation was partitioned among lineages, indicating strong long-term isolation. Lineage distributions closely correspond to major river systems and montane regions, suggesting that the effects of river barriers and sky-island fragmentation may have contributed to the observed patterns of diversification. Ecological niche models identified climatically stable habitats within the Hengduan Mountains across multiple glacial–interglacial cycles, whereas demographic analyses revealed recent expansion in a subset of lineages. Together, these results suggest that river barriers, sky-island fragmentation, and climatic change may have jointly contributed to diversification in Blarinellini, and suggest that evolutionary diversity within the tribe may be substantially underestimated. These findings highlight the dual role of the Hengduan Mountains as both a refuge preserving ancient lineages and a cradle generating new diversity.
Abstract The diamond frogs of the genus Rhombophryne are a poorly understood clade of morphologically diverse frogs native to the humid forests of Madagascar. We here present a monographic revision of the taxonomy and natural history of these frogs. We first provide morphological diagnoses and contents of the established species groups in Rhombophryne. We then integrate molecular phylogenetic data from mitochondrial and nuclear genetic markers, with morphometrics, bioacoustics, and micro-CT-based osteology, to describe seven new species from across Madagascar. This brings the number of species in the genus to 27. We have obtained DNA sequences from name-bearing specimens of 23 of these species, plus topotypical specimens of two further species; we used museomics methods to sequence name-bearing types of three species collected before 1976, as well as several other specimens of interest, allowing us to clarify taxonomic assignment of those individuals. In our treatments of all existing and new species, we provide new insights into their anatomy, diet, ecology, and distribution. We provide the first published key to the genus, which we hope will make their identification more straightforward. Finally, we suggest a revised conservation assessment in light of the data that we present. We estimate 24 of the 27 species to be threatened, with two species (R. kilonjy sp. nov. and R. matavy) probably worthy of being classified as ‘Critically Endangered’. Several candidate species remain taxonomically unaddressed, due to the poor representation of specimens in museum collections. We therefore emphasise the need for increased survey efforts to fill knowledge gaps in both the taxonomy and the natural history of these frogs.
Abstract Mito-nuclear discordance is a well-recognized phenomenon; however, the limited use of nuclear data in rodent systematics has revealed few documented cases. As such, the extent to which discordant gene trees mislead taxonomic schemes remains unclear. Here, we document an example of such discordance in a taxonomic assessment of species boundaries within the subgenus Angelomys of the genus Abrothrix, based on mitochondrial, nuclear (ultraconserved elements, UCEs), and morphological data. Our analyses revealed strong discordance between the mitochondrial tree and the species tree emerging from the UCE dataset. The latter recovered three main lineages within Angelomys, each phenotypically distinct. Therefore, we propose that the taxonomic scheme that best represents the alpha taxonomy of the subgenus Angelomys recognizes three species rather than the two recently proposed. The three species we recognize are Abrothrix (Angelomys) andina, distributed from the highlands of Santiago in central Chile northward along the Pacific coast to southern Peru; Ab. (An.) dolichonyx, a highland species ranging from Mendoza in west central Argentina northward through the high Andean regions of northern Argentina, northern Chile, western Bolivia and southern Peru; and Ab. (An.) olivacea, distributed from lowland areas of central Chile and Mendoza (Argentina), extending southward through the temperate forests, Patagonia, Tierra del Fuego, nearby islands, and reaching Cape Horn. Finally, we designate a lectotype for Hesperomys dolichonyx (= Ab. dolichonyx) and restricted the type locality of Mus andinus (= Ab. andina) to a locality within the general area indicated in the species description and from which the species has been recorded.
Abstract Tadarida brasiliensis is a widespread species ranging from the United States to the southern tip of South America. Population genetics studies have been conducted mainly in the northern populations, with only a few samples from South America being included in previous studies. The study of T. brasiliensis populations is relevant due to their ecological importance as an insectivorous species that consumes agricultural pests and their role as a reservoir of diverse pathogens that may represent a potential risk to humans and other animals. Our objective was to analyze the population genetic structure of T. brasiliensis in Argentina in order to better understand the migration patterns of the species in the southern tip of its distribution, evaluate its genetic variation, and predict the impact on the spread of associated viruses, which has direct application to guide sanitary control strategies. We analyzed samples of 94 individuals from 14 provinces of Argentina and the Autonomous City of Buenos Aires using double digestion restriction site-associated DNA sequencing (ddRADseq) technology to obtain variable nuclear genomic markers (SNPs). The average statistics of 29,715 unlinked SNPs revealed high genetic diversity in the samples and an absence of population structure throughout Argentina, suggesting that the population of T. brasiliensis in Argentina behaves as a single panmictic unit. Demographic analyses indicate that the Argentine population underwent a significant growth, starting at approximately 0.27 million years ago and reaching an estimated current effective population size of 2.7 million. The results of complementary analyses using sequences of the mitochondrial gene cytochrome b are consistent with these conclusions and provide further evidence for a deep split between the populations of North America, South America, and the Caribbean. Our findings are congruent with those of previous studies focusing on North American populations, which also found evidence of population expansion and lack of genetic structure within regional populations.
