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Subterranean estuaries are coastal ecosystems characterized by vertically stratified groundwater. The biota within these ecosystems is relatively understudied due to the inherent difficulty of accessing such extreme environments. The fauna inhabiting these ecosystems is considered vulnerable to extinction, and the presence of cryptic species has major implications for research and conservation efforts. Most species lack molecular data; however, the evaluation of genetic data for some taxa has revealed that undocumented species are common. This study employs molecular species delimitation methods and DNA barcoding through the analysis of publicly and newly generated sequences, including individuals from type localities and non-crustacean phyla; the latter are typically overlooked in biodiversity assessments of subterranean estuaries. We analysed 376 cytochrome c oxidase subunit I (COI) gene sequences and 154 16S rRNA gene sequences. The COI sequences represented 32% of previously described species and 50% of stygobiont species from the Yucatan Peninsula and Cozumel Island, while sequences of the 16S rRNA represented 14% of described species and 22% of stygobionts. Our results revealed cryptic genetic lineages and taxonomic misidentification of species. As several species from these ecosystems are recognized as endangered, the use of molecular approaches will improve biodiversity estimates and highlight overlooked cryptic lineages in need of evaluation of conservation status.
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This content will become publicly available on December 6, 2025
Time-calibrated phylogeny of neotropical freshwater fishes
Neotropical Freshwater Fish (NFF) fauna exhibits the greatest phenotypic disparity and species richness among all continental aquatic vertebrate faunas, with more than 6,345 species distributed across the mostly tropical regions of Central and South America. The last two decades have seen a proliferation of molecular phylogenies, often at the species level, covering almost all 875 valid NFF genera. This study presents the most comprehensive genome-wide, time-calibrated phylogenetic hypothesis of NFF species to date, based on DNA sequences generated over decades through the collaborative efforts of the multinational ichthyological research community. Our purpose is to build and curate an extensive molecular dataset allowing researchers to evaluate macroevolutionary hypotheses in the NFF while facilitating continuous refinement and expansion. Using thousands of DNA sequences from dozens of studies, we compiled a supermatrix of 51 markers for 5,984 taxa, representing 3,167 NFF species. Based on this dataset, we built the most species-rich time-calibrated phylogeny of the NFF taxa to date, summarizing the collective efforts of the ichthyological research community since the midpoint of the last century. We provide a summary review of this remarkable evolutionary history and hope this dataset provides a framework for forthcoming studies of the NFF fauna, documenting compelling, emergent patterns in the world’s most diverse continental vertebrate fauna.
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- Award ID(s):
- 2318917
- PAR ID:
- 10569558
- Publisher / Repository:
- Frontiers
- Date Published:
- Journal Name:
- Frontiers in Bioinformatics
- Volume:
- 4
- ISSN:
- 2673-7647
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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