Biogeography and Phylogenetics of Neotropical Freshwater Fishes

The Neotropical region harbours the richest freshwater fish fauna on Earth, shaped by a complex interplay of geological, climatic and evolutionary processes. Over the last 100 million years, Andean uplift, marine transgressions and the formation of mega-wetland systems have repeatedly reorganised river networks, driving episodes of allopatric speciation and extinction. Time-calibrated molecular phylogenies now allow reconstruction of lineage diversification across major river basins, revealing Western Amazonia as both a cradle of rapid in situ diversification and a source of dispersal to adjacent regions. Comparative analyses of independent fish clades highlight convergent patterns of phylogenetic endemism and the importance of river capture in forging basin-specific assemblages. These insights inform conservation prioritisation amid ongoing habitat fragmentation, hydropower development and climate change.

Research from Nature Portfolio

Recent research has combined palaeogeographic reconstructions with mechanistic simulations to quantify the impact of Andean uplift on river network evolution. By modelling dispersal, extinction and speciation over an 80-million-year timescale across shifting river networks, researchers have shown that repeated small river capture events in western Amazonia catalysed exceptionally high diversification rates. These findings refine our understanding of how mountain building and dynamic palaeohydrography sculpted present-day species richness gradients and underscore the secondary role of Miocene mega-wetlands.

Biogeography and Phylogenetics of Neotropical Freshwater Fishes publication trend

The graph below shows the total number of articles in biogeography and phylogenetics of neotropical freshwater fishes across all publications each year (not limited to Nature Index journals).

Technical terms

Biogeography: The study of the distribution of species and ecosystems through geographic space and geological time.

Phylogenetics: The analysis of evolutionary relationships among organisms using molecular or morphological data to infer branching patterns.

River capture: A geological process in which a river or stream is diverted into a neighbouring drainage, often by headwater stream erosion.

Allopatric speciation: The divergence of populations into distinct species due to geographic isolation that prevents gene flow.

Phylogenetic endemism: A measure of the concentration of unique evolutionary lineages restricted to a particular geographic area.

References

1. Freshwater fish diversity in the western Amazon basin shaped by Andean uplift since the Late Cretaceous. Nature Ecology & Evolution (2023).
2. Landscape dynamics and diversification of the megadiverse South American freshwater fish fauna. Proceedings of the National Academy of Sciences of the United States of America (2023).
3. Speciation in Coastal Basins Driven by Staggered Headwater Captures: Dispersal of a Species Complex, Leporinus bahiensis, as Revealed by Genome-wide SNP Data. Systematic Biology (2023).