New Pacu Species Discovered in brazils Xingu River Basin, Highlighting amazon Biodiversity Crisis
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Altamira, Pará, Brazil – A previously unkown species of pacu, Myloplus sauron, has been formally described by researchers, underscoring the vast, and rapidly diminishing, biodiversity of the Amazon rainforest.The discovery, published this week in Neotropical Ichthyology, comes as a stark reminder that a meaningful portion of the region’s freshwater fish remain undocumented, hindering effective conservation efforts.
The Amazon River Basin is a global hotspot for freshwater fish diversity,yet a recent assessment reveals that approximately 42% of its freshwater fish species are still unknown to science. This means nearly one in three fish encountered by researchers could represent a species yet to be formally named and studied. This lack of baseline data presents a major challenge to conservationists attempting to understand and mitigate the impacts of human activities on vulnerable populations.
The Urgent Need for Amazon Fish Inventory
The Xingu River Basin, where M. sauron was found, is especially rich in unique aquatic life.Already home to over 600 documented fish species, the basin harbors seventy species found nowhere else on Earth. The discovery of M. sauron emphasizes the critical need for comprehensive species inventories before further habitat loss occurs.
The research team, led by Dr. Carlos Eduardo da Silva at the Museu Paraense Emílio Goeldi in Belém,Pará,focused their efforts on the stretch of the Xingu River below the Tamaracá waterfall,located within the Indigenous Territory of the Kayapó people. Specimens of M. sauron were consistently found in the swift-flowing waters and rocky crevices near the waterfall, suggesting a preference for areas with strong currents and ample algae growth. The fish’s physical characteristics – a deep body and robust pectoral fins – support this observation, indicating an adaptation for navigating and feeding in turbulent waters.
Combining Conventional Taxonomy with Modern Genetics
Identifying M. sauron as a distinct species required a multi-faceted approach. Researchers meticulously analyzed dozens of physical traits, including fin ray counts, body shape, and scale patterns. Specifically, thay noted a distinct black stripe differentiating it from closely related pacu species. Crucially, this morphological data was combined with DNA barcoding, a technique utilizing short sequences of mitochondrial DNA to confirm genetic divergence.
the genetic analysis definitively distinguished M. sauron from its closest relatives, Myloplus aylan and Myloplus schomburgkii. This combined evidence provided the researchers with the confidence to formally describe M.sauron as a new species. The DNA barcoding was conducted at the Laboratório de Genética Molecular (molecular Genetics laboratory) at the universidade Federal do Pará in Belém.
Threats to Myloplus sauron and the Xingu River Ecosystem
Despite its relatively wide distribution along several hundred miles of the Xingu River, M. sauron is already facing threats from human activities.The construction of large hydroelectric dams upstream, such as the Belo Monte Dam completed in 2019, disrupts natural seasonal flood cycles vital for pacu breeding. Moreover, unregulated gold mining operations release significant amounts of silt and mercury into the river, polluting the water and impacting aquatic life.
Currently,the species is listed as “Least Concern” by the research team,but Dr.Collins, a contributing researcher, stresses the importance of early recognition for proactive conservation. the discovery of M. sauron underscores the value of DNA barcoding as a tool for identifying hidden biodiversity before it’s lost. Each new genetic barcode added to global databases refines our understanding of Amazonian diversity and directs future research towards areas with the highest potential for uncovering further unknown species.The Xingu River Basin, covering approximately 511,000 square kilometers (197,300 square miles), is a critical ecosystem facing increasing pressure from deforestation, agriculture, and infrastructure development. The ongoing documentation of its biodiversity, like the discovery of M. sauron, is essential for informing effective conservation strategies and protecting this irreplaceable natural resource.
Sources:
Original Article: https://www.earth.com/news/new-pacu-fish-species-discovered-in-brazils-xingu-river-basin/
Research Paper: https://www.scielo.br/j/ni/a/fFG9HTqKTjCs4Z4W3MxwSLJ/?lang=en
