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Thousands of species of fish – about 2,500 of them named – call the Amazon River home, but scientists estimate that almost half of the marine creatures lurking in the vast stretch of water remain undiscovered.
While studying piranhas and pacus in an effort to better assess vital fish biodiversity in the 4,000-mile-long (6,400-kilometer-long) river, an international team of researchers has discovered and identified a new species of pacu, piranha relative to a. plant-based diet and humanlike teeth.
Apart from its odd pearly whites, the newly discovered species has striking orange and black markings – including a heavy vertical black bar that runs across its forehead – that resemble the fiery eye symbol of the villain Sauron from JRR Tolkien’s “The Lord of the Rings” by JRR Tolkien. book and film series. The markings inspired the fish’s name, Myloplus sauron, according to a study published Monday in the journal Neotropical Ichthyology.
“The co-authors and I thought (the name) would be a nice idea — it looks like the eye of Sauron,” said study co-author Victória Pereira, a graduate student in biology in Paulista University in São Paulo, Brazil. The researchers hoped the reference to pop music would draw attention to the fish and efforts to protect biodiversity in the Amazon, Pereira added.
The eyed fish isn’t the only animal named after Tolkien’s Dark Lord. A genus of butterflies was found in May 2023 with eye-like spots on its wings, reminding researchers of the well-known symbol from the trilogy. A species of tree frog, a dung beetle and a genus of dinosaur are also named after the character.
The confusion around pacus
In addition to Myloplus sauron, the researchers also discovered the species Myloplus aylan, which they said has a slightly thicker black bar on its side. The genus Myloplus falls within the Serrasalmidae fish family, which consists of piranha and pacu species.
Because piranhas and pacus are closely related and have similar features, differentiating the species can be difficult, the authors noted in the study. Both pacu and piranha species can change appearance during different stages of their lives, and males and females often look different, making it difficult to tell the different species apart, according to the History Museum the Nature London.
Myloplus sauron and Myloplus aylan have flat, blunt teeth used for chewing plants, a stark contrast to the razor-sharp teeth found in piranhas, but similar to their other PACu counterparts. Although some species of piranha are known for their carnivorous diets, all pacus species are primarily herbivores.
Previously, these two new species were grouped with another fish, Myloplus schomburgkii, due to the shared design of the black mark on the rounded body of the fish. However, through closer inspection and DNA analysis, the researchers found that three different species shared the attractive design.
Researchers hope to further study Myloplus sauron and Myloplus aylan to learn more about their evolution and relationship with other species, Pereira said.
“People studying pacus have recognized for some time that multiple species were ‘hiding in plain sight,'” said Matthew Kolmann, an assistant professor in the Department of Biology at the University of Louisville in Kentucky, who has studied the fish. He was not involved in the new study.
“The size of the Amazon and other basins, and their accessibility, make it a place of constant discovery,” Kolmann said in an email. “What this means is that generations of scientists have and will continue to try to increase our knowledge of the area.”
Impact of Pacus on their ecosystem
Pacus are important to their ecosystem mainly because of their role in dispersing seeds through their diet of mostly fruits, making them vital to the growth of rainforest trees and other plants. The fish tend to spread seeds far from their parent plants, helping to expand the forest and limiting diseases that spread easily through crowded trees, Kolmann said.
By discovering and identifying the species that live in certain ecosystems, researchers will be able to guide conservation efforts to protect endangered or threatened animals, Kolmann said. It is especially important for areas such as the Amazon that are threatened by habitat destruction, he said.
“We run the risk of losing thousands, if not thousands, of species before we even know they exist, and by proxy, we never understand how these species contribute to a healthy, functioning ecosystem,” Kolmann said. . “The first step in any future conservation effort is to take an inventory of the species found, where and when.”
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