Discovering the Largest Fossil River Dolphin in the Amazonian Basin In the vast and enigmatic Amazon rainforest, a team of international researchers has made a remarkable discovery that sheds new light on the ancient aquatic life that once thrived in this region.
The team, led by the University of Zurich (UZH), has uncovered the largest fossil river dolphin ever found, a species that lived 16 million years ago in the proto-Amazonian landscape. The newly discovered species, named “Pebanista yacuruna” in honor of a mythical aquatic people believed to inhabit the Amazon basin, measured between 3 to 3.5 meters in length, making it the largest known river dolphin to have ever existed.
Remarkably, this ancient giant is not directly related to the modern-day Amazon river dolphins, but rather represents the last survivor of a different group of cetaceans that once roamed our planet. The Pebanista dolphin belongs to the Platanistoidea, a group of dolphins that were once common in the world’s oceans between 24 and 16 million years ago.
Researchers believe that their original marine ancestors invaded the prey-rich freshwater ecosystems of the proto-Amazon region and adapted to this new environment. 16 million years ago, the Peruvian Amazon looked very different from what it is today, says lead author Aldo Benites-Palomino from the UZH Department of Paleontology. Much of the Amazon lowland was covered by a vast system of lakes and swamps called Pebas.
This landscape included aquatic, semi-aquatic, and terrestrial ecosystems (such as swamps and floodplains) and stretched across what is now Colombia, Ecuador, Bolivia, Peru, and Brazil. As the Pebas system began to give way to the modern Amazon around 10 million years ago, the new habitats caused the disappearance of Pebanista’s prey, leading to the giant dolphin’s extinction.
This opened an ecological niche that was then exploited by the ancestors of the modern Amazon river dolphins (Inia), which were also facing extinction in the oceans due to the rise of new cetacean species, such as modern ocean dolphins. We discovered that its size is not the only remarkable aspect, says Benites-Palomino. With this fossil record from the Amazon, we expected to find close relatives of the modern Amazon river dolphin, but instead, the closest relatives of Pebanista are the river dolphins of South Asia (genus Platanista).
Pebanista and Platanista share highly developed facial crests, specialized bony structures associated with echolocation, the ability to “see” by emitting high-frequency sounds and listening to their echoes, which they rely heavily on for hunting.
For river dolphins, echolocation or biosonar is even more critical as the waters they inhabit are extremely turbid, which hinders their vision, explains Gabriel Aguirre-Fernández, a researcher at UZH who also participated in this study. The long snout with many teeth suggests that Pebanista fed on fish, as do other river dolphin species today.
After two decades of work in South America, we had found several giant forms from the region, but this is the first dolphin of its kind, adds Marcelo R. Sánchez-Villagra, director of the UZH Department of Paleontology. We were particularly intrigued by its peculiar biogeographic history over deep time.
The Amazon rainforest is one of the most challenging regions for paleontological fieldwork. Fossils are only accessible during the dry season, when river levels are low enough to expose the ancient fossil-bearing rocks. If these fossils are not collected in time, the rising water levels during the rainy season will wash them away, and they will be lost forever.
The holotype, the single physical specimen on which the description and naming of a new species is based, of Pebanista was found in 2018, when the lead author of the study was still a university student.
The expedition, led by Peruvian paleontologist Rodolfo Salas-Gismondi, a former postdoctoral fellow at the UZH Department of Paleontology, traveled more than 300 kilometers along the Napo River. Dozens of fossils were discovered and collected, but the biggest surprise was waiting at the end of the expedition, after nearly three weeks of exploration: the discovery of the massive dolphin skull, cataloged as MUSM 4017, which has been permanently deposited in the Natural History Museum of Lima.
Sources
University of Zurich | Benites-Palomino, A, Aguirre-Fernández, G., Baby, P. et al., (2024). The largest freshwater odontocete: A South Asian River dolphin relative from the Proto-Amazonia. Science Advances. Doi:10.1126/sciadv.adk6320
- Share on:
Discover more from LBV Magazine English Edition
Subscribe to get the latest posts sent to your email.
A Shipwreck from the 6th Century BC, Stone and Iron Anchors, Found Off the Southern Coast of Sicily
A highly significant archaeological discovery has come to light in the waters of Santa Maria del Focallo, in the municipality of Ispica, Ragusa province, Sicily. During an underwater excavation campaign,…
A heroon with intact tombs filled with luxurious jewels and lions sculpted in Pentelic marble, found in the ancient Greek city of Ripes in Achaea
At the beginning of October, the systematic archaeological excavation season concluded on the Trapezá plateau, located eight kilometers southwest of Aigio, Greece. This site is identified with the ancient city…
Statue Possibly Representing Cleopatra VII and Numerous Coins Featuring Her Effigy Found at the Temple of Taposiris Magna, West of Alexandria
The Egyptian-Dominican archaeological mission, led by Dr. Kathleen Martínez in collaboration with the National University Pedro Henríquez Ureña (UNPHU), has made new discoveries at the Temple of Taposiris Magna, located…
Roman Soldier Flaccus’ Tomb Discovered in the Netherlands, Dating to the Late 1st Century BCE
In late November 2024, during archaeological investigations conducted in Heerlen (Netherlands), an exceptional discovery was made: the tomb of a Roman soldier named Flaccus. This find, dating to the late…
The Mystery of the Mardaites: The Christian Highlanders Who Maintained Their Autonomy Between Byzantium and the Caliphate
In the province of Hatay, in southern Turkey, there is a mountain range locally known as Nur Dağları. Arabs call it Jabal al-Lukkam, and in Spanish, its Greek name, Amanus,…
The Jaxartes River, the Battle Where Alexander Defeated the Scythians Using Catapults, Wounded and with Nearly His Entire Army Sick with Dysentery
As its name indicates, the Spanish Cape of Finisterre (finis terrae) was considered in Antiquity as the westernmost limit of the known world. But where was the eastern border located…
Nature of the Enigmatic “Armas de la tierra” of the Coronado Expedition in the 16th Century Revealed
Recent research has unveiled the nature of the weaponry used by Francisco Vázquez de Coronado’s expedition (which crossed the present-day U.S. states of Arizona, New Mexico, Texas, Oklahoma and Kansas),…
A Megalography Depicting a Rare Mythological Scene of Achilles and Bronze Statuettes Found in a Roman “Domus” in Reims
The urban organization of Durocortorum, the Gallo-Roman city now known as Reims in France, faithfully adhered to the principles of Roman urbanism. The city was divided into blocks bounded by…
Neolithic Rondel Found in Poland Reveals These Ceremonial Centers May Have Been Managed by Organizations Similar to Secret Societies 7,000 Years Ago
An archaeological discovery in the locality of Nowe Objezierze, in the northwest of Poland, has led to a significant breakthrough in understanding the Neolithic societies of Central Europe. An interdisciplinary…
New Geoarchaeological Evidence Challenges the Identification of Kalkriese Hill as the place of the Battle of the Teutoburg Forest
Kalkriese Hill, located in northwestern Germany, has been identified for decades as a potential site of the historic Battle of the Teutoburg Forest in 9 CE, a decisive confrontation between…
Something went wrong. Please refresh the page and/or try again.
