A multidisciplinary team has managed to identify a new species of prehistoric sea turtle on the coasts of Chubut.
The specimen, named Helianthochelys redondita, lived approximately 20 million years ago. It was found about 40 kilometers from Trelew, as part of a paleontological campaign led by CONICET-CENPAT.
The discovery is key to understanding the evolution of sea turtles and the morphological changes they underwent over millions of years.
The fossil includes an almost complete shell, skull fragments, and postcranial remains, making it one of the southernmost and best-preserved records of the dermochelid lineage.
Helianthochelys redondita: name, morphology, and evolutionary context
The generic name comes from the Greek terms helios (sun) and anthos (flower), alluding to the arrangement of the shell ossicles, resembling a sunflower. The epithet redondita refers to Estancia La Redonda Chica, the place where the remains were found.
“This species belongs to the dermochelid family, the same group that includes the modern leatherback turtle (Dermochelys coriacea),” explained paleontologist Juliana Sterli.
The specimen would have reached similar dimensions to modern leatherback turtles, with a shell of over 2 meters long. Current dermochelids are excellent divers, capable of diving to depths of over 2,000 meters, feeding on jellyfish, and maintaining a body temperature higher than the surrounding water, a phenomenon known as gigantothermy.
“Probably this fossil turtle shared similar habits,” Sterli added. During that period, between 23 and 13 million years ago, the climate in these latitudes was warmer, and there are records indicating the presence of dermochelids even in Antarctica.
Paleontological campaign, rescue, and fossil transport
The specimen was discovered in 2016, on the edge of a deep canyon near the coastline, almost 2 km from the nearest road. In 2017, specialists from the Egidio Feruglio Museum (MEF) protected the remains with a plaster cast, due to the risk of erosion and exposure.
The extraction was postponed for several years due to logistical difficulties and the pandemic. In 2021, the definitive transport began. To move the cast —heavy and in hostile terrain—, MEF technicians designed a special vehicle called “tortumóvil”, adaptable as a sled or wheeled stretcher.
“Each day we advanced between 100 and 300 meters, in groups of six people,” Sterli recounted. In 2024, a road was built to drag the tortumóvil with machinery and finally lift it with a tripod onto a pickup truck. After almost a decade, the turtle received its official name.
Collaborative work and institutional value
The fossil, now exhibited at the MEF, is the result of the effort of more than 30 people, including the landowner Ana María Aguirre, rural workers, volunteers, technicians, and researchers from the MEF and CONICET-CENPAT. The project was made possible thanks to the support of the National Agency for the Promotion of Science and Technology, CONICET, and MEF.
The research team was composed of Juliana Sterli and Evangelos Vlachos (CONICET–MEF), José Ignacio Cuitiño (CONICET-CENPAT), Ignacio A. Cerda (CONICET–UNRN, Institute of Paleobiology and Geology Research, Provincial Museum Carlos Ameghino, Cipolletti), and Mónica Romina Buono (CONICET-CENPAT).
