Paleontologists have discovered a new species of Maioraniformes turtle, named Patagoniaemys aeschyli, that inhabited northern Patagonia, Argentina, during the Maastrichtian era, just before the catastrophic asteroid impact that led to the extinction of non-avian dinosaurs.
Artist’s impression of Patagoniaemys aeschyli. Image credit: Nawel Vazquez / Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’ / CONICET.
The recently identified turtle species thrived in what is now Patagonia during the Maastrichtian period of the Late Cretaceous, roughly 72 to 67 million years ago.
Patagoniaemys aeschyli is part of a lineage that encompasses some of the rarest turtles ever documented.
These Maioraniformes are highlighted for their heavily armored bodies and, in certain species, distinctive horned skulls.
“Maioraniformes encompass a group of turtles, including the well-known horned species like Nicolamia argentina from Patagonia and Meiolania platypus from Australia,” explained lead author Dr. Federico Agnolin, a paleontologist associated with Bernardino Rivadavia Museum of Natural Sciences, Maimonides University, and CONICET.
“These turtles are recognized from the Lower Cretaceous to the Pleistocene across southern continents, including South America, Australia, and New Caledonia.”
The fossilized remains of Patagoniaemys aeschyli were excavated from the Los Alamitos Formation in Río Negro, Argentina.
The specimen includes parts of a skull, shell fragments, vertebrae, and a limb bone, making it one of the most significant discoveries of meioraniids in the region.
Paleontologists estimate that the carapace of Patagoniaemys aeschyli measured around 80 centimeters (approximately 2.6 feet) in length.
Unlike its later relatives, its shell was wide and relatively low, contrasting with the domed shells often observed in other turtle species.
“The shell is relatively robust at the base of the marginal plates, featuring a series of tough ridges, particularly towards the rear,” noted the researchers.
“The exterior surface of the shell is characterized by small holes and grooves.”
In addition to identifying this new species, the scientists examined how turtles managed to survive during the end-Cretaceous mass extinction event, which occurred 66 million years ago.
The study of Patagonia’s fossil diversity revealed that some turtle lineages endured the transition from the Cretaceous to the Paleogene periods.
The discovery of Patagoniaemys aeschyli confirmed the presence of at least two Maioraniformes in the latest Cretaceous period of southern South America.
“The remarkable taxonomic continuity between Maastrichtian and Danian populations suggests that the end-Cretaceous extinction event did not significantly impact Patagonian turtles, indicating lineage persistence and minimal turnover among southern Chelonians,” concluded the scientists.
A detailed description of this discovery was published in the journal Acta Paleontologica Polonica on March 26, 2026. Read the paper here.
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Federico L. Agnolin et al. 2026. A new species of Maioraniformes turtle from the Maastrichtian region of northern Patagonia, Argentina. Acta Paleontologica Polonica 71 (1): 173-184; doi: 10.4202/app.01268.2025
Source: www.sci.news
