Giant Flying Squirrels Once Lived in North America – Sci.News

Paleontologists have found the 4.9-million-year-old (Early Pliocene) fossilized remains of the extinct flying squirrel Miopetaurista webbi in Tennessee, the United States. The occurrence of the genus Miopetaurista in eastern North America is puzzling, as it is distant from the known geographical range of the genus and of that of its sister species, the living Petaurista. The researchers hypothesize that Miopetaurista, which was linked to warm forested environments, dispersed into North America via the Bering Land Bridge during the warm phases of the Early Pliocene.Life appearance of the fossil flying squirrel Miopetaurista neogrivensis showing the animal ready to land on a tree branch. Image credit: Oscar Sanisidro / ICP.Miopetaurista webbi soared through the skies over what is now Southern Appalachia, gliding above rhinos, mastodons and red pandas.The new material from this species was discovered at the Gray Fossil Site in Tennessee.“Finding Miopetaurista in North America was quite unexpected as this genus is only known from Eurasia,” said Dr. Isaac Casanovas-Vilar, a paleontologist with the Institut Català de Paleontologia Miquel Crusafont at the Universitat Autònoma de Barcelona.“There had been some uncertain reports from Florida, but the new specimen of the Gray Fossil Site provided new information and helped to confirm that somehow these giant flying squirrels crossed the Bering Land Bridge alongside other mammals about 5 million years ago.”According to the paleontologists, Miopetaurista webbi is probably closely related to Miopetaurista thaleri, the only known Pliocene Eurasian species.“Appalachians today might be tempted to think of these ancient critters as closely related to the squirrels they regularly see,” the researchers said.“But their closest relatives are the giant flying squirrels in Japan, China and Indonesia.”“These giant flying squirrels had a lightweight build, weighing around three pounds — and were quite agile in the treetops.”“When they arrived in what is now Tennessee, the world was much warmer than it is now.”“That warmer climate allowed the squirrel’s ancestors to cross into North America, likely gliding through dense, humid forests like those preserved in the fossil record at the Gray site millions of years ago.”The new specimen may represent the oldest record of the Miopetaurista genus in North America.“As the climate cooled over time, the Pleistocene Ice Ages led to the isolation of these giant flying squirrels in warmer refuges like Florida, and ultimately contributed to their extinction,” said Dr. Montserrat Grau-Camats, also from the Institut Català de Paleontologia Miquel Crusafont at the Universitat Autònoma de Barcelona.“The last American Miopetaurista lived millions of years after all Eurasian species of this genus had disappeared, meaning at the time they were ‘living fossils’.”The team’s work was published in the Journal of Mammalian Evolution._____M. Grau-Camats et al. 2025. Gliding between continents: a review of the North American record of the giant flying squirrel Miopetaurista (Rodentia, Sciuridae) with the description of new material from the Gray Fossil Site (Tennessee). J Mammal Evol 32, 8; doi: 10.1007/s10914-025-09751-w

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