The oldest record of gnathostome fossils from Greece: Chondrichthyes from the Lopingian of Hydra Island

摘要

The Permian deposits of Hydra Island, Greece, have been known for over a century and host some of the best-studied and most diverse invertebrate assemblages of the ancient Paleotethys Ocean. However, until now, no Paleozoic fossils of jawed vertebrates had been reported from Greece. Recent fieldwork on Hydra Island brought to light rare cartilaginous fish remains, including a tooth belonging to an unknown hybodontiform shark, as well as an unidentifiable dermal denticle of an euselachian shark. Despite similarities with iconic Paleozoic and Mesozoic durophagous euselachians, the Hydriot tooth likely corresponds to a new species, but is provisionally left in open nomenclature until more material becomes available. The new chondrichthyan fossils from Hydra Island correspond to one of the few Lopingian (late Permian) occurrences known from the Paleotethys. Moreover, they constitute the oldest record of jawed-vertebrate fossils from Greece, predating younger occurrences by more than 50 million years.