New chelid turtle with a flattened skull from the Late Cretaceous of Northern Patagonia, Argentina

The skull morphology of fossil chelids is poorly known because their fossil record is scarce. Here, we describe a new genus and species of flat-headed chelid turtle based on a partial skull. The remains derive from the Maastrichtian (Late Cretaceous) upper section of the Allen Formation at Morales Quarry, near General Roca city in the Río Negro province of Argentina. The new taxon belongs to the flat-headed long-necked chelid group Hydromedusinae and preserves the anterior part of the skull, which is unknown in other members of the clade. Despite being incomplete, the new fossil provides valuable information about cranial morphology in extinct chelid turtles.