Coelacanth remains from the Late Jurassic–?earliest Cretaceous of Uruguay: the southernmost occurrence of the Mawsoniidae

ABSTRACT Mawsonia, the largest actinistian, was a non-marine form common in continental and estuarine deposits of the Tithonian—Cenomanian of western Gondwana. The genus has been recently reviewed, and only two species are recognized as valid: M. gigas and M. tegamensis. Herein we describe new material that can be referred to this genus, including two basisphenoids, a coronoid, a pterygoid, a metapterygoid, one operculum, and two posparietals. The Uruguayan record represents the southernmost occurrence of Mawsonia and the Mawsoniidae in the world, and strengthens the Late Jurassic—Early Cretaceous age proposed for the unit.