Wikipedia
Gamerabaena is an extinct genus of baenid turtle which existed in North Dakota during the late Cretaceous period. It is known from a single fragmentary skull that was found in the Maastrichtian-age Hell Creek Formation. It contains the species Gamerabaena sonsalla. Gamerabaena is similar to the genus Palatobaena, but it differs in its lack of a posterior expansion of the triturating (or chewing) surface, a somewhat rectangular skull, and a wide angle between the maxillae. Gamerabaena also has a lingual ridge on the inner side of the jaw that is not seen in Palatobaena.
Gamerabaena is considered the sister taxon of Palatobaena and shares features with both Palatobaena and Plesiobaena. These features, which include slightly upturned eye sockets, are seen as intermediate between the two other genera. While Gamerabaena is known only from the skull, it may belong to the same species as "Baena" hayi, which is known primarily from the shell.