The first record of a pterothrissin (Albuliformes, Albulidae) from the Muhi Quarry, mid-Cretaceous (Albian-Cenomanian) of Hidalgo, central Mexico

A new albuliform fish Nunaneichthys mexicanus gen. et sp. nov. is described from the Muhi Quarry, AlbianCenomanian of Hidalgo, central Mexico. This species is a member of the subfamily Pterothrissinae, which is distinguished by having the following diagnostic combination of characters: skull roof bones ornamented with fine longitudinal striations, parasphenoid with conical teeth and a rounded tip, mandibles with denticles aligned in a single row, mandibular-quadrate articulation at the level of the posterior half of the orbit, subinferior mouth, preopercle somewhat expanded posteroventrally, and a long dorsal fin starting at the level of the 14th vertebra. The phylogenetic analysis indicates that this new species is closely related to the genus Pterothrissus on the basis of sharing a parietal pierced by a supraorbital sensory canal and crossed by anterior pit line, a parietal shorter than it is wide, and supratemporal commissure that runs for at least part of the trajectory trough parietals and/or supraoccipital. The new species is the earliest reported occurrence of a Pterothrissinae from the mid-Cretaceous of North America. The fossil record indicates that these bonefishes inhabited the Western Tethys sea during the Albian-Cenomanian.