Osteology of Cavinichthys pachylepis gen. and sp. nov. (Teleostei, Crossognathiformes, Pachyrhizodontidae) from Pietraroja (Lower Cretaceous, Campania, south Italy)

Abstract

Cavinichthys pachylepis gen. and sp. nov., a fossil pachyrhizodontid fish from the marine Albian deposits (Lower Cretaceous) of Pietraroja (Campania, southern Italy), is described in details. The new genus differs from the other members of the family by the minute teeth ranged in wide patches on its jaws. The pterotic is devoid of posterior pointed process. The premaxilla is short and triangular in shape. The unique supramaxilla is narrow and extremely elongate. The first two infraorbitals are fused together, while the three large posterior infraorbitals are separated. The anterior extremity of the large supraorbital reaches the first infraorbital. There is no antorbital. The ventral branch of the preopercle is strongly reduced. The opercle is large and the subopercle small. The first preural centrum and the two ural centra are autogenous but reduced in size. The two ventral hypurals are fused together but not to the first ural centrum. The first uroneural has a broadened anterior extremity but is not forked. Cavinichthys pachylepis occupies a basal position in the phylogenetic tree of the Pachyrhizodontidae.