Sylvienodus, a new replacement genus for the Cretaceous pycnodontiform fish “Pycnodus” laveirensis

Sylvienodus nov. gen. is erected as replacement for “Pycnodus” laveirensis, from the marine Cenomanian, Late Cretaceous, of Laveiras, Portugal. Significant differences between Sylvienodus and Pycnodus include: absence of dermocranial fenestra, a single premaxillary tooth, simple contact of arcocentra, extremely falcate dorsal and anal fins, lesser enlargement of hypochordal elements on caudal endoskeleton, simpler dorsal ridge scales, oval notch between 1st and 2nd dorsal ridge scales, and a single post-cloacal ventral keel scale. After the removal of the species laveirensis, the genus Pycnodus is considered restricted to the Eocene; its type species, P. apodus, is the only one known from complete specimens. Sylvienodus laveirensis is provisionally assigned to the Pycnodontinae, pending revision of this subfamily.