Orthaspidoceras

Orthaspidoceras is an extinct ammonoid cephalopod genus belonging to the family Aspidoceratidae. These nektonic carnivores lived during the Jurassic period, Kimmeridgian age.
Description.
Shells of "Orthaspidoceras" are medium or large-sized, with a diameter reaching about . These shells are relatively involute and thick, with a quadrate-rounded or depressed whorls. The ornamentation consists of a row of coarse tubercles and fine streaks.
Distribution.
Jurassic deposites of Italy, Mexico, Switzerland and Yemen 