Article: The Callovian (Middle Jurassic) teleosaurid marine crocodiles from central England
Susan M. Adams-Tresman
For many years the taxonomy of the Callovian marine crocodiles of the genera Steneosaurus and Mycterosuchus has been in a state of confusion. Bivariate and principal coordinate analyses are used in an attempt to identify cranial characters for discriminating species. Many of the characters used previously to define five species of Steneosaurus and one of Mycterosuchus are shown to be individually variable. Only two Callovian species can now be identified on the basis of their skull proportions and numbers and form of their teeth: S. leedsi incorporates specimens previously assigned to S. leedsi Andrews, 1909, and Mycterosuchus nasutus Andrews, 1913; S. durobrivensis includes 5. durobrivensis Andrews, 1909, S. obtusidens Andrews, 1909, S. hulkei Andrews, 1913, and S. depressus Phizackerley, 1951.