Article: The Callovian (Middle Jurassic) marine crocodile Metriorhynchus from central England
For many years the taxonomy of the Callovian marine crocodile genus Metriorhynchus 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 eight species of Metriorhynchus are shown to be individually variable or continuously variable. Only two Callovian species can now be identified on the basis of their skull proportions: M. superciliosus incorporates specimens previously assigned to M. superciliosum de Blainville, 1853, M. moreli E. E. Deslongchamps, 1867, M. leedsi Andrews, 1913, and M. laeve Andrews, 1913; M. brachyrhynchus includes M. brachyrhynchus E. E. Deslongchamps, 1867, Suchodus durobrivense Lydekker, 1890, M. cultridens Andrews, 1913, and M. casamiquelai de Gasparini and Diaz, 1977.