 Any saurischian that diverged before the theropod-sauropodomorph split is therefore outside clade Eusaurischia.One alternative hypothesis challenging Seeley's classification was proposed by Robert T. Bakker in his 1986 book "The Dinosaur Heresies".Bakker's classification separated the theropods into their own group and placed the two groups of herbivorous dinosaurs (the sauropodomorphs and ornithischians) together in a separate group he named the Phytodinosauria ("plant dinosaurs").