Saturday, December 10, 2016

Hopeful Dinosaurs - Updated!

Silesaurus opolensis, by Scott Hartman--used with permission.
We’re going to start this discussion with an assumption so that I don’t have to go back a hundred years and talk about the history of dinosaur phylogeny: Dinosauria is a monophyletic group, and it consists of the Saurischia (Theropoda + Sauropodomorpha) and Ornithischia (everyone else). I’ll also invoke Robert Bakker’s bizarre suggestion that the Theropoda was separate from a (Sauropodomorpha + Ornithischia) group he called the “Phytodinosauria” because they all ate plants, had similar teeth and, back in 1986, Segnosaurus was thought to be maybe a missing link between prosauropods and early ornithischians (details in The Dinosaur Heresies). You'll see why soon.