This is one of my favorite dinosaurs - Eustreptospondylus oxoniensis . It's also perhaps one of the most complete theropod fossils from Britain. Eustreptospondylus is a Middle Jurassic 'megalosaur' from the Oxford Clay of Oxfordshire. Now, I'm not much of a historian so I won't claim to know all the details, but it was known for a long time as ' Streptospondylus ' but was subsequently renamed by Walker in 1964 in his paper ' Triassic reptiles from the Elgin area: Ornithosuchus and the origin of carnosaurs '. Ornithosuchu s is nowadays regarded as an archosaur so for some time, I was baffled as to why Walker addressed the question of carnosaur origins by redescribing a Triassic archosaur. However, it appeared I was just being lazy (as usual) as I had not even read the abstract. It is made quite clear that Walker considered Ornithosuchus to be a theropod dinosaur, a primitive carnosaur close to the ancestry of Megalosauridae and Tyrannosauridae. Thu