HP Stephan Pickering wrote:
>I would, also, place Megalosauridae within Avetheropoda (Megalosaurus = Torvosaurus, >Eustreptospondylus, Metriacanthosaurus, Poecilopleuron, Gasosaurus?, Piatnitzkysaurus?)
What do mean with this segment, that Megalosaurus is synonymous to the other genera you mentioned in the same sentence? Maybe an assignment of Poecilopleuron to this genus is possible, but referral to the genus Torvosaurus is certainly impossible, purely based on the following characters: the age difference. Megalosaurus is known from the Oxfordian, while Torvosaurus is from Kimmeridgian-Tithonian, with will separate them for a few milion years. Secondly, their humeri don't compare that well: the humeral crest is relatively bigger in Megalosaurus (could be due to the their size differences between the genera) than it is in Torvosaurus. Also, the shape of this crest is more box-like than the clearly more triangular shape of Torvosaurus. Combine this with the relative longer shaft in Torvosaurus , the humerus don't compare well. The tip of the dentary is broken of in T.tanneri but it still shows that the angle it makes is higher than it is the case with Megalosaurus, the latter also differs in the more pointed end. The interdental plates are also fused in Torvosaurus, which is a derived character, which M.bucklandii lacks.
>, with the "spinosaurs" as a closely related group.
>Although it would create enormous taxonomic headaches, I believe it possible Allosaurus and >Streptospondylus and Neovenator could be synonymized.
Ehhhh.... right. Streptospondylus is a rather fragmentary genus, yet it is diagnosible, but luckily, inspite of it's fragmentary state, the pubic "boot" has been preserved. Not that it is any "boot-like", more "fist-like" IYAM and exactly there lies the difference. When we compare the different designs of the pubic-"boot", it is noticable that the morphology of this element is very similair in Allosaurus and Neovenator and both are different from Streptospondylus. I would like to see what characters are used to unite them in the genus Streptospondylus (which should than be the rightfull name for Allosaurus, since it has clear priority) first before we take this seriously.