Re: Phytodinosauria status

["T. Mike Keesey" <tmk@dinosauricon.com>]

On Wed, 6 Jun 2001 Dinogeorge@aol.com wrote:

> In a message dated 6/6/01 6:19:09 PM EST, j_mallon@hotmail.com writes:
>
> << I'm just curious as to whether or not anyone still subscribes to Bakker's
>  "Phytodinosauria", as mentioned in his _Dinosaur Heresies_?  This topic
>  doesn't seem to have been brought up within the past few years or so, and as
>  I'm currently discussing the subject with a fellow dino-enthusiast, I
>  thought I might bring it to the attention of the list once again.  Bakker's
>  Phytodinosauria doesn't really seem to have caught on, but are there any
>  legit reasons for this?  Is the clade considered to be monophyletic?  Just
>  curious. >>
>
> Most dinosaur paleontologists think Saurischia and Ornithischia are the
> fundamental dichotomy of Dinosauria, but the 17 or so characters that
> supposedly support this seem very equivocal to me. Just a little nudging of
> the cladogram would move Ornithischia into Saurischia as prosauropod
> descendants (Prosauropoda is a paraphyletic group, I think, and may number
> both ornithischians and herrerasaurians among its Late Triassic descendants)
> closely related to Massospondylidae--which makes a great deal more sense to
> me than leaving ornithischians to evolve a lot of dinosaurian features on
> their own, independently of "saurischians." Then the fundamental dichotomy of
> Dinosauria would be into Phytodinosauria (sauropods, prosauropods,
> ornithischians) and Aves (herrerasaurians, theropods, and birds).
> Phytodinosauria Bakker 1986 was earlier named Ornithischiformes by Michael
> Cooper in 1985.

Let me see if I have this view right by trying to interpret it into a
more cladistic format:

--+=="lagosuchians"
  `--+==basal "prosauropods"
     `--Dinosauria
        |--Theropoda (Aves sensu Olshevsky)
        |  |==certain "prosauropods"
        |  `--+--Eoraptor
        |     `--+--Herrerasauridae
        |        `--Neotheropoda (incl. Aves sensu Chiappe)
        `--Ornithischiformes (=Phytodinosauria)
           |--Sauropodomorpha
           |  |==certain "prosauropods"
           |  `--Sauropoda
           `--Ornithischia
              |--Massospondylidae
              `--+--Lesothosaurus
                 `--Genasauria

Using:

Dinosauria == Clade(Megalosaurus + Iguanodon)
Theropoda == Clade(Megalosaurus <-- Diplodocus*)
Neotheropoda == Clade(Ceratosaurus + Passer)
Ornithischiformes == Clade(Iguanodon, Diplodocus* <-- Megalosaurus)
Sauropodomorpha == Clade(Diplodocus* <-- Megalosaurus, Iguanodon)
Sauropoda == Clade(Diplodocus* + Vulcanodon)
Ornithischia == Clade(Iguanodon <-- Megalosaurus, Diplodocus*)
Genasauria == Clade(Iguanodon + Ankylosaurus)
(* or Saltasaurus or Cetiosaurus or whatever)

Which "prosauropods" would you place in these various areas?

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T. MICHAEL KEESEY
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