Re: [dinosaur] Gnathovorax, new herrerasaurid (open access)

[Tim Williams <tijawi@gmail.com>]

Brad McFeeters <archosauromorph2@hotmail.com> wrote:

> The "compromise" hypothesis, of course, which I don't believe has ever been 
> supported quantitatively, would be that (Ornithischia + Silesauridae) is the 
> sister group
> of Theropoda within Ornithoscelida. I don't know is this is at all plausible, 
> but the silesaurid *Eucoelophysis* was initially described as a neotheropod...

I had the impression that the two hypotheses were mutually
incompatible: silesaurids-as-basal-ornithischians vs
ornithischians+theropods (=Ornithoscelida).  Despite the vexed
taxonomic pedigree of _Eucoelophysis_ (see William Parker's post), it
doesn't seem possible to shoehorn this or any other silesaurid into
the Theropoda.

I'd add that the _Eucoelophysis_ holotype was named by Sullivan &
Lucas (1999), because these authors believed this material
corresponded to the same taxon as the original type material of
_Coelophysis_ (which was found to be undiagnostic).  A neotype for
_Coelophysis_ had previously been declared in 1996, based on a
complete Ghost Ranch specimen (formerly the type specimen of
_Rioarribasaurus_) (ICZN Opinion 1842).
https://urldefense.proofpoint.com/v2/url?u=http-3A__ec2-2D54-2D245-2D84-2D242.us-2Dwest-2D2.compute.amazonaws.com_uploadedfiles_0000_0096_Opinion1842c.pdf&d=DwIBaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=bVrVmqK2JXojf_PzwtCxtyNNHI89XwepItz65WVqOoM&s=YdoJym4WD2LPec6jAAIIcg0ZhaP-xSfhzTs_8quO2KM&e=