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Re: Megalancosaurus, Longisquama & other oddballs



On Mon, 19 Mar 2001, Ken Kinman wrote:

> Mike,
>     I would agree that something like Crocodylotarsi would be preferable to
> Pseudosuchia.  However, Avemetatarsalia is probably at best the paraphyletic
> mother group that gave rise to Crocodylotarsi (not sister groups), and
> Avemetatarsalia may well turn out to be actually polyphyletic.

Not if phylogenetically defined as Clade(_Passer_, _Iguanodon_ <--
_Crocodylus_). It would be either monophyletic, or invalid in the unlikely
event that _Crocodylus_ falls inside Clade(_Passer_ + _Iguanodon_). If
_Pterosauria_ turn out not to belong, so be it.

>       And I also agree that Ornithischia is preferable to Predentata,
> although I'm not particularly crazy about either one of them.

_Predentata_ is, in all fairness, a great name, since it sums up the one
trait completely unique to the group. But, yes, you really can't supplant
such a well-restablished name as _Ornithischia_, IMHO.

> I'm just crossing my fingers and hoping Phytodinosaura might be a good
> clade.  Time will tell.

Even if it is, _Ornithischia_ should be a subclade of it. The definition
really should be changed to Clade(_Iguanodon_ <-- _Megalosaurus_,
_Saltasaurus_), or something similar. _Phytodinosauria_ could be
Clade(_Iguanodon_, _Saltasaurus_ <-- _Megalosaurus_) (invalid under most
phylogenies).

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