ARCHOSAUROMORPH CONTENTS

["D.W.Naish" <dwn194@soton.ac.uk>]

> The clade Archosauromorpha includes archosaurs and the following:
> 
> Protorosauria ("first lizards"),
> Rhynchosauria ("beak lizards"),
> and Trilophosauria ("three-crest lizards").

I think the Chirostodera, including thalattosaurs, should be in there too. I can
only guess that they are too aberrant to be including in many 'standard'
cladograms (they _are_ mysteriously left out of many), but they definitely have
the archosauromorph 'gestalt' for me...

> Archosauromorpha, Lepidosauromorpha (lizards, snakes, sphenodonts, 
> ?placodonts, ?plesiosaurs, ?nothosaurs, ?ichthyosaurs), and Eosuchia 
> (early diapsids; paraphyletic, I think, although I do not have specifics)

No way are sauropterygians and/or ichthyosaurs part of the Lepidosauromorpha,
IMHO anyway.

What used to be called 'eosuchians' are now placed variously amongst the
prolacertiform archosauromorphs (e.g. protorosaurs, _Tanystropheus_) and various
of the lepidosauromorphs (esp. the younginiforms). Workers had long been fooled
by superficial similarities, that's a consequence of the 'grade'. Various of the
pterosaurs workers, of course, would have Pterosauria as derived from the
prolacertiforms, so they'd still be archosauromorphs.

Easy words eh?

> Crurotarsi (?"leg ankles"):

That's, sadly, Pseudosuchia nowadays... but then, priority rules don't apply for
higher level taxa!!

I wouldn't be surprised if I'm very much out of date on some of this info,
please post if things are different. On this 'clade-for-disparate-descendants'
thing, creating a Class for Archosauria (meaning Archosauriformes!) relegates
other archosauromorphs to limbo, and creating a paraphyletic class (or several)
for them ignores their affinities both to archosauriforms and, lower down, to
other neodiapsids. It's such a mess, and unresolvable at our level of
understanding. Creating mega-taxa (eg. 'Gigaclass Theropoda) to house other
already higher-rank taxa is ridiculous of course - (hard to find an analogy
here) taxa can still be part of their ancestral group, but evolve enough
disparity to warrant high ranks, as birds do. I can't explain this at all, so
I'll shut up before I make a fool of myself (too late!).

"How are we s'pposed to eat rocks?!"  "I bought ketchup!"

DARREN NAISH