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Re: Coelophysis and Rioarribasaurus



In a message dated 95-10-03 16:59:18 EDT, RaptorRKC@aol.com writes:

>I was browsing around on the internet the other day -- read an article on
>the FRIENDS OF PALEO home page about Coelophysis and Rioarribasaurus.  For
>those who do not yet know of this debate, the original fossil, from which
>Coelophysis was named, was so fragmentary that some believe it couldn't be
>distinguished as a new dinosaur.  So the excellent, complete,
>distinguishable fossils found at Ghost Ranch, POSITIVELY known to be a new
>species of dinosaur, were recently named _Rioarribasaurus colberti_.  Some
>scientists have argued that the type specimen of Coelophysis is not THAT
>bad, and that Coelophysis should be kept at a name. But right now,
>Rioarribasaurus seems to be most favored.

SIGH. Don't tell me someone has already written an article on this. I was
going to use this as the topic of my third Skullduggery article. Well, maybe
they screwed it up.

>So the dinosaur we knew as Coelophysis no longer carries that name -- in
>fact, Coelophysis no longer exists, right?
>
>WRONG. 
>
>The original Coelophysis has been reexamined and scientists seem to have
>come up with a new idea -- Coelophysis (type specimen) and Rioarribasaurus
>(Ghost Ranch specimens) are really two completely different dinosaurs!  

Not COMPLETELY different, but different enough to warrant generic separation.
They're still both small ceratosaurians.

>I don't know what the original Coelophysis looked like -- if anyone knows
>where I can find a photo of it please tell me.

Hunt & Lucas, in their 1991 article naming _Rioarribasaurus_ in
_Palaeontologische Zeitschrift_ (don't worry; the article's in English),
figure the lectotypes from among Cope's original material.

>Does anyone know where Coelophysis and Rioarribasaurus are at now?  And,
>if they really do turn out to be two completely different dinos, lumpers
>face a problem.  Some paleontologists, and some dino-buffs like me,
>consider _Syntarsus rhodesiensis_ to be a species of the (former)
>Coelophysis (Coelophysis rhodesiensis). But if the Ghost Ranch dinos are
>now Rioarribasaurus, would lumpers have to change _Coelophysis
>rhodesiensis_ to _Rioarribasaurus rhodesiensis_?

_Syntarsus_ is, again, different enough from the Ghost Ranch theropods to
require a different species, probably a different genus. But we're talking
small theropods here, and I'm a splitter.

>So many dinosaurs, so much confusion.  (Bloody cladists!  Burn them!)

Sadly, this little fiasco cannot be blamed on the cladists. But the situation
is not really that confusing. Hunt & Lucas simply removed specimens that they
considered incorrectly referred to the genus _Coelophysis_ and created a
separate genus for them.

>Raptor RKC (Rachel Clark)