Re: Coelophysis 18, Rioarribasaurus 8

[Stan Friesen <swf@ElSegundoCA.NCR.COM>]

From: "King, Norm" <nking.ucs@smtp.usi.edu>

 > I think that _Marasuchus_ is also an inappropriate name.  Since 
 > subsequent studies have shown that the type material for _Lagosuchus_ is 
 > non-diagnostic,

Except that the type material for Lagosuchus is NOT non-diagnostic.
It is merely lacking any autapomorphies - which is a perfectly reasonable
thing to see in an ancestral species. (In fact some strict cladists
wish to use this as the main criterion for *recognizing* ancestral
species).

The Marasuchus material has some apomorphies that are demonstrably
*absent* in the Lagosuchus material.  The two type specimens thus
almost certainly belong to distinct species.

 >  But now, when someone uses the name _Lagosuchus_, we need to ask
 > whether he/she means the "old, original" _Lagosuchus_, or really
 > means _Marasuchus_.

Or both.

THe problem is that whether the two species should belong to one genus
is a judgement issue, unless one is a strict cladist.

They certainly deserve distinct names at the species level, and a strict
cladist *must* give them distinct genus level names.

swf@elsegundoca.ncr.com         sarima@ix.netcom.com

The peace of God be with you.