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Re: Removing segnosaurs from Theropoda



In a message dated 95-08-29 18:33:51 EDT, jdharris@lust.isem.smu.edu (Jerry
D. Harris) writes:

>        Yes, they could...and this sort of thing happens a _lot_ in
>cladistics, only because the cladist doesn't describe _specifically_ what
>is unique about the trait they're using -- they just mention the trait
>(e.g., saying "fused metatarsals."  So what?  Artiodactyls have fused
>metatarsals, but they look different than those of, say, birds or theropods
>-- just saying "fused metatarsals" doesn't cut it, IMHO).  The cladist
>needs to delineate precisely what is unique about the feature they're using
>for it to be truly a synapomorphy.  Thus, when one just says "interdental
>plates," then I'd have to say it's a useless character because interdental
>plates exist in a variety of organisms which are clearly distantly related.
>There's nothing I hate more than scouring some cladist's list of
>synapomorphies and saying "Well, this animals also has trait 9, and this
>group also shows trait 14," because it negates the utility of what the
>cladist is saying (or, at least, trying to say).

Right on, Jerry!

G.O.