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Re: Therizinosaurus



In a message dated 95-09-29 12:18:16 EDT, jdharris@lust.isem.smu.edu (Jerry
D. Harris) writes:

>       When was _this_ decided?!?  I must've been asleep...  Cast my vote
>for "Therizinosauroidea;" I find the evidence for _Therizinosaurus_ being
>amongst the formerly named "Segnosauria" compelling for now, and thus the
>older terms take precedence (I know that that isn't the exact situation
>here, but...).  BTW, this isn't a matter which can be put to this sort of
>vote; if it were, don't you think _Brontosaurus_ would still be in use
>instead of _Apatosaurus_?  8-)  You just has to take them as you gets
>them...
>
>

Therizinosauroidea is a superfamily; Segnosauria is an order. The two terms
are not of equivalent rank (which doesn't matter to a cladist), so both names
can exist, with Segnosauria including Therizinosauroidea as a subgroup. But
inasmuch as only one superfamily is presently known in Segnosauria, it is a
redundant subdivision. Here's how I would do it:

Phytodinosauria
  Sauropodomorpha
    Brontosauria
      Sauropoda
      Prosauropoda
    Segnosauria
        Alxasauridae
        Segnosauridae
        Therizinosauridae
etc.

Some may want to combine the three families in various ways. If so,
Therizinosauridae has priority over all the others at all family-level ranks.

G.O.