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Re: Kritosaurus?



David Krentz wrote:

>Has there been any recent conclusions as to the relationship of 
>Kritosaurus and Gryposaurus?  
        Ahhhh... my babies... I will be addressing this question in print in
the (hopefully) not-too-distant future. However, the long and short of it is
that I agree with Horner that species navajovius and notabilis are both
valid. As to what genera you wish to place them in, that is largely a
question of phylogeny and/or arbitrary gradistic evaluation. I will not
comment on this, except to say that...

>Are they indeed different species or are they 
>the same thing?
        They are almost certainly different species, although they seem to
approach each other morphologically. A specimen from the Bearpaw Shale is
probably notabilis, but has a very prominant, navajovius-like hump, so much
so that Horner has referred it to the latter species. I hope to see it soon.

George wrote:
>Kritosaurus is a nomen dubium because the type specimen of the type species 
>K. navajovius (posterior portion of skull) is too poorly preserved to
        A) I detest this aspect of the ICZN code... further work has turned
up two new skulls of this taxon, and we should continue to honor the
original appelation, rather than employing taxonomic legalism in the most
obfuscatory manner possible, as has already been done.
        B) Perhaps it is not "diagnostic" because no one has bothered to
look beyond the nasals for autapomorphies. They may be there, you never know...
        [don't bother, I'm already looking...]
 
>distinguish the genus from Hadrosaurus,
        Rather difficult, wouldn't you say, considering the limited
documention of skull material in that genus?

>Gryposaurus,
        If you regard them as congeners, this isn't really a problem... hard
to distinguish someone from themselves, no?

>Anasazisaurus, and Naashoibitosaurus.
        ... are without a single doubt specimens of K. navajovius, see
Horner 1993.

>Barring complications, use the name Gryposaurus for the 
>familiar big-nosed hadrosaur species of the northwestern US, and 
>Anasazisaurus or Naashoibitosaurus for the big-nosed hadrosaur species of the 
>southwestern US.
        Sez you. Personally, I don't care if you decide the San Juan species
is different enough to warrant a separate genus (although that would be an
almost unbelievably fine hair to split), but let's not try to complicate the
situation further... there is NO evidence for more than one hadrosaurine
species in the (non-Naashoibito Member) Kirtland Shale. And
"Naashoibitosaurus" is not from the Naashoibito Member (see recent Willams
papers). Barring complications, let's eshew obfuscation and call it
Kritosaurus navajovius, a very old and well-established name with a long
history and much coverage in the literature. Leave your rulebooks at home
kids, come play science!

        Later,

        Wagner
--------------------------------------------------------------------------------
     Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
  "Why do I sense we've picked up another pathetic lifeform?" - Obi-Wan Kenobi