Re: Remember the Alamosaurus (was RE: taxonomy is not stratigraphy)

[Tim Donovan <uwrk2@yahoo.com>]

> 2) The "Javelina tyrannosaur" is either a)
> indeterminate (i.e., cannot 
> be called T. rex), or b) a new species and
> definitely not T-rex. Ron 
> Tykoski and I are working (long term) on a
> redescription of the maxilla 
> of this animal; whether or not it is a new taxon
> depends a bit on the 
> patterns of variation in tyrannosaurids (believe it
> or not, the 
> variation in question has not yet been documented
> fully, despite Carr's 
> impressive body of work). Oddly enough, when viewed
> in life position 
> (Lawson illustrates it laid flat), this maxilla is
> not as short as it 
> first appears, and the animal was probably within
> the range in snout 
> shape seen in T. rex. It is not at all clear whether
> the maxilla is 
>  from an adult, so claims that it is an undersized
> tyrannosaurid are 
> premature (it is larger than "Nannotyrannus," based
> on published 
> illustrations)
> I believe we will be able to say it
> is indeed a new 
> species, and, given its apparent phylogenetic
> position, possibly a new 
> genus. 

  That makes sense. IIRC TMM 41436-1 was found low in
the Javelina, and therefore at least 69 Ma old, well
before the Lancian.





>We aren't likely to name it, though, since
> the material is so 
> fragmentary.
> 
> 3) There is no evidence from the Javelina Formation
> that tyrannosaurids 
> fed on sauropods.


  Considering the small size of the specimen compared
to T. rex, that isn't surprising. Alamosaurus was too
big to overcome, except for juveniles. Maybe that was
why Alamosaurus was so common in the Javelina but not
in the units where T. rex apparently is known, the
McRae and North Horn.


> There are many tooth-marked bones
> from this unit, 
> none are sauropod (and sauropod bones are very
> common) (Lehman, pers. 
> com., 2005).
> 
> 4) One abstract with one date from the MIDDLE of a
> unit must NOT be 
> used to date an entire formation. The Javelina
> grades into the 
> overlying Black Peaks Formation, and the K/T
> boundary "wobbles" between 
> these two units. There is no evidence that I know of
> for a hiatus 
> between the two units, nor a hiatus at the boundary.
> In fact, the K/T 
> boundary IS preserved in some sections. I have eaten
> lunch on it. 
> Additional radiometric data have not yet been
> released. Without 
> spoiling the "surprise," I'll just say that I have
> every confidence 
> that the Javelina is, at least in part,
> contemporaneous with the Lance, 
> given what is currently known.
> 
> 5) To respond to something Denver Fowler wrote:
> >Lehman got his stratigraphy
> >confused (see various works by Sullivan et al);
> 
> Denver, with all due respect, I think you ought to
> pick your 
> stratigraphers a little more carefully. If you get
> out in the field and 
> try to reproduce results, I believe you will find
> that you are backing 
> the wrong horse. Recall that "Sullivan et al."
> includes the folks who 
> named Naashoibitosaurus, which isn't even from the
> Naashoibito. Lehman 
> informed me of this years before it hit the press,
> because he 
> REMEMBERED, off the cuff, where that site is. You
> have every right to 
> follow whatever authority you see fit, but I
> respectfully recommend you 
> do so based on something other than the date of
> publication.
> 
> If you wish to reply to this message, please reply
> to me as well, as I 
> am not on the list, and be prepared to forward my
> replies as well.
> 
> Thanks!
> 
> Jon
> 


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