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Remember the Alamosaurus (was RE: taxonomy is not stratigraphy)
(Posted for Jon Wagner, who is currently not subscribed.)
As possibly the only person participating in this discussion to have
seen the relevant material (apart from Ken Carpenter), and almost
certainly the only one to have WORKED in the Javelina Formation, I'd
like to make a few points. Funny, it seems I have to e-mail the list
once a year to make these points, every time a new tyrannosaur paper
1) Alamosaurus certainly HAS been used as a taxonomic "wastebasket,"
but there are reasons to believe that many, if not most of the referred
specimens belong to a single clade of sauropods. Thus, not all cited
occurrences of Alamosaurus may be A. sanjuanensis, but this doesn't
mean the whole taxon is kaput. See Lehman and Coulson (2002).
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. We aren't likely to name it, though, since the material is so
3) There is no evidence from the Javelina Formation that tyrannosaurids
fed on sauropods. There are many tooth-marked bones from this unit,
none are sauropod (and sauropod bones are very common) (Lehman, pers.
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.