Rob Gay <rob_redwing@hotmail.com> wrote:
>If Alamosaurus was of Asian origin, why there has not been found yet an
>Asian Alamosaurus? Or even a Canadian Alamosaurus?<
This is true that _Alamosaurus_ seems to be limited in its distribution to
the southern portion of North America. Specifically, in Utah (Wasatch
Plateau), New Mexico (San Juan Basin), and Texas (Big Bend area). Beyond
_Alamosaurus_, these three areas seem to have more in common with each other
than they do with more well known Masstrictian faunas of northern NA
(Particularly Utah and Texas, New Mexico to a somewhat lesser degree). This
may suggest a possible barrier between North and South NA during late K
times, across which titanosaurs could not move (just a suggestion, nothing
more). But if this barrier was real, than this would have limited
titanosaurs to northern NA during the late K, and they would not be present
in the southern basins. This seems to suggest to me that at least
_Alamos! ! ! aurus_ had ties to SA.Perhaps the migration route used by Alamosaurus leaving Asia was more upland, and thus we don't have a record of them in Canada or Northern US because they lived in habitats that did not cater well to fossils being left behind. IIRC, I seem to remember reading of a group of lizards that also lived in the southwest at that time that had more in common with lizards from Central Asia than the rest of North America. I suspect the only reason we don't have sauropods in Canada, ect. is because of enviromental and habitat differences.
Peace,
Rob
Student of Geology
Northern Arizona University
Biological Science Tech
Manti-La Sal National Forest
AIM: TarryAGoat
http://www.geocities.com/elvisimposter/dinopics.html
http://www.cafepress.com/RobsDinos
"A _Coelophysis_ with feathers?"
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