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Ojo Alamo Sandstone hadrosaurs
James E. Fassett, S.G. Lucas, R.A. Zielinski, J.R.
Budahn, 2000. Compelling new evidence for Paleocene
dinosaurs in the Ojo Alamo Sandstone, San Juan Basin,
New Mexico and Colorado, USA. Lunar & Planetary
Institute Contribution # 1053:45-46
James E. Fassett & S.G. Lucas, 2000. Evidence for
Paleocene dinosaurs in the Ajo Alamo Sandstone, San
Juan Basin, New Mexico. New Mexico Museum of Natural
History & Science Bulletin 17:221-230
The history of the area:
James E. Fassett, 1973. The saga of the Ojo Alamo
Sandstone; or the rock-stratigrapher and the
paleontologist should be friends. Four Corner
Geological Society Memoir, pp. 123-130
The 2000 paper, like James Fassett's reiteration in
the Geological Society of America volume, illustrates
the hadrosaur right femur, now on display at the
Geology Museum of the University of New Mexico.
There are other disarticulated specimens -- Gilmore in
1919 reported that Reeside had found theropod
vertebrae in the area -- but I have yet to see a
detailed, annotated list of these. The femur, indeed,
is from the Paleocene, but so many questions are not
answered, in particular: where/how did these isolated
dinosaur populations survive the K/T events? It could
be, e.g., that the right femur is from a hadrosaur
born after the K/T events. That their existence may
have been nightmarish in unimaginably environmentally
stressed regions is cause for further explorations in
the areas involved.
The flying theropods were radiating, some lineages
dying out, some surviving, but the larger taxa -- the
hadrosaurs are known only from this right femur, but
surely others, perhaps ceratopsians, were alive --
were in decimated gene pool landscapes.
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