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Re: Why did small dinos become extinct?
On Fri, 23 Nov 2007, David Marjanovic wrote:
We now know of burrowing dinos (Oryctodromeus and possibly Orodromeus).
Admittedly Oryctodromeus was vegetarian and Orodromeus was a close
relative, so both were doomed under the standard explanation. But why were
there no burrowing small predatory dinos in the latest Cretaceous or, if
there were, why did they perish?
As far as we currently know, there were no burrowing predatory dinosaurs
Paleontologists have unearthed an ancient, sediment-filled burrow that
holds remains of the creatures that dug it. The find is the first
indisputable evidence that some dinosaurs maintained an underground
lifestyle for at least part of their lives.
While scouring 95-million-year-old strata in southwestern Montana,
paleontologist David J. Varricchio of Montana State University in Bozeman
and his colleagues stumbled upon an unusual patch of sandstone protruding
from the rock that surrounded it. Soon after they began to excavate the
sandstone, they found a compact mass of small bones. After teasing apart
the tangle, they discovered that the remains represented an adult and two
juvenile dinosaurs of a completely new species.
"All the pieces are there" to support the burrowing interpretation, says
Paul Sereno, a paleontologist at the University of Chicago.