Geoscience Reference
In-Depth Information
merits were from small vertebrae a few inches long, though none of
them knew what kind of animal the fragments came from. Nonethe-
less, our geologists were excited because Auca Mahuevo, although rich
in dinosaur eggs and embryos, had not yet yielded any skeletons of
adult dinosaurs. Perhaps that would now change.
After putting a number of the larger chunks in a plastic bag, the
crew drove back to the quarry. A large tarp had been strung between
two of the vehicles to provide a bit of shade from the withering
noonday sun. As we all began to eat, the bag of fossil fragments cir-
culated among the paleontologists to see if anyone could identify the
fragments. Immediately, Luis and Rodolfo became intrigued, and
after a few moments of close inspection, they agreed on several basic
points. First, the fragments represented tail vertebrae of a dinosaur.
Second, the tail vertebrae did not seem to belong to a sauropod, but
instead came from either a meat-eating theropod or a plant-eating
ornithischian. This point was particularly exciting because with all
the eggs of sauropods that we had found, it seemed most likely that
any skeletal remains discovered would also be from sauropods. Third,
we should examine the site more closely to see if more of the skeleton
lay buried beneath the surface.
The next day, Luis, Rodolfo, and the geological team examined the
remaining vertebrae fragments on the surface. Then we began clear-
ing away the loose dirt around some of the larger fragments with a
paintbrush to see if more bones lay buried under the surface. Within
a few hours, our efforts had paid off. One by one, four more tail ver-
tebrae slowly appeared. A tone of elation and anticipation permeated
our conversation, but there was also some trepidation as it became
clear that we would face a massive excavation effort if the whole
skeleton lay beneath the dirt.
We were certain that, as new bones were exposed, we were pro-
gressing from the back of the tail toward the front. We could all see
that these new tail vertebrae were arranged in a line that pointed into
the small ridge on which we were working, and that each new one that
we uncovered was larger than the previous one, as we followed the tail
into the hill. At this point, we were sure that whatever remained of the
skeleton was leading into the small hill that it sat on. In terms of
preservation, this was excellent news: perhaps only the end of the tail
had weathered away before Alberto had found the skeleton. But to find
