Geoscience Reference
In-Depth Information
these gigantic dinosaurs had given birth to live young rather than hav-
ing offspring that hatched from eggs. The ultimate clue needed to
identify what dinosaur had laid these Patagonian eggs was still miss-
ing. We gathered excitedly to assess our initial discovery, and Luis
issued his challenge for someone to find an embryo before we once
again fanned out across the flats and ridges.
Fossils of embryos rank among the rarest of dinosaur remains
because they represent the fragile skeletons of baby dinosaurs that
have not yet hatched out of the egg. The skeleton of a growing
embryo is only partially made of bone. Much of it is still composed of
softer cartilage. This cartilage is rarely fossilized because it often
decays along with the skin, muscles, and organs soon after the embryo
dies. Consequently, such small, delicate skeletons are hardly ever
preserved. They either decay or get destroyed before they become fos-
silized. Yet, this huge treasure of fossil eggs was also encouraging
because we suspected that a few of them could easily have embryonic
bones preserved inside.
A half hour later, Carl Mehling approached us excitedly. Carl was
one of our designated fossil collectors from the American Museum of
Natural History. A passionate collector, his enthusiasm and acute
sense of humor were infectious, and he often instigated hilarious dia-
logues that made him the life of the party, but at this moment his
face reflected a measure of ecstatic anticipation. He had found an egg
with a small, rocky sheet of bumpy, mineralized material preserved
inside, and he thought the texture preserved on the surface resem-
bled dinosaur skin. At first, Luis was skeptical. The patch of textured
rock was small and might just have been some unusual mineral crys-
tals. Besides, fossils of dinosaur skin and other types of soft tissue are
extremely rare, and no one had ever discovered fossils of embryonic
dinosaur skin inside an egg. To make a positive identification, we
would have to keep searching for more.
By the end of the day, we were exhausted but elated. We knew we
had discovered a remarkable new fossil site, even though we had not
found any more patches of possible skin and were not sure exactly
what kind of dinosaur eggs we had found. Now, it was time to cele-
brate.
Next morning when we returned to the site, most of the crew
continued looking for more fossils of the potential embryonic skin and
