Geoscience Reference
In-Depth Information
CHAPTER
SIX
Finding Evidence in the Eggs
at Our Forensic Labs
Dinosaur Embryos and Embryonic Skin—
the Rarest of All Dinosaur Fossils
Adult skeletons of dinosaurs are not that uncommon because their
massive bones and durable enamel teeth stand a reasonable chance of
becoming fossilized. Finding the fragile bones and skin of unhatched
dinosaurs is much more rare, however, because their poorly calcified
bones and delicate skin decompose rapidly after the embryo dies. At
the time of our discovery, in fact, fossilized embryos were known from
only a handful of different dinosaur species, despite hundreds of
species having been discovered. The embryos of three kinds of meat-
eating dinosaurs had been excavated from Cretaceous rocks of Mon-
golia, China, and Montana, including specimens of an oviraptorid, a
therizinosaurid, and a troodontid, respectively. Less complete
embryos of an unidentified species of meat-eating dinosaur had been
collected from late Jurassic rocks of Portugal, and embryos from one
kind of plant-eating duckbill,
Hypacrosaurus,
were known from Mon-
tana. But absolutely no fossils of embryonic dinosaur skin had ever
been discovered before 1997. This poor representation of embryonic
dinosaur remains explains why we were anxious to get our eggs pre-
pared and see what was inside.
Fossil preparators are essential in any paleontological team. Even
with the advent of modern techniques such as CAT scans, which allow
paleontologists to peer inside fossil bones and skulls without manually
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