Geoscience Reference
In-Depth Information
ally good material in which to find fossils because delicate struc-
tures are often preserved, such as fine hairs on the insect's body and
the pattern of veins in the wings. These soft tissues are not commonly
preserved in fossils buried in sandstone or mudstone. The excep-
tionally complete fossilization of insects in amber provides scientists
with many extraordinary clues to identify ancient insects and to ana-
lyze where their groups fit on the evolutionary tree.
In fact, however, no Mesozoic insects in amber have ever been
found with blood inside them, and most insects in amber lived much
later than the dinosaurs seen in the movie
Jurassic Park.
As men-
tioned earlier, dinosaurs originated in the Triassic period. The earliest-
known dinosaurs, such as the small carnivores
Herrerasaurus
and
Eoraptor
from Argentina, lived about 230 million years ago. Unfor-
tunately, we have never found amber with insects inside from rocks
that are this old. The next period during the Age of Dinosaurs was
the Jurassic, when the first giant, plant-eating sauropods, such as
Bra-
chiosaurus,
lived, as well as fierce carnivores such as
Allosaurus.
But
no Jurassic amber with biting insects inside has ever been discovered.
So despite the name of the topic and the movie, there is not even any
insect-bearing amber available to use in trying to clone dinosaurs
from the Jurassic period.
There are, however, some biting insects preserved in Cretaceous
amber. This was the age in which
Tyrannosaurus, Velociraptor, Tricer-
atops,
and
Ornithomimus
lived, as well as the sauropods from Auca
Mahuevo. A few small biting insects called midges are known from
amber this old, but none have been found with blood in them, and
none of these have been found at Auca Mahuevo. At present, the old-
est known biting insect preserved in amber is about 125 million years
old. It is possible that paleontologists will eventually find Triassic,
Jurassic, and Cretaceous insects with blood inside them, but it would
be rare and, based on experience, unlikely.
One reason for this improbability is that blood breaks down quickly
after an animal dies. Rotting actually begins within minutes after
death, which is why bodies must be embalmed if a person is to be
buried and is also why blood that is donated for operations must be
maintained under strict temperature controls. So even if a blood-
filled insect were to be discovered in amber, the blood would have had
to have been perfectly preserved in amber for more than 65 million
