Archaeopteryx lithographica
- Compsognathus longipes (fossil shown below) was a small
dinosaur about
the size of a chicken. It had delicate, long hind limbs and a foot and
ankle joint that would suggest that it walked or hopped in an erect or
semi-erect position like a bird. It had a long neck, a slight head, and
small anterior limbs.
Compsognathus longipes
- Deinonychus antirrhopus (sketch shown below) was a relatively
small (about 1.5m high and 2.5m end to end, including tail) and agile
dinosaur. Its two front limbs were such that they could not have
supported the animal's weight so Deinonychus was most likely
biped, as are birds. The foot of the dinosaur allows it to visciously grip
and tear its prey. These traits suggest that the small dinosaur very
active and very agile and therefore had a high metabolism. Animals with a
high metabolism produce enough energy, or heat, to maintain a stable body
temperature, otherwise known as being warm-blooded.
Deinonychus antirrhopus
- Velociraptor, a Maniraptorin dinosaur, had a half moon-shaped
(semilunate) wrist, as do modern birds, a fused clavicle, a backwards
pointing pubic bune, and reduced fourth and fifth digits.
- Skeletons of Oviraptor (a Cretaceous therapod) have been found
sprawled out across nests, as if they were protecting the eggs, a trait
which is seen in birds. The eggs of the Oviraptor bear
structural similarities to birds' eggs.
- Sinosauropteryx is a small, turkey-sized dinosaur with
fringed, filiamentous structures on its back bone. These structures may
have been what gave rise to feathers.
- Protarchaeopteryx appears to have short feathers covering its body and long feathers attached to the tail.
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