Ceratosauria

Ceratosaurus: A large, heavy carnivorous dinosaur up to 23 feet (7 meters) long; it had short blade-like crests over the eyes, and a short triangular nose horn; it was the largest known ceratosaur, and appeared in the late Jurassic period; some scientists believe the dinosaur was an oddball: it appeared long after the other ceratosaurs, and may not even belong to this group; in fact, some people put it with the carnosaurs.

Dilophosauridae

Dilophosaurus: Up to 20 feet (6 meters) long and fairly slender; the skull had a double crest of thin, parallel plates on its nose and forehead; it was fancifully portrayed in the movie Jurassic Park with a frill, spitting poison, and much smaller than in actuality.

Carnosauria

Allosaurus: A large predator, with fairly long and well-muscled forelimbs and huge claws; it had large legs with heavy, clawed feet, and large, narrow jaws.

Megalosaurus: The first dinosaur to be described; it was thought to be up to 30 feet (9 meters) long, but recently studies of the fragmentary remains indicate that they may actually be parts of different carnosaurs.

The Dilophosaurus is the only member species of the Dilophosauridae. It was distinctive for the double crest on its head, but the idea that it could spit poison, as portrayed in the film Jurassic Park, is a Hollywood invention (Big Stock Photo).

Coelurosauria

Megapnosaurus: For “big dead lizard,” this small and slender dinosaur measuring 10 feet (3 meters) long, and similar in form to Coelophysis, was once known as Syntarsus.

Compsognathus: A small coelurosaur that evolved during the Late Jurassic; Compsognathus longipes is the only recognized species; it was found in a limestone quarry in Solnhofen, Germany, where the first known bird, Archaeopteryx lithographica, was also discovered.

Tyrannosaurus rex: The T. rex, or “tyrant lizard,” was an extremely large carnivorous dinosaur that evolved during the Late Jurassic period; it became the dominant predator of its time, growing close to 50 feet (15 meters) long.

Ornithomimosauria

Gallimimus: An ornithomimosaur that evolved during the Late Jurassic; the Gallimimus bullatus was featured in the movie Jurassic Park, and was thought to have been one of the fastest dinosaur runners, judging from its long hind limbs.