The first of the horned dinosaurs was little Protoceratops (prot-o-SER-at-ops). Even though his name means the "first horned face" he didn't have any horns. Much later, relatives of Protoceratops developed horns on their faces. Protoceratops had a curved horny beak, which was probably used in biting off the stems of plants. A bony frill extended backward over his neck, and the lower jaw muscles were attached to this frill. Protoceratops was about five or six feet long. He walked on four legs, and he had a long, slender tail that was flattened at the sides.
For a long time paleontologists had suspected that dinosaurs laid eggs. This idea was based on the fact that most reptiles of today lay eggs. But the paleontologists had never been able to find any fossil dinosaur-eggs.
Then quite unexpectedly an expedition in 1928 found several nests of dinosaur eggs in the Gobi Desert and, near the nests, a number of skeletons of Protoceratops. Back in the United States, museum scientists sawed open two of these eggs with a special saw and inside they found the tiny skeletons of Protoceratops. These fossil eggs had a pebbly surface and were from four to five inches long. One end was larger than the other, somewhat like the lizard eggs of today. So it has been proved that at least one kind of dinosaur did lay eggs. Probably all dinosaurs were egg-layers.
Triceratops (try-SER-at-ops), another of the horned dinosaurs, was much larger than little Protoceratops. He was about twenty feet long and stood eight feet high. He may have weighed as much as six or seven tons. His head was protected by a tremendously large bony frill that extended back over his neck and shoulders. He also had a curved beak and, as his name tells us, three horns. Two of the horns were very long and sharp, but the one over his nose was much smaller. These horns must have been powerful weapons that he used in fights with Tyrannosaurus. Triceratops was probably able to lower his head and make running thrusts with his horns.
The horned dinosaurs may have used their horns in battles with one another for mates as well as for protection from the meat-eating dinosaurs. The arrangement and number of horns varied greatly among the horned dinosaurs. Monoclonius had a single great horn on his nose and a very small horn above each eye, but Styracosaurus had a large horn on his nose and spikes all around the outer edge of his neck frill. We know that all the horned dinosaurs were plant-eaters.
Some scientists believe that Protoceratops and Triceratops did not live at the same time, because of how these creatures have been preserved under sediment. Protoceratops was the first of the horned dinosaurs, and millions and millions of years later Triceratops, the last of the great horned dinosaurs, developed.
No comments:
Post a Comment
Thanks for your thoughts. All comments are moderated. Spam is not published. Have a good day!