A2.37 Triceratops horridus (three-horned face) / Traits:
  • Cells have DNA
  • Cells have a nucleus in them
  • Cells have mitochondria
  • Multicellular
  • Cells are held together with collagen.
    Sexual reproduction
  • Early embryo forms as a hollow ball of cells called a blastula
  • This blastula opens into a tube “tail end first”
  • Has a head and is bilaterally symmetrical (you can draw one line down the middle)
  • Cells organize themselves into true tissues (muscle, nerves)
  • Cells organize themselves into true organs (heart, liver, stomach)
  • Has a hollow space between the gut and outer body wall where organs are (this space is called a coelem—pronounced “see-lome”
  • Segmented body
  • Internal bony skeleton
  • Backbone, Spinal chord and braincase
  • Had jaws
    Enamel teeth
  • Had lungs
  • Had paired appendages
  • Had four legs
  • Amniotic egg (able to lay its eggs out of water)
  • Two openings in the roof of the mouth (“palatal openings”)
  • Two openings in the side of the skull at the temple (“diapsid openings”)
  • Opening in the skull in front of eye socket (“antorbital fenestra”)
  • Has a hole in the hip socket allowing it to stand upright
  • Has a backward pointing pubis bone
  • Narrowing of the middle ear bone—only one middle ear bone (“slender stapes”)
    A notch in the two bone just behind the eye opening (“notch in postorbital”)
    Simple hinge-like ankle (requiring a more erect posture—no sprawling walk)
    Cheeks: Inset teeth rows
  • Bony shelf over back of skull
  • Beak-like bone on end of nose (“rostral bone”)
    Long frill on back of the skull
  • Nose and brow horns
  • Two horns above the eyes and one on the nose

ANATOMY
Triceratops was a rhinoceros-like dinosaur. It walked on four sturdy legs and had three horns on its face along with a large bony plate projecting from the back of its skull (a frill). One short horn above its parrot-like beak and two longer horns (over 3 feet or 1 m long) above its eyes probably provided protection from predators. The horns were possibly used in mating rivalry and rituals. It had a large skull, up to 10 feet (3 m) long, one of the largest skulls of any land animal ever discovered. Its head was nearly one-third as long as its body. Triceratops hatched from eggs.
Triceratops was about 30 feet long (9 m), 10 feet tall (3 m), and weighed up to 6-12 tons. It had a short, pointed tail, a bulky body, column-like legs with hoof-like claws, and a bony neck frill rimmed with bony bumps. It had a parrot-like beak, many cheek teeth, and powerful jaws.

WHEN TRICERATOPS LIVED
Triceratops lived in the late Cretaceous period, about 72 to 65 million years ago, toward the end of the Mesozoic, the Age of Reptiles. It was among the last of the dinosaur species to evolve before the Cretaceous-Tertiary extinction 65 million years ago. Among the contemporaries of Triceratops were Tyrannosaurus rex (which probably preyed upon Triceratops), Ankylosaurus (an armored herbivore), Corythosaurus (a crested dinosaur), and Dryptosaurus (a meat-eating dinosaur).
BEHAVIOR
Triceratops was probably a herding animal, like the other Ceratopsians. This hypothesis is supported by the finding of bone beds, large deposits of bones of the same species in an area.
When threatened by predators, Triceratops probably charged into its enemy like the modern-day rhinoceros does. This was probably a very effective defense.
REPRODUCTION
No one knows how Triceratops reproduced or raised their young, except that they probably hatched from eggs.
INTELLIGENCE
Triceratops was a ceratopsian, whose intelligence (as measured by its relative brain to body weight, or EQ) was intermediate among the dinosaurs.


DIET, TEETH, AND ITS POSITION IN THE FOOD CHAIN
Triceratops was an herbivore, a plant eater (a primary consumer). It probably ate cycads and other low-lying plants with its tough beak. Triceratops could chew well with its cheek teeth (like other Ceratopsians, but unlike most other dinosaurs).
Triceratops was hunted and eaten by T. rex. Coprolite (fossilized feces) from a T. rex was recently found in Saskatchewan, Canada by a team led by Karen Chin. This 65 million year old specimen contains chunks of bones from an herbivorous (plant-eating) dinosaur which was eaten by the T. rex. This bone fragment is perhaps part of the head frill of aTriceratops.
LOCOMOTION
Triceratops walked on four short legs; it was a relatively slow dinosaur. Dinosaur speeds are estimated using their morphology (characteristics like leg length and estimated body mass) and fossilized trackways.
LOCATIONS AND DISCOVERY OF FOSSILS
Many Triceratops fossils have been found, mostly in western Canada and the western United States. Paleontologist Othniel Marsh named Triceratops in 1889 - from a fossil found near Denver, Colorado, USA. At first this fossil was mistakenly identified as an extinct species of buffalo. The first Triceratops skull was found in 1888 by John Bell Hatcher. About about 50 Triceratops skulls and some partial skeletons have been found.
3/16/08