|
|
|
Dinosaur Classification |
Between 1818
and 1840, fossils of large prehistoric reptiles were
found. In 1824, William Buckland described what he called
a Magalosaurus. This was followed by other finds
including the Iguanodon. Hylaeosaurus, Thecodontosaurus and
Paleosaurus. Naturalist Richard Owen carefully studied
many of these fossils and in 1841, he wrote a report on them for
the British Association for the Advancement of
Science. In it, he grouped all of them together in a
classifications that he called Dinosauria. It comes from
the Greek words deinos meaning "terrible,"
and sauros, meaning lizard. It was the first
known use of the word. Although the term
"Dinosauria" is commonly used to identify the ancient
reptiles, it is not a valid taxonomic category.
Dinosaurs have traditionally been
placed in the reptilian subclass Diapsida, which are reptiles
with pairs of temporal openings in the skull. As such,
they are grouped with the crocodilians, thecodonts and
pterosaurs, all of which have socketed teeth and a number of
other similar features. These are often called the
archosaurian reptiles.
During recent years our knowledge of
dinosaurs has expanded greatly. There are now more than
550 generic names and at least 1,000 described species. It
is widely believed that not all are valid, because of incomplete
specimens, misidentification, and duplication. However the
great interest in these extinct reptiles has led to a movement
to place them all in their own distinct class, comparable to
mammals and birds. But that idea has not yet been
universally accepted. |
|
Basic
Classification |
Biological
classification is based on anatomical differences.
Dinosaurs have two distinctly different types of hips.
These led to them being assigned to one of two
orders:
Order - Saurischia - the reptile- hipped dinosaurs.
Order - Ornithischia - the bird-hipped
dinosaurs. |
|
The
Saurischia |
| These are
the reptile-hipped dinosaurs. The Prosauropods and
Sauropods were herbivorous (they ate plants) and the Theropods
were carnivorous (they ate meat) |
|
Contains |
Infraorder
Prosauropoda |
Primitive
forerunners of the Sauropods. Smaller than their
descendents. |
|
Family
Anchisauridae. Primitive prosauropods
that include Anchisaurus and Plateosaurus.
Family Melanorosauridae.
Advanced prosauropods such as Melanorosaurus and
Riojasaurus. |
Infraorder
Sauropoda |
Large
herbivorous quadrupeds. Most famous is the Brachiosaurus |
|
Family
Cetiosauridae. Primitive and poorly
studied sauropods such as Cetiosaurus.
Family Diplodocidae.
More advanced and better known large sauropods.
Best known are Diplodocus and Apatosaurus
(Brontosaurus).
Family Brachiosauridae.
Largest of all the sauropods. They had greatly
elongated and necks. Brachiosaurus is the most
famous.
Family Titanosauridae.
Advanced sauropods, primarily from the southern
continents. Example are Titanosaurus and
Alamosaurus.
Family Camarasauridae.
Modern size sauropods with relatively short necks and
tails for this Infraorder. Include Carnarasaurus
and Morosaurus.
|
Suborder
Staurikosauria |
|
Suborder
Theropoda |
All the
carnivores, except for the staurikosaurs. Always
traveled on their hind legs. |
|
|
|
