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About All Sharks

About All Sharks


BY. SHAUN LEVY


SHARK FAMILIES: There are more then 350 know species of sharks today, which can
all be placed under 8 scientific orders that contain 30 families. They are
placed into these categories by their shared characteristics, this is called
taxonomy. The more closeley related species are placed in another family in the
order.

SQUAINIFORMES: The angel shark as they are commonly known are
characterized by their RAY like flattened bodies. This order has one family
which is called SQUATINDAE that contains about 13 species. The maximum size
that can be attained by any one of these species is 4-6 feet in length.

PRISTIOPHORIFORMES: These shark are known as the saw shark. This order has only
has one family

PHISTOPHORIFORMES which contains five species. These sharks are
easy to recongnize due to the fact that they posses an ellongated blade like
snout that is lined with sharp teeth along the edges, thus, the name saw sharks.


SQUALIFORMES: The order possesses three family which consist of about 82 species.
These sharks are characterized by their slender, cylinder-shaped bodies, long
snouts with shortened mouths.

HEXANCHIFORMES: The Hexanchiformes or cow sharks, comprise of two families.
Recognized by their six or seven pairs of gill slits, there sharks can often
be found in deep water. The frilled shark (CHLAMYDISELACHUS ANGUINEUS)
who's appearance is quite unmistakable due to it's "eel" like appearance, is
perhaps one the strangest shark that exist today.

FOSSIL RECORD: Shark fossil record is fargmentery at best. Most fossils found
so far consist of nothing but teeth in some cases a few vertebra have been
found. This is rare due to the fact that sharks have bones instead, they have
cartiladge which countrary common belief is rather solid. In the rarest of
cases complete fossil have been discovered. Scientific data shows that
following a period of great physiological changes. There was not to many
changes in the sharks...