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General Fossil Shark Tooth Information
Since shark skeletons are composed of cartilage instead of bone, often the only parts of the shark to survive as fossils are teeth. Fossil shark teeth date back
hundreds of millions of years.
The most common, however, are from the Cenozoic Era ( 65 million years ago to present ).
How a Tooth Becomes A Fossil
A tooth
become a fossil when it is buried in sediment (or other material) soon after being lost from a shark's mouth. The sediment precludes oxygen and harmful bacteria from reaching the tooth and destroying it. The general
fossilisation process varies greatly depending on the exact situation.
In general it takes approximately 10,000 years for a tooth to become a true fossil.
Why Fossil Teeth Are Different Colours
The
colour of a tooth is determined solely by the colour of sediment in which it is buried while fossilising. The tooth absorbs minerals from the surrounding sediment. As the minerals replace the natural structure of the tooth, the
tooth becomes the same general colour as the sediment. Therefore, colour is not an effective indicator of the age of a tooth. The most common colour for shark teeth is a black root with a
greyish crown. Different colours are more uncommon and significantly increase the value of a tooth.
Where the Teeth are Found and How Old They Are
The majority of the teeth offered for sale are from the Miocene-Pliocene Epochs
(approximately 24.5 million to 2 million years ago). During this time period oceans sporadically covered many
parts of what is now the South Eastern United States and South Africa.
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Fossilised Fish Teeth
Similar fossils have been found in Niger which look almost
identical with these and that have been attributed to the teeth of Pycnodus sp. Pycnodus were osseous fishes (Class Osteichthyes)
in the Subclass Actinopterygia - Order Pycnodontiformes, Family Pycnodontidae.
Up to 50 cm in length and 30 cm in height and highly compressed laterally, they are supposed to have
fed on coral branches that they triturated with these peculiar teeth.
Referring to their antiquity, those found in the deposit in Niger are said to be from the Eocene epoch
( approximately 54.8 to 33.7 million
years ago ) but Pycnodus are considered by some authors to have been distributed also in the Mesozoic era (Jurasic and Cretaceous periods) 208-65 million years ago.
See these pages: www.lakeneosho.org/More2.html http://www.blackwell-synergy.com/links/doi/10.1046/j.1467-2979.2000.00015.x/abs/
Our grateful thanks, once again, for this very detailed information from our friend Alvaro
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