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'''Shark teeth''' are relics of shark evolution and biology. Shark skeletons are composed entirely of cartilage. Often the only parts of the shark to survive as fossils are teeth. Fossil shark teeth have been dated back hundreds of millions of years. The most ancient types of sharks date back to 450 million years ago, and they are mostly known from their fossilized teeth. The most common, however, are from the Cenozoic Era (65 million years ago).
The teeth of sharks are not attached to the jaw, but embedded in the flesh, and in many species are constantly replaced throughout the shark's life. All sharks have multiple rows of teeth along the edges of their upper and lower jaws. New teeth grow continuously in a groove just inside the mouth and move forward from inside the mouth on a "conveyor belt" formed by the skin in which they are anchored. In some sharks rows of teeth are replaced every 8–10 days, while in other species they could last several months. The lower teeth are primarily used for holding prey, while the upper ones are used for cutting into it. The teeth range from thin, needle-like teeth for gripping fish to large, flat teeth adapted for crushing shellfish.

Contents

Overview

Anatomy of A Tooth

Fossil Teeth

Megalodon Teeth

Transitional teeth

Great White/Mako Transitional Teeth

Collecting Shark teeth

Field Collecting

On-line Auctions

Identification

Displaying the Collection

Trivia

Collections Housed in Riker Displays

See Also

References

External Links

Overview

A shark can have hundreds of teeth in its jaw. Sharks, as well as other Chondrichthyes, have the ability to replace their teeth if they become damaged during feeding or fall out due to natural causes. Many icthyologists have suggested that sharks can lose tens of thousands of teeth within the span of a few years.

Anatomy of A Tooth

Fossil Teeth

Megalodon Teeth

Carcharocles megalodon, is one of the most sought after type of shark tooth in the world. these teeth are in extremely high demand by collectors and private investors, and its teeth can fetch steep prices. It lived during the Miocene and Pliocene eras, roughly 18-1.2 million years ago. Its teeth averaged 1 1/2 - 5 1/2 inches, with the largest teeth reaching sizes of 7 inches or more in length. Based on the size of their teeth, ''Carcharocles megalodon'' may have reached sizes of about 50 feet in length, rivaling the size of the largest fish alive in the world today, the Whale shark.
Large numbers of ''megalodon'' teeth have been discovered across both coasts of the United States. The most plentiful location within the U.S. is in Venice, Florida.
However, these large and magnificent sharks disappeared relatively close to the rise of modern man. However, there have been many unconfirmed reports of large animals resembling large, carnivorous, sharks.
Megalodon teeth have been discovered that some argue date as recently as 10,000 to 15,000 years ago. This claim is based on the discovery of two teeth by the HMS Challenger scientific expedition (these teeth were dated by estimating the amount of time it took for manganese to accumulate on them, although it is quite possible the teeth were fossilized before being encrusted).

Transitional teeth

Identifying shark teeth is tedious work, especially with all of the damaged, worn, and different teeth. It is even more difficult because of the so-called "In-Between Teeth". These are teeth that are from a shark species that was evolving into another, different species. An example of this can be seen with ''Carcharocles auriculatus'' teeth that were in the state of evolving into ''Carcharocles angustidens''. These are teeth that are no longer ''auriculatus'', but not yet ''angustidens'' either.

Great White/Mako Transitional Teeth

The most common and most referred to transitional shark teeth are the ones coming from what is believed by some to be an unusual form of great white shark. Great white shark transitional teeth are often characterized for their wide crowns. These teeth can also be identified by the way the serrations fade, being more pronounced near the root, and disappearing close to the tip of the tooth.
Many paleontologists now believe that these transitional teeth represent the evolutionary path between Isurus hastilis(Broad-toothed Mako)and the Great white shark. The evolutionary history of the great white shark and its relation to megalodon are hotly debated.
Because of their transitional state, these teeth are rare. These teeth are prized by collectors, hobbyists, and museums.

Collecting Shark teeth

To date, there are hundreds of thousands of people who take pride in collecting shark teeth, from small children competing on who found the biggest one, to serious amateur fossil hunters, whose collections rival even those of many museums worldwide.

Field Collecting

Of the many ways to collect shark teeth, the most common, and most exciting way is to collect in the field.
In order to accurately collect shark teeth, you must start to excavate in land that others have already started digging in. Examples of these include river bed banks, sand pits, and beaches. The next step involves learning how to find the teeth. The most common and simplest way is to walk along the site and collect. Many people prefer to use a shovel and sieve. Many collectors use fork-like garden tools to excavate sand.
Many sites provide hard, solid teeth, that are only washed and dried. these teeth are typically worn, because they were frequently moved and redeposited in different areas repeatedly before settling down. Other locations, however, yield perfect teeth that were hardly moved during the ages. these teeth are typically fragile, and great care should be taken while excavating them.

On-line Auctions

There is a small, but established shark tooth trade, and it is up to the collector if he/she wants to 'complete' their collection by buying a few fossils.
Many high quality fossils can be found online, and many are often affordable. As well as on the internet, shark teeth may be procured from Rock and Mineral shows, such as the annual Tucson Gem & Mineral Show, and other, smaller, rock shops.
The prices of shark teeth depend upon the overall quality of the tooth. There is no definite price for a shark tooth, as the market is based on supply-and-demand. Another way of obtaining shark teeth is to "swap" finds with others at rock shops of mineral shows/conventions.

Identification

The most often method of shark tooth identification, is to procure a book on sharks teeth and attempt to identify it yourself. Many expert collectors tend to identify their teeth this way, yet others prefer to seek experts willing to help them identify their teeth.
Many identified shark teeth are transitional species. Because sharks lose tens of thousands of teeth in their lifetime, their teeth vary greatly, because they are constantly evolving new changes in their feeding style, and their teeth.

Displaying the Collection

As you collect shark teeth, your collection will expand exponentially. Many people find suitable housing containers as small individual zip lock bags, and empty jewelry boxes. Many high quality display cases are made especially for collectibles, such as shark teeth. These are most often known as Riker Displays. They are made from high quality black chipboard, with either a cotton or synthetic fiber cushioning the teeth.
It will often be necessary to catalog your collection. A very popular method is writing a number on the back of the tooth in waterproof India Ink. Many other collectors prefer to include display cards within the display cases in order to save time and effort in trying to re-identify the same species again. These display cards usually include the common name, the scientific name, the approximate age of the tooth, and when and where the tooth was collected.

Trivia

★ Lemon sharks have the ability to replace damaged or lost teeth every eight days.

★ Whale Sharks have thousands of miniature teeth within their jaws. These teeth are vestigial, as they serve no purpose to the Whale shark, as it is a filter feeder.

★ It takes approximately 10,000 years for a shark tooth to become a true fossil.

★ Gordon Hubbell holds the world record for the largest collection of shark teeth in the U.S., and most likely, on Earth. He also has an extensive collection of shark jaws.

★ An average days worth of shark tooth collecting on a Florida beach would still amount to less than the minimum wage in the sate of Florida.

Collections Housed in Riker Displays

Most serious shark tooth collectors chose to store their shark teeth in Riker displays. These are black leatherette paper covered cardboard box with glass top and locking pins , filled with white poly fill. They are used by collectors to display pins, gems, awards, insects or any thing else.

See Also

★ Megalodon

★ List of sharks

★ Elasmobranch

References

1. Cartmell, B.C. "Let's Go Fossil Tooth Hunting. A Guide for Identifying Sharks and Where and How to Find Their Superbly Formed Fossilized Teeth". 8th printing. Natural Science Research, Venice, Florida, March 1993;7,13,15.
2. Cocke,J. "Fossil Shark Teeth of the World. A Collector's Guide". Lamna Books, Torrance, CA 2002;2 -5.
3. Hennemann RM. Sharks & Rays: Elasmobranch Guide of the World". IKAN-Unterwasserarchiv, Frankfurt, Germany 2001;266 - 269.
http://www.megalodonteeth.com/about.html

★ The Sharks of North American Waters, , Jose, Castro, Texas A&M University Press, , ISBN 0-89096-143-3

★ Sharks, , John D., Stevens, NY Facts on File Publications, , ISBN 0-8160-1800-6

External Links

★ http://www.megalodonteeth.com/about.html