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Product Description
SEE MORE SIXGILL & SEVENGILL COW SHARK FOSSILS
This superb, LARGE display piece of original fossil-bearing Sharktooth Hill sandstone contains a RARE partial fossil tooth of the extinct Sixgill Cow Shark Hexanchus andersoni. The tooth is of maximum size with light salmon pink enamel still showing a natural luster. A great display and educational shark fossil to show what the surrounding soil is like in which these famous fossil shark teeth are found in. The matrix also often includes other fossil bones and teeth of fish, sea lion, whales and dolphins of various species.
HISTORY
Cow sharks are a shark family, the Hexanchidae, characterized by an additional pair or pairs of gill slits. Its 37 species are placed within the 10 genera: Gladioserratus, Heptranchias, Hexanchus, Notidanodon, Notorynchus, Pachyhexanchus, Paraheptranchias, Pseudonotidanus, Welcommia, and Weltonia.
Cow sharks are considered the most primitive of all the sharks, as their skeletons resemble those of ancient extinct forms, with few modern adaptations. Their excretory and digestive systems are also unspecialised, suggesting they may resemble those of primitive shark ancestors. Their most distinctive feature is the presence of a sixth, and, in two genera, a seventh, gill slit, in contrast to the five found in all other sharks.
Cow sharks are ovoviviparous, with the mother retaining the egg cases in her body until they hatch. They feed on relatively large fish of all kinds, including other sharks, crustaceans and carrion.
The only fossil records of the cow shark consist of mainly only isolated teeth
The rich Miocene fossil deposit known as "Sharktooth Hill" located in Bakersfield (Kern County), California has a reputation as the finest and most diverse fossil deposit of Miocene sharks, rays, bony fishes, turtles, birds and mammals (both marine and terrestrial) of the entire Pacific realm of North America. The formation is a result of silt spilling out of a prehistoric river delta into a Middle Miocene sea that once covered central California over 12 million years ago. This river originated in the nearby mountains east of Bakersfield. The fossil-bearing layer is thin ranging an average of only 6" - 18" thick but it spans approximately 100 square miles!
The 15 million year old bone bed in Bakersfield, California has a remarkable concentration of fossil specimens sometimes reaching up to several hundred specimens per cubic yard. It is also one of the most diverse, containing an extensive list of around 140 different vertebrate species as well as many invertebrates and plants. Of course, it is most famous for its fossil shark teeth!
