|MadSci Network: Zoology|
The Miocene (23 to 5 mya) Florida (as well as the rest of the Atlantic coastline) was part of a warm and shallow sea as early as 10 - 20 million years ago. (For a view of a world map during the Miocene, please visit: http://www.scotese.com/miocene.ht m ). *** Almost everything we know about these ancient beasts we have learned from their fossils in the geologic record and from studying their decendents. Fossil teeth in the Maryland coastal Miocene deposits (Calvert Cliffs in Calvert County) show that Tiger Sharks (Galeocerdo contortus, G. triqueter), Requiem Shark (Hemipristis serra), Mackerel Shark (Oxyrhina desorii), Hammer-head shark (Shyrma prisca), Sand Shark (Odontaspis elegans), and occasionally White Shark (Carcharondon megalodon) swam the Miocene waters. (http://www.mgs.md.gov/esic/brochures/sharks.html) Sometimes these sharks are referred to as the “Miocene Monsters.” The 40- 50 foot white shark, Carcharodon megalodon (aka “Megatooth”), has been estimated as weighing eight times that of a great white shark (about 77,092 lbs. for the largest Megatooth found [http://www.flmnh.ufl.edu/fish/sharks/innews/megatoothshark.htm]), and had 300 serrated teeth with which the carnivore would eat whales. (http://home1.gte.net/fossils/rep1.htm). In general, sharks are great predators who readily adapt to their environment. Over time, shark’s have evolved fantastic senses of smell and movement, better jaws and more efficient teeth. Shark skeletons are cartilaginous (cartilage [fibruous tissue] instead of bone) and weigh less than hard bone, giving the creature natural buoyancy. The natural buoyancy, when coupled with strong muscles, flexibility, fast speed and keen senses make for a powerful predator. In addition to sharks, many other creatures inhabited the sea at this time, including whales, porpoises, sea cows, sea turtles, and crocodiles. (http://www.geobop.com/paleozoo/World/NA/US/MD/#MARYLAND) These creatures were probably a food source for the Miocene Monsters. Today, the Miocene Monster ancestors eat a variety of foods. Hammerhead sharks eat fish and squid. Modern Tiger Sharks eat indiscriminately anything they can catch. The requiem family of sharks (of which Tiger Shark is a member) are given their name “requiem” (which means a hymn or mas for the dead) for that very reason! (http://www.chirpingbird.com/netpets/html/classrm/fishfac1.html ) For more information on the diet and eating habits of the Miocene Monster ancestors, please visit: http://www.seaworld.org/Sha rks/diet.html ****IF ANY OF THE LINKS IN THIS ANSWER DO NOT WORK DIRECTLY, PLEASE CUT AND PASTE THEM INTO THE ADDRESS BAR OF A NEW BROWSER. More Information On Shark Teeth: Galeocerdo contortus teeth: http://www.it ano.net/fossils/maryland/contortus01s.htm Hemipristis serra teeth: http://www.itano.n et/fossils/maryland/hemip1s.htm Miscellaneous Shark Teeth Catalog: http://www.megalodon teeth.com/html/misccat.html For more general information on extinct and modern sharks: Fiona's Shark Links Galore: http://www.p ostmodern.com/~fi/sharklinks/links.htm#orgs Listing of Fossil Sharks and Rays of the World: http://www.afn.org/~afn028 77/ielasmo.html Gainesville Fossil Shark Teeth: http://www.afn.org/~afn0287 7/sharkt.html Fossils of Calvert Cliffs http://calvert-county.com/fossils.htm
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