Shark teeth dating
Sharks and their relatives were diverse in the Paleozoic, but most of them were not directly related to living sharks, belonging instead to side groups that died out in the Permian or Triassic.
Living sharks, rays, and skates belong to a group known as the Neoselachii.
Various holocephalian fish (those with an upper jaw fused to the braincase) appeared about the same time the earliest sharks did, in the Devonian.
They probably included the ancestors of the living chimaeras and ratfish, as well as some other groups that are now extinct (traditionally classified in the Iniopterygii), but their relationships are not well understood. You may be able to identify them using the Key to Common Genera of Neogene Shark Teeth, by Robert W.
A geologist made the incredible discovery while leading a team of volunteers excavating part of Naples, in Italy.
Paleontogist Gianluca Minin made the discovery at Naples' Galleria Borbonica, a sprawling underground network which was once used as an escape route for King Ferdinand II.
The sharks teeth are found along the beaches, sand bars, and in and around the kaolin mines.
Sharks and their kin are sometimes described as "living fossils," and they are indeed part of an ancient clade of vertebrates.
Aside from these finds, the oldest known complete, identifiable cartilaginous fish date from the middle Devonian.One of the largest extinct species of shark tooth was Otodontidae Carcharocles megalodon.Otodontidae Carcharocles megalodon Although the shark’s cartilaginous skeleton is rarely preserved, its teeth, which are constantly replaced during a shark’s lifetime, are preserved in great quantities.Shark and ray teeth, and sometimes calcified vertebrae, are common fossils in many Cretaceous and Cenozoic deposits.One of the more famous fossil sharks is the Miocene Carcharodon megalodon, with serrated, triangular teeth (pictured on the background of this page) ranging up to 17.5 cm (7 inches) in length. Scales of thelodont and shark-like fishes from the Ordovician of Colorado.