are sharks one of the oldest species?
Since then, sharks have diversified into over 500 species. They range in size from the small dwarf lanternshark (Etmopterus perryi), a deep sea species of only 17 centimetres (6.7 in) in length, to the whale shark (Rhincodon typus), the largest fish in the world, which reaches approximately 12 metres (40 ft) in length. Sharks are a group of fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. Sharks have swum in the oceans for almost 450 million years. But longevity is only part of the story. That extra few million years of evolution have enabled many shark species to develop some extraordinary abilities as perfect predators. They have numerous sets of replaceable teeth. Well-known species such as the great white shark, tiger shark, blue shark, mako shark, and the hammerhead shark are apex predators—organisms at the top of their underwater food chain. Many shark populations are threatened by human activities. We need to take care of ourselves, too! We've got delicious and easy recipes, the latest fashion and home decor trends, health topics that impact every woman and so much more. So grab a cup of coffee and dig in. Goblin Shark - 118 million years old. Goblin sharks are among the most terrifying creatures to behold, and for that reason, we're glad they dwell at the bottom of the ocean and rarely stray from there. That's why humans have so infrequently laid eyes on these beasts, even though they've been on Earth for as long as we have and much longer. A live goblin shark was caught in Japan in January 2007, but it died within days. List of sharks. Sharks belong to the superorder Selachimorpha in the subclass Elasmobranchii, in the class Chondrichthyes. The Elasmobranchii also include rays and skates; the Chondrichthyes also include Chimaeras. The first sharks appeared in the oceans over 440 million years ago. Listed below are extant species of shark. Sharks are spread across 512 described species in eight orders. The families and genera within the orders are listed in alphabetical order. Also included is a field guide to place sharks into the correct order. World's Oldest Shark Fossil Found. Add another name to the tide of Canadian rock stars. Paleontologists announced today they've unearthed the world's oldest, intact shark fossil—a 409-million-year-old specimen of a small, primitive species known as Doliodus problematicus—from a site in New Brunswick, Canada. Printer Friendly. Intact fossils of sharks, a boneless fish, are exceptionally rare. Many ancient shark species are known only by fossil teeth or skin scales. Until the recent find, Doliodus problematicus (Latin for a problematic deceiver), was among them. The oldest generally accepted shark scales are from about 420 million years ago, in the Silurian period. The first sharks looked very different from modern sharks. The majority of modern sharks can be traced back to around 100 million years ago. Most fossils are of teeth, often in large numbers.
Yes