Pachycormidae

Life image of Protosphyraena perniciosa

• Europe, Asia, North and South America

The Pachycormidae are an extinct family of marine bony fishes ( Osteichthyes ). They stand alone in order Pachycormiformes and lived from the Middle Jurassic to the Cretaceous.

Features

Most genera of Pachycormidae were tuna or swordfish -like predators that caught their prey in high-speed chases. They had long moved out, scythe blade-like pectoral fins, pelvic fins were small or absent altogether. The caudal fin is the tail fin and homocerk skeleton corresponds to the genuine bony fish ( Teleostei ). Most species have a more or less long been coated rostrum. The clearest this feature was pronounced in Protosphyraena perniciosa from the Cretaceous period.

Within the Pachycormidae there is an existing five species monophyletic clade, large mariner, of filtering plankton feeders. The group took over a period of 100 million years ago in the upper Mesozoic an ecological role that is today occupied by the baleen whales and some plankton -eating fish cartilage. This group includes the two-meter length reach genera Astenocormus and Martillichthys, the five-meter- long expectant Bonnerichthys and Leedsichthys problematicus, who is ever with a length of nine meters, the largest bony fish.

System

The Pachycormidae was initially classified as Knochenganoiden ( Holostei ), a taxon that is now considered paraphyletic and in modern systematics is no longer common. Joseph S. Nelson arranged them as very sophisticated, the genuine bony fish ( Teleostei ) very similar Neuflosser ( Neopterygii ) a. In a publication dated January 2010, she will finally assigned to the Teleostei.

Genera

• Eugnathides
• Euthynotus Wagner, 1860
• Hypsocormus Wagner, 1860
• Orthocormus Weitzel, 1930
• Pachycormus Agassiz, 1833
• Prosauropsis
• Protosphyraena Leidy, 1857
• Sauropsis Agassiz, 1832
• Saurostomus Agassiz, 1833
• Clade of marine plankton Astenocormus Woodward, 1895
• Bonnerichthys ( Cope, 1874)
• Leedsichthys Woodward, 1889
• Martillichthys
• Rhynchonichthys Friedman et al. 2,010

Extinction

The Pachycormidae, including the massive marine plankton feeders, died out along with Dino and pterodactyls and the large marine reptiles at the end of the Cretaceous - Tertiary boundary. The ecological niche of filtering large plankton feeders remained unfilled at first, then was from the late Paleocene of manta rays and whale sharks, taken from the baleen whales since the Middle Eocene of basking sharks and the Eocene - Oligocene boundary. Only the giant sharks mouth, also navy, filtering plankton eaters, whose ancestors can be safely detected since the Oligocene - Miocene boundary, could be already been contemporaries of the Pachycormidae, whereupon indicate some fossil teeth from the Early Cretaceous. The only major, recent bone fish, which is also a of filtering plankton feeders, the paddlefish that lives in fresh waters of North America, and reaches with his long extended rostrum, a length of two meters ..