Post by Deinobrontornis on Nov 6, 2011 16:48:21 GMT -5
[a href="Xiphactinus"]Xiphactinus[/a]
Xiphactinus (from Latin and Greek for "sword-ray") was a large, 4.5 to 6 m (15 to 20 feet) long predatory bony fish that lived in the Western Interior Sea, over what is now the middle of North America, during the Late Cretaceous. When alive, the fish would have resembled a gargantuan, fanged tarpon (to which it was, however, not related). The Portheus molossus described by Cope is a junior synonym of the species. Skeletal remains of Xiphactinus have come from Kansas (where the first Xiphactinus fossil was discovered during the 1850s), Alabama, and Georgia in the United States, as well as Europe, Australia and Canada.
Palaeobiology:
Xiphactinus audax was a voracious predator fish. At least a dozen specimens have been collected with the remains of large, undigested or partially digested prey in their stomachs. In particular, one 13 feet (4.0 m) fossil specimen was collected by George F. Sternberg with another, nearly perfectly preserved 6 feet (1.8 m) long ichthyodectid Gillicus arcuatus, inside of it. The larger fish apparently died soon after eating its prey, most likely due to the smaller fish prey struggling and rupturing an organ as it was being swallowed. This fossil can be seen at the Sternberg Museum of Natural History in Hays Kansas.
Like many other species in the Late Cretaceous oceans, a dead or injured X. audax was likely to be scavenged by sharks (Cretoxyrhina and Squalicorax). The remains of a Xiphactinus were found within a large specimen of Cretoxyrhina collected by Charles H. Sternberg. The specimen is on display at the University of Kansas Museum of Natural History.
Virtually nothing is known about their larval or juvenile stages. The smallest fossil specimen of X. audax consists of a tooth bearing premaxilla and lower jaws of an individual estimated to be about 12 inches (30 cm) long.
The species and all other ichthyodectids went extinct near the end of the Late Cretaceous as the Western Interior Seaway began to recede from the middle of North America - see Cretaceous-Tertiary extinction event.
An incomplete skull of what may be a new species of Xiphactinus was found in 2002 in the Czech Republic, in a small town called Sachov next Borohradek city, by student Michal Matejka.
In July 2010 the bones of a Xiphactinus were discovered near Morden, Manitoba, Canada. The specimen is about six metres long and was found with the flipper of a mosasaur between its jaws.
In popular culture:
X. audax was one of the predators featured in the BBC's Sea Monsters, as well as National Geographic's Sea Monsters: A Prehistoric Adventure.
In October 2010, Kansas House Rep. Tom Sloan (R-Lawrence) announced that he would introduce legislation to make Xiphactinus, the "X-fish," the state fossil of Kansas.
Xiphactinus (from Latin and Greek for "sword-ray") was a large, 4.5 to 6 m (15 to 20 feet) long predatory bony fish that lived in the Western Interior Sea, over what is now the middle of North America, during the Late Cretaceous. When alive, the fish would have resembled a gargantuan, fanged tarpon (to which it was, however, not related). The Portheus molossus described by Cope is a junior synonym of the species. Skeletal remains of Xiphactinus have come from Kansas (where the first Xiphactinus fossil was discovered during the 1850s), Alabama, and Georgia in the United States, as well as Europe, Australia and Canada.
Palaeobiology:
Xiphactinus audax was a voracious predator fish. At least a dozen specimens have been collected with the remains of large, undigested or partially digested prey in their stomachs. In particular, one 13 feet (4.0 m) fossil specimen was collected by George F. Sternberg with another, nearly perfectly preserved 6 feet (1.8 m) long ichthyodectid Gillicus arcuatus, inside of it. The larger fish apparently died soon after eating its prey, most likely due to the smaller fish prey struggling and rupturing an organ as it was being swallowed. This fossil can be seen at the Sternberg Museum of Natural History in Hays Kansas.
Like many other species in the Late Cretaceous oceans, a dead or injured X. audax was likely to be scavenged by sharks (Cretoxyrhina and Squalicorax). The remains of a Xiphactinus were found within a large specimen of Cretoxyrhina collected by Charles H. Sternberg. The specimen is on display at the University of Kansas Museum of Natural History.
Virtually nothing is known about their larval or juvenile stages. The smallest fossil specimen of X. audax consists of a tooth bearing premaxilla and lower jaws of an individual estimated to be about 12 inches (30 cm) long.
The species and all other ichthyodectids went extinct near the end of the Late Cretaceous as the Western Interior Seaway began to recede from the middle of North America - see Cretaceous-Tertiary extinction event.
An incomplete skull of what may be a new species of Xiphactinus was found in 2002 in the Czech Republic, in a small town called Sachov next Borohradek city, by student Michal Matejka.
In July 2010 the bones of a Xiphactinus were discovered near Morden, Manitoba, Canada. The specimen is about six metres long and was found with the flipper of a mosasaur between its jaws.
In popular culture:
X. audax was one of the predators featured in the BBC's Sea Monsters, as well as National Geographic's Sea Monsters: A Prehistoric Adventure.
In October 2010, Kansas House Rep. Tom Sloan (R-Lawrence) announced that he would introduce legislation to make Xiphactinus, the "X-fish," the state fossil of Kansas.
