Friday, October 1, 2010
October 1, 2010 : Pliosaur (Extinct)
Pliosaurs were marine reptiles from the Jurassic and Cretaceous Periods. The pliosaurs, along with their relatives, the true plesiosaurs, and other members of Sauropterygia, were not dinosaurs. They originally included only members of the family Pliosauridae, of the Order Plesiosauria, but several other genera and families are now also included, the number and details of which vary according to the classification used.
The group was characterised by having a short neck and an elongated head, in contrast to the long-necked plesiosaurs. They were carnivorous and their long and powerful jaws carried many sharp, conical teeth. Pliosaurs range from 4 to 15 metres and more in length. Their prey may have included fish, ichthyosaurs and other plesiosaurs.
Typical genera include Kronosaurus, Liopleurodon, Pliosaurus and Peloneustes. Fossil specimens have been found in England, Mexico, South America, Australia and the Arctic region near Norway.
Many very early (from the Rhaetian (Latest Triassic) and Early Jurassic) primitive pliosaurs were very like plesiosaurs in appearance and indeed used to be included in the family Plesiosauridae.
The name "pliosaur" is derived from Greek, πλειων meaning "more/a higher degree" and σαυρος meaning "lizard". It is adapted from the name of the genus Pliosaurus, which means "more saurian", and was coined in 1841 by Richard Owen, who believed that pliosaurs represented a link between plesiosaurs and crocodilians (considered a type of "saurian"), particularly due to their crocodile-like teeth. Therefore, he named these animals to indicate that they were "more saurian" than the plesiosaurs.
The discovery of a very large pliosaur was announced in 2002, from Mexico. This pliosaur came to be known as the "Monster of Aramberri". The size of this specimen has been estimated to be about 15 metres (49 ft) long and it had a 3-metre (10 ft) long skull. Consequently, although widely reported as such, it does not belong to the genus Liopleurodon. The remains of this animal, consisting of a partial vertebral column, were dated to the Kimmeridgian of the La Caja Formation. The fossils were found much earlier, in 1985, by a geology student and were at first erroneously attributed to a theropod dinosaur by Hahnel. The remains originally contained part of a rostrum with teeth (now lost).
In August 2006, palaeontologists of the University of Oslo discovered the first remains of a pliosaur on Norwegian soil. The remains were described as "very well preserved as well as being unique in their completeness" and are the first complete skeleton of a pliosaur ever discovered. Whether it belongs to the genus Pliosaurus or Liopleurodon awaits publication of the fossil description. In the summer of 2008, the fossil remains of the huge pliosaur were dug up from the permafrost on Svalbard, a Norwegian island close to the North Pole. The excavation of the find is documented in the 2009 History television special Predator X.
On 26 October 2009 palaeontologists reported the discovery of potentially the largest pliosaur yet found. The fossil had a skull length of 2.4 metres (7 ft 10 in) and a body length of 16 metres (52 ft). Palaeontologist Richard Forrest told the BBC: "I had heard rumours that something big was turning up. But seeing this thing in the flesh, so to speak, is just jaw dropping. It is simply enormous."
The phrase "between Scylla and Charybdis" (popularly reworded "between a rock and a hard place") has come to mean being in a state where one is between two dangers and moving away from one will cause you to be in danger from the other.
Posts during October will be of real-life sea monsters, long extinct, as well as those of myth and folklore.