Excalibosaurus
| Excalibosaurus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
,_Lyme_Regis,_England,_Early_Jurassic_-_Royal_Ontario_Museum_-_DSC09979.JPG)
Excalibosaurus costini , the dark fossil in the background |
||||||||||||
| Temporal occurrence | ||||||||||||
| Lower Jurassic ( Hettangian to Sinemurian ) | ||||||||||||
| 201.3 to 190.8 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Excalibosaurus | ||||||||||||
| McGowan , 1986 | ||||||||||||
Excalibosaurus (after Excalibur and sauros Gr . = Lizard) is a genus of ichthyosaurs whose fossil remains, an incomplete skeleton, were found in 1984 in layers of the early Lower Jurassic of Somerset . The fossil includes the skull, forefins and shoulder girdle, vertebrae and ribs and is now in the Bristol City Museum and Art Gallery . So far only one species, Excalibosaurus costini , is known. The name is derived from the mythical sword Excalibur.
features
Excalibosaurus had a spindle-shaped body reaching a length of 5.4 to 6.9 meters. The upper jaw was elongated and protruded beyond the lower jaw, a feature that only occurs in Eurhinosaurus . The skull has a length of 78.5 cm without the snout, the upper jaw is 60 cm long. Apart from the longer upper jaw, the skull resembles that of Leptonectes tenuirostris . The teeth are slender and are also located on the free part of the upper jaw. The front fin was half as long as the upper jaw and thus shorter than that of Eurhinosaurus whose forelimbs reached the length of the upper jaw. The forefin consisted of three fingers, with some indications for a fourth. The middle finger had twelve limbs (hyperphalangia).
Systematics
Excalibosaurus was probably a predecessor of Eurhinosaurus . Together with Leptonectes and Eurhinosaurus , Excalibosaurus is part of the Leptonectidae family .
literature
- Chris McGowan: A putative ancestor for the swordfish-like ichthyosaur Eurhinosaurus. In: Nature . Vol. 322, No. 6078, 1986, pp. 454-456, doi : 10.1038 / 322454a0 .
- Chris McGowan: A new Specimen of Excalibosaurus from the English Lower Jurassic. In: Journal of Vertebrate Paleontology. Vol. 23, No. 4, 2003, ISSN 0272-4634 , pp. 950-956, doi : 10.1671 / 1860-20 .
- Richard Ellis : Sea Dragons. Predators of the Prehistoric Oceans. University Press of Kansas, Lawrence KS 2003, ISBN 0-7006-1269-6 , pp. 90-92.
