Stenopterygius
Stenopterygius | ||||||||||||
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![]() Stenopterygius quadriscissus with young animal. |
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Temporal occurrence | ||||||||||||
Lower Jurassic ( Toarcium ) | ||||||||||||
182.7 to 174.1 million years | ||||||||||||
Locations | ||||||||||||
Systematics | ||||||||||||
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Scientific name | ||||||||||||
Stenopterygius | ||||||||||||
Jaekel , 1904 |
![](https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Ichthyosaur_fossil.jpg/220px-Ichthyosaur_fossil.jpg)
Stenopterygius is a genus of ichthyosaurs from the early to middle Jurassic ( Toarcium - Aalenium ). Fossils of the genus have been found in England , France , Germany , Switzerland and Luxembourg . Stenopterygius is the most common ichthyosaur genus of the Holzmaden posidonia slate .
Hundreds of fully articulated skeletons have been found there, often showing the outer contours of the body. Only through these discoveries was it recognized that the ichthyosaurs had a shark-like dorsal fin and a sickle-shaped caudal fin. Some of the fossils have embryos in the body or young animals that have just been born.
features
Stenopterygius is difficult to diagnose by inferred traits , and the genus may be paraphyletic . It was about three to four meters long. The pectoral and ventral fins were of medium length. The pectoral fins had four main fingers and a shorter fifth finger, the pelvic fins three fingers and a reduced fourth. Older specimens were partially toothless. Behind the orbit , the skull is very short, the temporal window is large, the maxillary (upper jawbone), the palatine bone and the quadratojugale (another skull bone) were short. In front of the sacrum, Stenopterygius had 44 to 46 vertebrae.
Systematics
Stenopterygius belongs to the group of Thunnosauria, a group of advanced ichthyosaurs that had a spindle-shaped, stiffened body and, like the tuna, only moved quickly through the water with the tails of their tail fins.
species
- Stenopterygius quadriscissus (Quenstedt, 1856) Jaekel, 1904 ( type species )
- Stenopterygius longifrons (Owen, 1881)
- Stenopterygius hauffianus von Huene, 1922 (possibly identical to Stenopterygius quadriscissus )
- Stenopterygius uniter von Huene, 1931 (synonym Stenopterygius megalorhinus von Huene, 1922)
- Stenopterygius aaleniensis Maxwell et al., 2012
literature
- Robert L. Carroll : Paleontology and Evolution of the Vertebrates. Thieme, Stuttgart et al. 1993, ISBN 3-13-774401-6 .
- Richard Ellis : Sea Dragons. Predators of the Prehistoric Oceans. University Press of Kansas, Lawrence KS 2003, ISBN 0-7006-1269-6 .
- Michael W. Maisch, Andreas T. Matzke: The Ichthyosauria (= Stuttgart contributions to natural history. Series B: Geology and palaeontology. No. 298, ISSN 0341-0153 ). State Museum for Natural History, Stuttgart 2000, pp. 67–68, (digital copy PDF; 2.09 MB) .
Web links
- Ryosuke Motanis Ichthyosaur Page Classification
- The Paleobiology Database: Stenopterygius