Efraasia
Efraasia | |
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Reconstructed skull | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | †Sauropodomorpha |
Clade: | † Bagualosauria
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Genus: | †Efraasia Galton, 1973 |
Type species | |
†Efraasia minor (von Huene, 1907–1908 [originally Teratosaurus minor])
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Synonyms | |
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Efraasia (pronounced "E-FRAHS-ee-A") is a
The specimens were at first assigned to three already existing genera and so became divided among three separate species: Teratosaurus minor, Sellosaurus fraasi and Paleosaurus diagnosticus. In 2003 these were combined into a single valid species: Efraasia minor.
Efraasia was a lightly built, medium-sized sauropodomorph, about 6 to 7 metres (20 to 23 ft) long.
Discovery and naming
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/29/Wei%C3%9FerSteinbruchSandsteinformation.jpg/220px-Wei%C3%9FerSteinbruchSandsteinformation.jpg)
Efraasia has had a complicated
A specimen of a basal sauropodomorph, SMNS 11838, was first described by
In 1912,
In 2003, Adam Yates published a study incorporating these and other fossils from the Late Triassic of Germany.[9] He found that the "Sellosaurus" material fell into two clusters. One included the original Sellosaurus gracilis, which he assigned to Plateosaurus as P. gracilis. The other included "Teratosaurus" minor, "Sellosaurus" fraasi, and "Palaeosaurus" diagnosticus. Efraasia was the oldest valid generic name for these fossils. The specific name could not be determined as simply, as both Teratosaurus minor and Sellosaurus fraasi had first appeared in von Huene's 1908 book. Because the former name had page priority, Yates chose minor as the specific name, providing for the type species Teratosaurus minor the new combination Efraasia minor, which is thus the single valid species name of the taxon.[8] Yates did not take into account two other species based by von Huene on very fragmentary German basal sauropodomorph material, Teratosaurus trossingensis and Thecodontosaurus hermannianus, though Galton had considered them junior synonyms of Efraasia diagnostica in 1990.[10]
Apart from the specimens mentioned above, mostly consisting of rather complete skeletons preserved in large slabs, though not fully prepared from the rock matrix, several other fossils have been found. Together they allow for a good impression of what the animal looked like.
Description
![](http://upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Efraasia_Scale.svg/220px-Efraasia_Scale.svg.png)
Efraasia was once thought to be a relatively small dinosaur, about 2 to 3 metres (6.6 to 9.8 ft) long, but this was because the most complete known fossils are from juvenile animals. Yates in 2003 has estimated the adult length at 6.5 metres (21 ft); the largest specimen is SMNS 12843 with a
, so that the hand could not be directed downward, making the animal an obligate biped.The skull is small, pointed and triangular. There are four teeth in the premaxilla. The neck is only moderately elongated but thin. The neural spines of the tail are low. The second finger is longer than the third finger. The first toe is not strongly reduced. Von Huene identified a cluster of stomach stones (gastroliths) in association to specimen SMNS 12667.
Yates identifies two unique derived traits (autapomorphies): the presence of a raised crescent-like ridge on the upper part of the inner side of the pubis shaft; and the presence of a vaulted bony web between two lower extensions of a braincase bone, the processus basipterygoidei, with a raised central bony platform on top of the vault.
Classification
Von Huene continued interpreting these forms as predatory dinosaurs, in 1932 assigning them to a separate family
In 1973 Galton assigned Efraasia to the
References
- ^ F. v. Huene, 1908, Die Dinosaurier der Europäischen Triasformation mit berücksichtigung der Ausseuropäischen vorkommnisse. Geologische und Palaeontologische Abhandlungen Suppl. 1(1): 1-419
- ^ E. Fraas, 1912, "Die schwäbischen Dinosaurier", Jahreshefte des Vereins für Vaterländische Naturkunde in Württemberg 68: 56-57
- ^ Huene, F. von, 1932, Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte: Monographien zur Geologie und Palaeontologie, 1e Serie, Heft 4, pp. 1-361
- ^ Kuhn, O., 1959, "Ein neuer Microsaurier aus dem deutschen Rotliegenden", Neues Jahrbuch für Geologie und Palaeontologie. Monatshefte 9: 424-426
- ^ Appleby, R.M.; Charig, A.J., Cox, C.B.; Kermack, K.A. & Tarlo, L.B.H., 1967, "Reptilia", In: (Harland, B. e.a. ed.) The Fossil Record, Geological Society of London, pp 695-731
- ^ P.M. Galton, 1973, "On the anatomy and relationships of Efraasia diagnostica (Huene) n.gen., a prosauropod dinosaur (Reptilia: Saurischia) from the Upper Triassic of Germany", Paläontologische Zeitschrift 47(3/4): 229-255
- ^ Galton, P.M. & Bakker, R.T., 1985, "The cranial anatomy of the prosauropod dinosaur "Efraasia diagnostica", a juvenile individual of Sellosaurus gracilis from the Upper Triassic of Nordwürttemberg, West Germany", Stuttgarter Beiträge zur Naturkunde B, 117: 1-15
- ^ ISBN 0-7864-2295-5.
- ^ *A.M. Yates, 2003, "The species taxonomy of the sauropodomorph dinosaurs from the Löwenstein Formation (Norian, Late Triassic) of Germany", Palaeontology 46(2): 317-337
- ^ Galton, P.M. 1990. "Basal Sauropodomorpha-Prosauropoda". Pp. 320-344 in: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.), The Dinosauria. University of California Press, Berkeley
- ISBN 1-84028-152-9.
- ^ Charig, A.J.; Attridge, J. & Crompton, A.W., 1965, "On the origin of the sauropods and the classification of the Saurischia", Proceedings of the Linnean Society of London 176: 197-221
External links
- Sauropodomorpha from Palaeos.com