Betasuchus

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Betasuchus
Cast of the femur, exhibited in Brussels

Cast of the femur, exhibited in Brussels

Temporal occurrence
Maastrichtium ( Upper Cretaceous )
72 to 66 million years
Locations
Systematics
Dinosaur (dinosauria)
Lizard dinosaur (Saurischia)
Theropoda
Ceratosauria
Betasuchus
Scientific name
Betasuchus
Huene , 1932
species
  • Betasuchus bredai ( Seeley , 1883)

Betasuchus is a dubious (doubtful) genus theropod dinosaur from the Upper Cretaceous the Netherlands . So far, only the upper end of a thigh bone (femur) is known, which originates from the Maastricht Formation ( Maastrichtium ) near Maastricht in the province of Limburg . It is the only find of a theropod from the Maastricht Formation to date. Today the find is in the collection of the British Museum of Natural History . The only species is Betasuchus bredai .

The systematic position is controversial. However, the latest study by Carrano and Sampson (2008) comes to the conclusion that it was the last (youngest) representative of the ceratosauria from Europe.

features

It was a relatively small theropod. Compared to other theropods of the Upper Cretaceous, the thigh bone is very primitive. The head was angled forward ( anteromedial ) and slightly upward (ventral). The small roll mound ( lesser trochanter ) is widened upwards. A rounded hill serves as the starting point for the iliofemoralis muscle .

Research history and systematics

The femur was originally described by Harry Seeley (1883) as a new species of the genus Megalosaurus , as Megalosaurus bredai . A re-description of the find by Friedrich von Huene (1926) showed, however, that this find cannot be ascribed to the genus Megalosaurus ( Megalosaurus was long used as a so-called wastebasket taxon , to which a large number of unrelated theropods were assigned). Instead, von Huene attributed the find to the ornithomimids , a group within the Coelurosauria , and referred to it provisionally and informally as Ornithomimidorum genus b ("Ornithomimosaur genus b"). Based on this designation, von Huene established the new genus Betasuchus in 1932 ( Greek beta - the second letter of the Greek alphabet; Greek soukhos - "crocodile").

The systematic classification of betasuchus is controversial: So was betasuchus by various authors as a representative of Coelurosauria - as a Ornithomimide or as one with Dryptosaurus related tyrannosaur - (indet theropods.) As discontinued unclassifiable theropod, or as a possible Abelisauride described. Carrano and Sampson (2008) classify Betasuchus as a representative of the Ceratosauria .

supporting documents

literature

  • Matthew T. Carrano, Scott D. Sampson: The Phylogeny of Ceratosauria (Dinosauria: Theropoda). In: Journal of Systematic Palaeontology. Vol. 6, No. 2, 2008, ISSN  1477-2019 , pp. 183-236, doi : 10.1017 / S1477201907002246 .
  • Eric Buffetaut : An additional hadrosaurid specimen (Dinosauria: Ornithischia) from the marine Maastrichtian deposits of the Maastricht area. In: Carnets de Géologie = Notebooks of Geology. Letter. 2009/03, (CG2009_L03), online .
  • John WM Jagt, Eric WA Mulder, Anne S. Schulp, Rudi W. Dortangs, René HB Fraaije: Dinosaurs from the Maastrichtian-type area (southeastern Netherlands, northeastern Belgium). In: Comptes Rendus Palevol. Vol. 2, No. 1, 2003, ISSN  1631-0683 , pp. 67-76, doi : 10.1016 / S1631-0683 (03) 00004-6 .
  • Friedrich von Huene : The fossil reptile order Saurischia, its development and history (= monographs on geology and palaeontology. Series 1, issue 4, ZDB -ID 634428-8 ). 2 parts (Part 1: text. Part 2: plates. ). Borntraeger, Leipzig 1932.

Individual evidence

  1. ↑ a b c d Carrano and Sampson , pp. 202, 204
  2. ↑ Buffetaut 2009 , p. 4
  3. ↑ Ben Creisler: Dinosauria Translation and Pronunciation Guide. Archived from the original on July 10, 2011 ; Retrieved April 9, 2012 .
  4. ↑ Huene 1932 , pp. 70-71
  5. ↑ Buffetaut 2009 , pp. 69–70