Wednesday 26 June 2013

A new species of Diplodocid Dinosaur from the Late Jurassic of northern Wyoming.

Diplodocids were members of the Sauropod group of Dinosaurs, noted for their extremely long necks and tails; they were less massive than the related Titanosaurids and Brachiosaurs, but were longer and more slender, making them probably the longest animals ever to live; the longest species, Diplodocus and Supersaurus, are thought to have reached around 34 m, making them longer than a Blue Whale (though considerably less massive). The ecology of the Diplodocids is somewhat mysterious; their light frame and long bodies makes it seem unlikely that they had the musculature to lift their necks very high, and they had relatively short legs compared to other Sauropods, ruling out Giraffe-style treetop feeding. Some palaeontologists have described them as 'Dachshund' Dinosaurs.

In a paper published in the Journal of Systematic Palaeontology on 27 January 2013, Emanuel Tschopp of the Faculdade de Ciências e Tecnologia at the Universidade Nova de Lisboa and Octávio Mateus of the Museu da Lourinhã describe a new species of Diplodocid Dinosaur from the Late Jurassic Morrison Formation at Howe Quarry near Shell,Wyoming.

The new Dinosaur is named Kaatedocus siberi, where the Crow word 'Kaate' (small) has been combined with the element '-docus' (beam) from Diplodocus, to make 'small-beam' or 'small-Diplodocus', and 'siberi is in honour of Hans-Jakob Siber, who founded the Sauriermuseum Aathal, near Zurich, and who was involved in the organization and funding of the expedition which found the new specimen, as well as its subsequent preparation and curation.

Kaatedocus siberi is described from a partial skull and a series of cervical (neck) vertebrae. It is thought to have been a young animal, with weekly fused bones and a head and neck length of about 3.8 m and a total body length of 14 m. 

The reconstructed skull of Kaatedocus siberi in right lateral view. (A) Photograph. (B) Drawing. Light grey areas in (B) are reconstructed parts. Abbreviations: a: articular;  aof: antorbital
fenestra; bt: basal tuber; d: dentary;  f: frontal;  ltf: laterotemporal fenestra; m: maxilla; o: orbit;
os: orbitosphenoid; p: parietal; pm: premaxilla; po: postorbital; popr: paroccipital process;  pra: proatlas; q: quadrate; qj: quadratojugal; sq: squamosal. Scale bar is 5 cm. Tschopp & Mateus (2013).

The reconstructed skull of Kaatedocus siberi in right lateral view. (A) Photograph. (B) Drawing. Abbreviations: a: articular; aof: antorbital fenestra; bt: basal tuber; d: dentary; f: frontal; la: lacrimal; ls: laterosphenoid; ltf: laterotemporal fenestra; m: maxilla; o: orbit; p: parietal; paof: preantorbital fossa; po: postorbital; popr: paroccipital process; pre: pre-epipophysis; pro: prootic; q: quadrate; qj: quadratojugal; sa: surangular; sq: squamosal. Scale bar is 5 cm. Tschopp & Mateus (2013).

The reconstructed skull of Kaatedocus siberi in dorsal view. (A) Photograph. (B) Drawing. Abbreviations: a: articular; aof: antorbital fenestra; f: frontal; ls: laterosphenoid; m: maxilla; n: external nares; o: orbit; p: parietal;  pm: premaxilla; po: postorbital; popr: paroccipital process; ppfo: postparietal foramen; pra: proatlas; q: quadrate; sq: squamosal. Scale bar is 5 cm. Tschopp & Mateus (2013).

Life reconstruction of the skull of Kaatedocus siberi. Note the lateral spur on the lacrimal and the palpebral element covering the orbit. Illustration by Davide Bonadonna in Tschopp & Mateus (2013).

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