Diamantinasaurus

Live reconstruction of Diamantinasaurus matildae. From zero Hock and colleagues, 2009.

• Australia, Queensland ( Winton Formation)

• Diamantinasaurus matildae

Diamantinasaurus is a genus of sauropod dinosaur from the group of Titanosauria who lived in the Lower Cretaceous of Australia.

This species was first scientifically described by the single species, Diamantinasaurus matildae 2009. Previously, a fragmentary skull -less skeleton is known, which consists of the shoulder girdle, the front leg, pelvis, and parts of the hind legs and dates from the late Albian of the Winton Formation of Queensland.

Diamantinasaurus was derived ( modern ) Titanosaurier, which is included in the group Lithostrotia; the same group, which also includes the better known genera Opisthocoelicaudia and Saltasaurus. Unique for a derived Titanosauria is the presence of a hand claw.

Features

Diamantinasaurus was about 16 feet long. This genus can be distinguished by a unique combination of features from other genres. Thus, the shoulder blade (scapula ) was flat and rectangular in cross section. The upper portions of the ribs were pneumatized, i.e. with numerous air-filled chambers traversed. The upper arm bone (humerus ) and the ulna ( ulna ) were very stocky - the thickness of the upper ( proximal ) end of the humerus was about 50 % of its total length. The lower condyle of the humerus were flat and connected. The metacarpal bones ( metacarpals ) were massive, showed undivided condyles and were at the lower (distal) end rough. As with other Titanosauria the phalanges were greatly reduced: So only reported four of the original five finger phalanges on - the Phalangenformel is 2-1-1-1-0.

On the first finger ( thumb) a claw ( ungual ) was present - so that is the first Diamantinasaurus Titanosauria in which a hand claw was detected. The phalanx of the third finger was greatly reduced and is considered an autapomorphy of this genus ( unique feature ). The ilium ( ilium ) was solid and showed as with other representatives of the Titanosauriformes a club-like crest on the front ( präacetabularen ) half, which was oriented perpendicular to the axis of the sacrum. The thigh bone (femur) is robust and shows the typical Titanosauriformes lateral hump. Also shinbone ( tibia) and fibula ( fibula ) were relatively robust.

Characteristics that allow a classification within the Titanosauria include, for example, the crescent-shaped chest (sternum ) with a. In addition, Elle showed a bone spur at the upper end ( olecranon ), which extended over the articular surface of the ulna. In addition, the shin as other Titanosauria the lower (distal) end was twice as thick as the shank.

Other features that allow a classification within the Lithostrotia, for example, show the scapula that forms a 45 ° angle with the coracoid ( coracoid ), and the thigh bone, which shows a highly eccentric cross-section and are not its lower condyles perpendicular to the shaft axis are, but inclined relative to the vertical alignment. These features of the femur probably hang together with the evolution of another leg position within the Titanosauria.

System

Diamantinasaurus is classified as a derived representative of Titanosauria within the group Lithostrotia. The systematic position within the Lithostrotia remains unclear - so this genus is provisionally out as incertae sedis Lithostrotia.

Fund and naming

The bones were recovered Museum between 2006 and 2009 excavations of the Australian Age of Dinosaurs Museum of Natural History and the Queensland. These excavations brought to a total of two sites at least two new dinosaur species to the fore: the Titanosauriformen Wintonotitan and the Allosauroiden Australovenator. Dinosaur finds from Australia are compared with the many findings of other continents extremely rare. However, researchers in Australia see a great potential for further discoveries.

The skeleton found ( holotype, specimen number AODF 603 ) consists of the scapula, sternum, humerus, ulna, a nearly complete metatarsal, phalanges, a claw, ribs, fragmentary belly ribs ( Gastralia ), ilium, elements of the sacrum, pubis, ischium, femur, tibia, fibula, and a talus ( astragalus ).

The skeleton comes from the " Matilda - reference ", which is about 60 km north - west is the city of Winton in western Queensland. Stratigraphically the rocks include the reference to the lowest Winton Formation, which was deposited in the late Albian. The fossils were found between two layers of sandstone within a layer of clayey sediment. These sediments are considered as the deposits of a Altarms - a cut-off oxbow lake ( oxbow lake) - interpreted. In addition to the Diamantinasaurus fossils of the locality contained the skeleton of Australovenator, the most complete skeleton of a theropod from Australia. Furthermore, the locality contains the remains of fish, crocodile -like, turtles and clams.

The name Diamantinasaurus ( "lizard from the Diamantina River " ) has the Diamantina River in the vicinity of the site. The Artepitheth matildae has the famous Australian folk song " Waltzing Matilda", in 1895 wrote the poet Banjo Paterson in Winton and was proposed as the official Australian national anthem.