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Diamantinasaurus matildae (Hocknull et al. 2009)

dye-ah-man-teen-ah-sor-us  mah-til-day

Matilda's Diamantina (River) Lizard

Sauropoda, Titanosauria, Lithostrotia

Winton Formation, central western Queensland

Mid-Cretaceous (Latest Albian) 100-98 million years ago

Approximately 15 to 16 m long

Approximately 2.5 m high at the hip

Approximately 15 to 20 tonnes

June, 2005

Australian Age of Dinosaurs Museum of Natural History (AAOD)

Holotype specimen (AODF 603): Right scapula (shoulder blade), right and left humeri (upper forelimb), right ulna (lower forelimb), near complete right metacarpus including metacarpals II-V (front foot), phalanges and a manus ungual (claw). Left metacarpal I (toe bone). Dorsal (trunk) ribs and fragmentary gastralia (stomach ribs). Left sternal plate (breast plate). Left ilium (upper pelvis) and isolated sacral processes. Right and left pubes and ischia (lower pelvis). Right femur (thigh bone), tibia (shin bone), fibula (shin bone) and astragalus (ankle bone). Additional material awaits preparation.

Silhouette reconstruction of Matilda showing articulated fossil specimens described to date from the right (top) and left sides (from Hocknull et al. 2009).

MATILDA'S DIAMANTINA LIZARD

The skeleton of Diamantinasaurus matildae is one of the most robust dinosaur skeletons ever to have been found in Australia. The limb bones are much more massive than those of Wintonotitan wattsi, even though both were of a similar overall size.

The massive size of Matilda is reflected in the limbs and pelvic girdle; where each bone is very robust and stocky in appearance. This has lead to the reconstruction of Matilda as a wide-hipped and bow-legged dinosaur with a rotund appearance.

 

The overall appearance of Diamantinasaurus matildae reflects a couple of possible behaviours, the first being that it might have been able to stand on its hind legs with the tail for support (tripodal stance). The second possible behaviour is that of a semi-aquatic animal, using the billabongs that eventually preserved their fossils, as a wallow. Although it's hard to determine either of these behaviours, the preservation of Matilda suggests it was not living far from the billabong that it eventually ended up in. Perhaps it lived some of its life in the billabongs or water courses, like hippos do today as a wallowing plant-eating dinosaur filling the niche of a hippo way back in the Cretaceous Period.

New mid-Cretaceous (late Albian) dinosaurs from Winton, Queensland, Australia. (2009) PLoS ONE, 4(7): e6190. doi:10.1371/journal.pone.0006190

Scott A. Hocknullª, Mathew A. Whiteº, Travis R. Tischlerº, Alex G. Cookª, Naomi D. Callejaº, Trish Sloanº, David A. Elliottº

ª Geosciences, Queensland Museum, 122 Gerler Rd. Hendra, Queensland, Australia, 4011.