A new genus and species of sauropod dinosaur from the mid-Cretaceous has been discovered in western Queensland, Australia.
Savannasaurus elliottorum. Image credit: Travis R. Tischler.
The plant-eating sauropod dinosaur is called Savannasaurus elliottorum, and is thought to have lived about 95 million years ago.
A member of the sauropod subgroup called titanosaurs, it was approximately 45 feet (14 m) long, roughly half the length of a basketball court.
It had a long neck, a relatively short tail, very wide hips and widely-spaced, stocky limbs with five toes on each foot.
“With hips at least 3 feet (1 m) wide and a huge barrel-like ribcage, Savannasaurus elliottorum is the most rotund sauropod we have found so far,” said Dr. Stephen Poropat, from Uppsala University in Sweden and the Australian Age of Dinosaurs Museum in Queensland, Australia, who along with colleagues describes the dinosaur in the Oct. 20 issue of the journal Scientific Reports.
“It lived alongside at least two other types of sauropod, Diamantinasaurus and Wintonotitan, as well as other dinosaurs including ornithopods, armored ankylosaurs, and the carnivorous theropod Australovenator.”
Savannasaurus elliottorum was unearthed in 2005 by David Elliott, co-founder of the Australian Age of Dinosaurs Museum.
The disarticulated skeleton was found within a single siltstone concretion in the Winton Formation, a geological deposit approximately 95 million years old.
After almost 10 years of painstaking work, the hard concretion around the bones was finally removed to reveal one of the most complete Cretaceous sauropod skeletons ever found in Australia.
More excitingly, the remains belonged to a new genus and species of dinosaur.
Savannasaurus elliottorum, holotype specimen: (a–e) dorsal vertebrae; (f) sacrum; (g, h) caudal vertebrae; (i) left coracoid; (j) right sternal plate; (k) left radius; (l) right metacarpal III; (m) left astragalus; (n) coossified right and left pubes; a number of ribs were preserved but have been omitted for clarity. Scale bar - 0.5 m. Image credit: S.F. Poropat et al.
Around 95 million years ago, at the time that Savannasaurus elliottorum was alive, global average temperatures were warmer than they are today. However, it was quite cool at the poles at certain times, which seems to have restricted the movement of sauropods at polar latitudes.
The paleontologists suspect that Savannasaurus elliottorum’s ancestor was from South America, but that it could not and did not enter Australia until 105 million years ago. At this time global average temperatures increased allowing sauropods to traverse landmasses at polar latitudes.
“This pattern of climate-controlled distribution was actually evident in other animals and plants that lived at the same time as Savannasaurus elliottorum during the mid-Cretaceous in Australia,” said co-author Dr. Benjamin Kear, from Uppsala University.
“However, our analysis provides the first compelling evidence that giant herbivorous dinosaurs were subject to these same environmental constraints, and that this signature of periodic trans-polar migration was likely a broader characteristic of Australian faunas and floras from that time.”
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S.F. Poropat et al. 2016. New Australian sauropods shed light on Cretaceous dinosaur palaeobiogeography. Sci. Rep. 6, 34467; doi: 10.1038/srep34467
