Titans once lived in what is now Australia. After years of research, paleontologists have described the fossils of a titanosaur. It is the largest known dinosaur that has ever stamped in Australia. The new species is Australotitan baptized by a team that described the fossils in science journal Tuesday PeerJ.
Titanosaurs were the most successful long-necked dinosaurs (sauropods) of the dinosaur age. The diversity in this group was enormous. There were small giants, no heavier than modern elephants, as well as behemoths with a length of more than 30 meters and a weight of 50 tons, comparable to large whales. Titanosaurs are the largest land animals that have ever lived.
Australotitan lived 95 million years ago. Australia was then still connected to Antarctica.
The first Australotitan fossils were discovered as early as 2005 on the land of a family of sheep farmers in the dry Queensland Outback near the village of Eromanga (pop. 119). Sandy Mackenzie, then 14, first found a fossil on the site in 2004. His parents Robyn and Stuart Mackenzie subsequently established a natural history museum in Eromanga.
Had a lot to endure
The fossil was nicknamed “Cooper” because the remains were in the basin of the Cooper Creek river.
As of 2007, Australotitan fossils were seriously excavated. Paleontologists found, among other things, a shoulder blade, both humerus, two pieces of femur and parts of the hip.
The fossils and rocks in this area are brought to the surface by the expansion and contraction of clay-rich soil (vertisol). As a result, the bones have had to endure a lot. The rock is broken on the way up. And once on the surface, the bones are sandblasted by dry wind. Traces of wombats, small marsupials, have also been found in the area. They may also have played a role in working up the bones.
In addition to remains of Australotitan, the team also found a trampled bottom full of fossil traces of long-necked dinosaurs. The animals walked in a column one after the other, according to the tracks. There were also fossil ferns, conifers and petrified wood in the area.
Reliable body weight
The investigation took more than ten years. This is partly because all of the Australotitan bones found were scanned with CT scanners. Quite an undertaking: some bones weigh hundreds of kilograms and had to be transported over great distances.
With long-necked dinosaurs, the question is always: how big was he? The researchers resisted the temptation to make an estimate, they write. There is much debate among paleontologists whether you can extrapolate a reliable body weight from a fragmentary skeleton. Attempts to do so often yield results with great uncertainty, sometimes with a difference of a factor of three. Titanosaurs with similar bones to Australotitan have been estimated to have masses of 23 to 74 tons.
The paleontologists didn’t need that estimate for the study either: it’s clear that Australotitan differs from other longnecks found in Australia. Australotitan is clearly the largest, but its shoulder blade is remarkably gracefully built for a long neck of this size.
A version of this article also appeared in NRC Handelsblad on 9 June 2021
A version of this article also appeared in NRC in the morning of June 9, 2021