Muttaburrasaurus

*Muttaburrasaurus langdoni*

* Jurassic Park Institute Artwork
* Timothy Bradley Artwork
* Robert F Walters Artwork

***Muttaburrasaurus*** was a plant-eating dinosaur that lived during the middle Cretaceous period, about 113-97.5 million years ago. The name means "Muttaburra (in Queensland, Australia) lizard". *Muttaburrasaurus* was about 24 feet long, weighed about 3.1 short tons, and had a fat bump on its nose. They may have lived in herds.

## Description

*Muttaburrasaurus* was about 26ft and weighed around 3.1 short tons.

*Muttaburrasaurus* could move on both 2 legs and 4 legs. The three middle digits of the front limbs were joined and formed a hoof-like pad to walk. Molnar first rebuilt *Muttaburrasaurus* with a thumb spike, but later doubted it had one. The foot was long and broad, with four toes.

The skull of *Muttaburrasaurus* was flat, with a triangular cross-section seen from the top, the back of the head was broad but the snout pointed. The snout had the form of a large, hollow, upward-cruved snout that might have been used to make calls or for display. But, as no fossilised nasal tissue has been found, this is still conjectural. This so-called *bulla nasalis* was shorter with the older *Muttaburrasaurus* sp., as is shown by the *Dunluce Skull*. The top part of the *bulla* of the holotype has not been preserved, but at least the second skull has a round form.

## History

The species was first described from a partial skeleton found by Doug Langdon in 1963 at Rosebery Downs Station next to Thomson River near Muttaburra, Queensland, Australia, hence the creature's name. The remains were found by paleontologist Dr Alan Bartholomai and entomologist Edward Dahms. After a long preparation of the fossils, it was named in 1981 by Bartholomai and Ralph Molnar, who honored its discoverer with its specific name *langdoni*.

The holotype, specimen **QM F6140**, was found in the Mackunda Formation. It's made up of a partial skeleton with skull and lower jaws. The bottom of the skull and the back of the jawbone, lots of vertebrae, parts of the pelvis, and parts of the front and hind limbs have been preserved.

Some teeth have been found further north, near Hughenden, and south at Lightning Ridge, in northwestern New South Wales. At Lightning Ridge there have been found teeth and a shoulder blade that may be from a *Muttaburrasaurus*. A skull, known as the "Dunluce Skull", specimen QM F14921, was found by John Stewart-Moore and 14 year old Robert Walker on Dunluce Station, between Hughenden and Richmond in 1987. It comes was thought by Molnar to be a separate, yet unnamed species, a *Muttaburrasaurus* sp. The same place had two incomplete skeletons in 1989. There have also been isolated teeth and bones found at Iona Station southeast of Hughenden.

## Paleobiology

*Muttaburrasaurus* had strong jaws with sharp teeth. Unlike most dinosaurs, *Muttaburrasaurus* replaced its teeth all at once. It lacked a first ridge on the teeth sides, showing eleven lower ridges. In 1981 Molnar thought that these traits might mean *Muttaburrasaurus* was an omnivore, at times eating carcasses. In 1995 he changed his view, comparing them to the ceratopsian shearing teeth system. They would have been used to eat tough plants such as cycads.

## Classification

Molnar first assigned *Muttaburrasaurus* to the Iguanodontidae, but in 2010, a study by Andrew McDonald placed it in the Rhabdodontidae.

## JPInstitute.com Description

Muttaburrasaurus was a member of the same dinosaur family as Iguanodon. It was a medium-sized, plant-eating dinosaur that roamed what is now Australia. It had a large bump on its nose that may have been used to amplify the sounds it made so it could be heard at great distances.

Muttaburrasaurus was a very typical member of the iguanodontia, and it seems to be very closely related to Camptosaurus. Its teeth were a bit different from those of other iguanodonts, as they were seemingly designed for cutting.

## Dinosaur Field Guide Description

Muttaburrasaurus ("lizard from Muttaburra") has a stocky, well-muscled body. Although the only mounted skeleton in the world is shown with a thumb spike as big as Iguanodon's, some scientists question the restoration of this feature. That's because the original "spike" bone in Muttaburrasaurus is only partially preserved. One feature Muttaburrasaurus has in common with later ornithopods, or two-legged plant-eating dinosaurs, is its large nose. It is not known if this nose allowed Muttaburrasaurus to communicate, as the hadrosaurs are believed to have done. The nose is closer to the tip of the snout than in hadrosaurs, but it is still large enough to block any stereoscopic vision directly ahead. Humans and predators have stereoscopic vision, which allows them to see in depth. Plant-eating dinosaurs and other prey have non-overlapping fields of vision, which gives them the ability to see more widely but hinders depth perception.

### Fun Facts

Because this dinosaur cannot be confidently placed within any known ornithopod family, it is considered a "free agent" (like an unsigned football player)

### Trivia

The original specimen of Muttaburrasaurus was found in marine rocks. The dinosaur's body may have floated out to sea before fossilization.

## Links

http://web.archive.org/web/20030405114030fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_mutta.html

## References

1. ↑ Paul, G.S. (2010). *The Princeton Field Guide to Dinosaurs*, Princeton University Press, p. 286.
2. ↑ 2.0 2.1 2.2 2.3 2.4 Template:Cite journal
3. ↑ Template:Cite journal
4. ↑ Molnar, R.E., 1995, "Possible convergence in the jaw mechanisms of ceratopians and *Muttaburrasaurus*". In: A.Sun and Y.Wang (eds) *Sixth Symposium on Mesozoic Terrestrial Ecosystems and Biota, short papers*. China Ocean Press, Beijing. pp.115-117