Muttaburrasaurus: Beast of the Week

 This week we will be checking out a mysterious plant-eating dinosaur that called what was once Australia home.  Enter Muttaburrasaurus langdoni!

Muttaburrasaurus was a plant-eating dinosaur that lived in what is now Northern Australia during the early to middle Cretaceous period, between 103 and 113 million years ago.  From snout to tail it measured about 23 feet (7m) long.  Its name translate to "Muttaburra Reptile/Lizard" in reference to the part of Queensland in Australia where its fossils were first found. 

Muttaburrasaurus life reconstrucion in watercolors by Christopher DiPiazza.

Muttaburrasaurus would have stood on powerful hind legs, and possessed short but strong arms. It likely normally walked on two legs but would have been capable of dropping down to all fours at times if it wanted.  Scientists were able to predict this not only based on the proportions of its limbs, but also the shape of it's inner ear bones, which often can indicate an animal's posture and preferred head orientation.  

Skeletal mount of Muttaburrasaurus on display at the National Museum of Australia.

Muttaburrasaurus had a relatively long neck and proportionally small head with snout was originally thought to have ended in a tall crest, similar to those of some hadrosaurs, but it was more recently found, thanks to more recently found additional parts of its skull, that it actually had a rather pointed, narrow snout with a bony bulge midway up the nose, making it much more unique looking.  We still don't know the exact purpose of this feature, it probably had something to do with display within the species.  

Remember putting a plastic cup over your mouth as a kid?  It looks like that.

The back of Muttaburrasaurus' jaws were lined with leaf-shaped teeth for slicing through plants.  Unlike its distant relatives, the hadrosaurs, these teeth were arranged in a single row in each jaw with the new replacement teeth growing directly from below.  Muttaburrasaurus also possessed teeth at the very front of its snout, which is actually rare among ornithopod dinosaurs, notably also present in Thescelosaurus. (which it was also maybe more related to?)  Like all ornithopods, the tip of its snout was a beak, which would have been for clipping vegetation. 

Skull of Muttaburrasaurus (missing the tip of the snout) (Photo courtesy of Alcharinga Journal of Paleontology.)

The environment Muttaburrasaurus would have lived in was near an ocean coast and would have been seasonally cold.  This is because during the Cretaceous Australia was much further south and still attached to Antarctica.  Some experts suggest Muttaburrasaurus may have even been adapted to eat plants and algae that grew in salt water, possibly as a food source during the colder months when other plants were more scarce.

Muttaburrasaurus was a member of the ornithopod group of dinosaurs, most famous for including distant relatives like Iguanodon and the "duck-billed" hadrosaurs.  Its identity within this group has proven to be more difficult to pin down.  It was originally considered a close relative of Iguanodon and was even reconstructed with thumb spikes to reflect this. Other experts have since suggested  it was more closely related to dinosaurs like Camptosaurus, and others more to the big-headed rhabdodontid family, like Zalmoxes. (The taxonomy of ornithopod dinosaurs is currently very complicated and tends to change as we discover more fossils.)

References

Bartholomai, Alan and Molnar, R.E. (1981). "Muttaburrasaurus: a new Iguanodontid (Ornithischia:Ornithopoda) dinosaur from the Lower Cretaceous of Queensland". Memoirs of the Queensland Museum. 20 (2): 319–349.

Herne, M. C.; Bevitt, J. J.; Milan, L.; Hocknull, S. A.; Tait, A. M.; Allen, C. M.; Rozefelds, A. C.; Molnar, R. E.; Weisbecker, V.; Bell, P. R. (2026). "Cranial anatomy, palaeoneurology, palaeobiology and stratigraphic age of the large-bodied ornithopod, Muttaburrasaurus langdoni Bartholomai and Molnar, 1981, from the mid-Cretaceous of Australia". PeerJ. 14 e20794.

Molnar, Ralph E. (1996). "Observations on the Australian ornithopod dinosaur, Muttaburrasaurus"". Memoirs of the Queensland Museum. 39 (3): 639–652.