Diamantinasaurus: Beast of the Week

This week we'll be learning about a beast that greatly helps us understand how sauropod dinosaurs ("long-necks") looked and lived.  Check out Diamantinasaurus matildae!

Diamantinasaurus lived in what is now Queensland, Australia during the middle Cretaceous period, between 95 and 92 million years ago.  It's considered medium-sized for a sauropod, and would have measured about 52 feet (16m) long from snout to tail. (Yes. 52 feet is only medium for sauropods!) Like all sauropods it would have eaten plants when alive.  It's genus name is after the Diamantina River, near where its bones were initially discovered.  The species name is after the popular Australian song, "Waltzing Matilda".

Watercolor reconstruction of Diamantinasaurus by Christopher DiPiazza.  Fossil evidence shows this dinosaur wasn't a picky eater, eating a wide variety of plants.

Diamantinasaurus was initially known from limb bones, ribs, and pelvis bones.  It's limbs stand out as being particularly robust, even for a sauropod.  Another interesting feature is the fact that its front limbs possessed short little finger bones and a single large claw on each hand.  These are common traits to most sauropods from earlier times, but were lost in most later sauropods that lived during the Cretaceous period. Diamantinasaurus appears to have retained what is otherwise considered this primitive trait.  

Photograph of the bones in Diamantinasaurus' manus(hand).  Note the prominent claw that grew out of the side of the hand.

Later on after its initial discovery Diamantinasaurus' skull was discovered.  This is exciting since the skulls of sauropods notoriously are hard to find. (they appear to have tended to get separated from the rest of the body and destroyed before fossilization, which makes sense how small they are compared to the bodies) Diamantinasaurus' snout sloped downwards, and actually resembles the skull of Brachiosaurus, even thought it is believed to have been more closely related to fellow Cretaceous sauropods, like Saltasaurus.  A few of Diamantinasaurus' teeth were also found still in the jaw that had not grown in yet, which were narrow and rod-shaped with chisel-like tips.  

Front and side view of the skull of Diamantinasaurus.

More recently in 2025, fossilized gut contents of Diamantinasaurus were discovered.  This is amazing since up until this point, even though everyone assumed sauropods ate plants, actual proof in the form of a fossilized last meal had never been found in one.  As it turns out Diamantinasaurus appears to have been a generalist plant-eater, with remains of all sorts of plants, including ferns, pine trees, and flowering plants found in its stomach.  This means Diamantinasaurus wasn't only feeding at the tops of trees, like sauropods are often depicted doing, but rather was using its long neck to reach all sorts of heights to feed.  Like all sauropods, Diamantinasaurus couldn't chew since its teeth were only at the front of its snout for chomping.  Rather it would have swallowed mouthfuls of plants whole and relied likely on fermentation inside its body to digest the meals.  Some believe that sauropods also could have swallowed stones to help aid in digestion, like some birds and other reptiles are known to do today.

References

Poropat, S.F.; Upchurch, P.; Mannion, P.D.; Hocknull, S.A.; Kear, B.P.; Sloan, T.; Sinapius, G.H.K.; Elliot, D.A. (2014). "Revision of the sauropod dinosaur Diamantinasaurus matildae Hocknull et al. 2009 from the mid-Cretaceous of Australia: Implications for Gondwanan titanosauriform dispersal". Gondwana Research. 27 (3): 995–1033.

Poropat, Stephen F; Kundrát, Martin; Mannion, Philip D; Upchurch, Paul; Tischler, Travis R; Elliott, David A (2021-01-20). "Second specimen of the Late Cretaceous Australian sauropod dinosaur Diamantinasaurus matildae provides new anatomical information on the skull and neck of early titanosaurs". Zoological Journal of the Linnean Society. 192 (2): 610–674.

Poropat, S.F.; Mannion, P.D.; Upchurch, P.; Hocknull, S.A.; Kear, B.P.; Kundrát, M.; Tischler, T.R.; Sloan, T.; Sinapius, G.H.K.; Elliott, J.A.; Elliott, D.A. (2016). "New Australian sauropods shed light on Cretaceous dinosaur palaeobiogeography". Scientific Reports. 6 34467.

Poropat, S. F.; Tosolini, A.-M. P.; Beeston, S. L.; Enchelmaier, M. J.; Pentland, A. H.; Mannion, P. D.; Upchurch, P.; Chin, K.; Korasidis, V. A.; Bell, P. R.; Enriquez, N. J.; Holman, A. I.; Brosnan, L. M.; Elson, A. L.; Tripp, M.; Scarlett, A. G.; Godel, B.; Madden, R. H. C.; Rickard, W. D. A.; Bevitt, J. J.; Tischler, T. R.; Croxford, T. L. M.; Sloan, T.; Elliott, D. A.; Grice, K. (2025). "Fossilized gut contents elucidate the feeding habits of sauropod dinosaurs". Current Biology. 35 (11): 2597–2613.