Despite the age of dinosaurs having passed more than 65 million years ago, and with it the plethora of giant long-necked dinosaurs called sauropods whose titanic sizes seem unthinkable in our day and age, we should probably count ourselves lucky that we live alongside the current title-holder for the largest animal to have ever lived on Earth. The blue whale (Balaenoptera musculus ssp. Intermedia) reaches a length of 98 ft (29.87 m) and a weight of 400,000 lbs (181,436 kg). A blue whale’s heart is said to be as large as a small car; it even tries to double it up by also holding the title of the loudest animal on Earth, with its calls reaching a truly deafening 188 decibels. The blue whale’s sheer size, however, is enabled by its own buoyancy—helped in part by the very waters it swims through during its daily search for around 7,936 lbs (3,600 kg) of krill for food. That’s not to sell sauropods short, though; it’s impressive how those reptiles reached such massive sizes without any water around their bodies to help lift their weight as they moved across the landscape.
Sauropods, members of the reptilian clade Sauropoda, were a group of reptiles well-known for their herbivory, long necks, and massive sizes. Coined by American professor of paleontology Othniel Charles Marsh back in 1878, the term “sauropod” is derived from Greek, and roughly translates to “lizard foot.” Sauropod fossils can be found on all continents—even Antarctica—as these animals evolved and started to spread before the split of the supercontinent Pangaea during the Early Jurassic period, around 200 million years ago. While North American sauropods like Brontosaurus and Brachiosaurus were made more famous by place of discovery or pop culture, the most massive of them were mostly found in South America. The largest discovered so far, by evidence, was the Argentinosaurus, weighing from 65 to 80 metric tons (143,000 to 176,000 lbs, 65,000 to 80,000 kg), and growing to lengths of 30 to 40 m (100 to 130 ft). And just this year, Australia seems to have added itself to the list of places of interest for those searching for the largest of the dinosaurs.
In a study done by researchers from the Eromanga Natural History Museum (ENHM) and the Queensland Museum and published in PeerJ, a 2007 find of a specimen of the sauropod Australotitan cooperensis, nicknamed “Cooper,” determined it to be the largest dinosaur ever discovered in the continent, measuring up to a length of 25 to 30 m (82 to 98 ft) and a height of 5 to 6.5 m (16.4 to 21.3 ft). Derived from Greek for “southern titan,” the giant plant-eater walked the Earth some 90 million years ago during the Cretaceous period, the last of the three-part act of the so-called “Age of Reptiles.” The “Age of Reptiles” often describes the Mesozoic era, a segment of geologic time subdivided into three periods: the Triassic, the Jurassic (where the famous Jurassic Park media franchise gets its name), and the Cretaceous period. “Cooper” belonged to a group of sauropods called titanosaurs, the last surviving group of sauropods whose members lived up until the asteroid impact that wiped non-avian dinosaurs—as well as more than 75% of all species alive on Earth at the time—off the planet some 65 million years ago. The largest of the titanosaurs was the aforementioned Argentinosaurus; the largest titanosaurs found so far have been found in South America, making this Australian titanosaur find all the more unique.
According to ENHM co-founder Robyn Mackenzie, the team was able to quickly establish the size of the specimen from the sheer size of the bone fragments, and that they “were able to measure the bones and compare them with other species in Australia and the rest of the world.” While several of the large pieces of what remains of its skeleton remained intact, including shoulder blades and limbs, the team faced delays in identifying the species due to issues with handling the large, fragile fossils. The sizes of the fossils meant that pieces of the skeleton had to be sent to different institutions, sometimes hundreds of miles apart.
Scanned by 3D technologies, the team analyzed each bone of the specimen and compared what they found to bones of similar species also found on the continent. This allowed them to determine the identity of “Cooper” and finalized its standing as the largest dinosaur ever discovered in Australia. Mackenzie notes that this “puts Australia on the map,” as the largest of these titanosaurs have only been found in South America so far. Said Mackenzie: “This is just the tip of the iceberg for discoveries in Australia. […] It has opened up a whole new dinosaur frontier.”
Bibliography
- Sood, A. (2021, June 8). Scientists confirm discovery of Australia’s largest dinosaur, two stories tall and a basketball court long. CNN. Retrieved August 26, 2021, from https://edition.cnn.com/2021/06/08/australia/australia-dinosaur-largest-discovery-intl-hnk-scn/index.html
- Hocknull, S.A., Wilkinson, M., Lawrence, R.A., Konstantinov, V., Mackenzie, S., Mackenzie, R. (2021). A new giant sauropod, Australotitan cooperensisgen. et sp. nov., from the mid-Cretaceous of Australia. PeerJ 9:e11317 https://doi.org/10.7717/peerj.11317
