Many happy returns Rhoetosaurus on your hundredth birthday. This unusual Australian sauropod was named and scientifically described a hundred years ago. Rhoetosaurus (Rhoetosaurus brownei) is not that well known among the general public. Even ardent dinosaur fans struggle to recall it. However, this taxon is extremely important. When described in 1926, it became Australia’s first named dinosaur. In addition, it is the only named pre-Cretaceous sauropod known from Australia.
Its taxonomic affinity within the Sauropoda is uncertain. For example, palaeontologist Gregory S. Paul assigns it to the Cetiosauridae family. Size estimates also vary, body size estimates based on a partial femur and the vertebrae indicate an animal between twelve to fifteen metres in length. Other sources state that this sauropod may have grown to more than eighteen metres in length.
Rhoetosaurus brownei with a human figure for scale. Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Rhoetosaurus brownei – Not an Elephant!
Stockmen mustering horses on a remote station, approximately thirty-five miles (fifty kilometres) north of the small town of Roma (south-western Queensland), found fossil bones weathering out of a shallow gully. They assumed that the bones were from an elephant, a pachyderm that had escaped from a circus. Some of the vertebrae measured more than fifty centimetres long. The station’s manager, Arthur Browne alerted Heber Longman, the director of the Queensland Museum. Longman described Rhoetosaurus and published his work in the journal “Memoirs of the Queensland Museum (1926)”.
The fossils are thought to be around 165 million years old (Middle Jurassic). Subsequently, a joint expedition by Queensland Museum and the University of Queensland visited the site and recovered more bones, including an almost complete right lower hind limb. Rhoetosaurus (pronounced reet-oh-sore-us) fossils probably represent a single individual. The collection of bones collected more than fifty years apart represent one of the most complete specimens of an Australian sauropod.
A study (Nair and Salisbury) set about attempting to clarify the taxonomy. Examination of alternative phylogenetic hypotheses rules out a close relationship between Rhoetosaurus and East Asian Jurassic sauropods. The phylogeny remains unresolved. The lower hind limb of Rhoetosaurus highlights a several anatomical traits differentiating it from other sauropods. For instance, the pes retains four claws, thought to represent a basal trait. Most sauropods have only three claws on each hind foot.
Longman thought that Rhoetosaurus was a camarasaurid. However, this classification has been discounted. Whilst in the absence of further fossils, the taxonomy of Rhoetosaurus brownei remains elusive.
The CollectA Prehistoric Life Rhoetosaurus Model
In 2009, the model manufacturer CollectA introduced a Rhoetosaurus figure. It is part of their not-to-scale Age of Dinosaurs range. The dinosaur is depicted in a rearing pose. It is a rare model. It measures seventeen centimetres tall. The Rhoetosaurus model was designed by the English polymath Anthony Beeson.
A model of the Middle Jurassic sauropod Rhoetosaurus brownei.
To view the CollectA not-to-scale model range: CollectA Age of Dinosaurs.
Mike from Everything Dinosaur commented:
“The Rhoetosaurus fossils are hugely significant. These fossils provide important and thus far, the only information on Australian Jurassic sauropods. By studying these remains palaeontologists can gain a better understanding of sauropod evolution prior to the break-up of Gondwana.”
For prehistoric animal models and figures visit the multi-award-winning Everything Dinosaur website: Dinosaur and Prehistoric Animal Models.
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