Discovery and species
In 1924, Heber Longman, self-trained paleontologist at (and later director of) the Queensland Museum in Brisbane, learned of a large fossil reptile skeleton exposed at the Durham Downs Station near Roma in central Queensland. The station manager, Arthur Browne, forwarded fragments of bone to Longman, and was honoured with the dinosaur's specific name brownei.
The initial collection was of 22 tail vertebrae, including a series of 16 consecutive bones, and other fragmentary hindlimb pieces. Soon after Longman announced the new discovery, he visited the station and arranged for more material of the same skeleton to be sent to the Queensland Museum. These included additional vertebrae from the thoracic area, bits of rib, more caudals and more of the femur and pelvis as well as a cervical vertebra. Further material was collected by Mary Wade and Alan Bartholomai in 1975, and still more by Drs. Tom Rich, Anne Warren, Zhao Xijin, and Ralph Molnar. By 2012, prepared material comprised 40 vertebrae, five partial thoracic ribs, part of the sacrum, fragments of the ilia, an ischium, the left and right pubic bones, and much of the right hind limb (femur, tibia, fibula, astragalus, and pes). More bones are yet to be removed from rock.
Rhoetosaurus is among the best-known sauropods thus far discovered in Australia, as well as for the Jurassic of Gondwana.
Initially Longman, with advice from leading German paleontologist Friedrich von Huene, noted the primitive nature of Rhoetosaurus, and so for a long time, it was called a cetiosaurid. More recently, others have compared it to Shunosaurus, based on similar general age, but without justification. Given its supposed relationship to Shunosaurus, which had a clubbed tail, Rhoetosaurus has also been hypothesized to possess something similar. The form of the nearly complete hind foot ()at least suggests that lies outside the more derived Neosauropoda, but the material needs further study to determine its precise positioning in sauropod evolution.