Rhoetosaurus brownei
Longman 1926

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Rhoetosaurus
Colourised Image

Information
PRONOUNCED
    Ree-toe-saw-rus
MEANING
    Rhoetos (from a Greek myth) reptile
CLASSIFICATION
    ?Cetiosaurinae, Sauropoda, Sauropodomorpha
AGE
    Middle Jurassic (Bajocian?) 175-180 MYA
FORMATION
    Injune Creek Beds (?Hutton Sandstone)
SIZE
    18 metres (59 feet) long, 4 metres (13 feet) at hip
LOCATION
    Roma, Queensland

Rhoetosaurus was discovered on Durham Downs Station near the town of Roma in Queensland in 1924. The station manager, Mr Arthur Browne, forwarded some fossil bone fragments to the Museum of Queensland where they were confirmed as a new dinosaur species. The material included some caudal vertebrae and other fragments. In March 1926 the then director of the Queensland Museum, Dr Heber Longman described the bones as a sauropod dinosaur and named it Rhoetosaurus brownei, after the giant Rhoetos in Greek mythology. He visited the site in May of that year and took back another ton of fossil material and rock. The additional material included a partial hind leg, pelvic elements, tail vertebrae, thorasic vertebrae, ribs and one partial cervical vertebra. In 1975 Dr Mary Wade revisited the site and uncovered more of the skeleton. Since then another excavation has uncovered more bones including a nearly complete hind foot.


Click image above. Recovered bones are dark

Rhoetosaurus is one of the earliest known sauropods, dating to the Middle Jurassic. Its lack of specialised features and its fragmentary nature makes its exact classification difficult. It is only one of two well known sauropods from Australia, the other being Austrosaurus Mackillopi from the Early Cretaceous. A single isolated partial neck vertebra may also be evidence of a brachiosaur. All of these sauropod remains have been found in Queensland with little anywhere else in the country. So far Rhoetosaurus remains the largest Australian dinosaur known, the femur alone measuring 1.5 metres (5 feet) in length.

The single cervical vertebra is elongated and seems to indicate that Rhoetosaurus had quite a long neck. Initially classified as being akin to Camarasaurus supremus by Longman, it has since been placed in the Cetiosaurinae. This group may not be a natural grouping and may be a collection of odds and ends that do not fit anywhere else, a bit like the Ornithocheiridae family of pterosaurs. More recently it has been suggested that Rhoetosaurus may belong with the Euhelopodid sauropods (more specificially Shunosaurs) based on supposed forked chevrons observed on the tail vertebrae.

This reconstruction is based on the latest research into Rhoetosaurus. The neck is elongated (according to the length of the individual cervical vertebrae), and the tail tapers quickly. Given that there may be some similarities with euhelopodid sauropods, and when the robust nature of the tail vertebrae are taken into consideration, it may be possible that Rhoetosaurus bore some sort of spiked tail club like the Chinese Shunosaurus. In the absence of such a structure in the fossil record, however, I have not included one here. I have made the head unashamedly euhelopodid, since the general form tended to lie somewhere in the middle of the range of sauropod possibilities (from the deeply arched skulls of Brachiosaurus or Camarasaurus to the low elongated skulls of diplodocids).

Rhoetosaurus femur Rhoetosaurus hind foot
The femur and hind foot of Rhoetosaurus (not at the same scale). The femur measures about 1.5 metres long

Longman, H.A. 1926 A giant dinosaur from Durham Downs, Queensland. Memoirs of the Queensland Museum 8:183-194.

Longman, H.A. 1927 The giant dinosaur Rhoetosaurus brownei. Memoirs of the Queensland Museum 9:1-18


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