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Genus Rhoetosaurus Longman, 1926 (Род Ретозавр) † - 00826
Species Rhoetosaurus brownei Longman, 1926 †
[Аалениан Баджоциан (средняя юра, 180-175 млн л.н.). Квинсленд (Австралия). Известны несколько частичных скелетов длиной 12-15м.]
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
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.
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).
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
Ссылки - Links
Систематика
http://dinoweb.narod.ru/Eusauropoda.htm
Систематика, описание, история находки (En)
http://home.alphalink.com.au/~dannj/rhoet.htm
Начато: 29.09.2007 Обновлено: 12.10.2007, 12.04.2008, 03.09.2008, 06.2009