Savannasaurus

Savannasaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous of Queensland, Australia, containing one species, Savannasaurus elliottorum, named in 2016 by Poropat et al.[1] The only known specimen was originally nicknamed "Wade".[2][3] The holotype is held on display at the Australian Age of Dinosaurs museum.

Savannasaurus
Temporal range: Cenomanian-Turonian
~93.9 Ma
Savannasaurus skeleton
Skeleton
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Clade: Sauropoda
Clade: Titanosauria
Genus: Savannasaurus
Poropat et al. 2016
Species:
S. elliottorum
Binomial name
Savannasaurus elliottorum
Poropat et al. 2016

Description

Savannasaurus was a medium-sized titanosaur about 15 metres (49 ft) in length.[3] The sacrum and the fused ischium-pubis complex are both over one metre in width at their narrowest points, making Savannasaurus an unusually wide-bodied titanosaur. In addition to this, the describers identified several other distinguishing characteristics: the first few caudal vertebrae have shallow pits, or fossae, in their sides, a feature that was previously only known among brachiosaurids; the edges of the sternal plates are straight, not kidney-shaped like other titanosaurs; the end of the fourth metacarpal is hourglass-shaped; there is a ridge on the side of the pubis extending forward and downward from the obturator foramen; and the astragalus is taller than it is wide or long.[1]

As with other titanosauriforms, the internal texture of the vertebrae is pneumatized by many small holes (camellate), and the dorsal ribs also bear pneumatic cavities. The dorsal vertebrae have ridges on the sides of their bottom faces as in Diamantinasaurus and Opisthocoelicaudia, but Savannasaurus lacks the keel on the bottom of the dorsal vertebrae as in these species; the dorsal neural spines are also not split into two, unlike Opisthocoelicaudia. The known cervical vertebrae and dorsal vertebrae are opisthocoelous, while all of the caudal vertebrae are amphicoelous unlike most other titanosaurs.[1]

Discovery and naming

Savannasaurus
Holotype skeleton as found

The holotype specimen of Savannasaurus, AODF 660, was discovered in 2005 on the Belmont sheep station by David Elliot, founder of Australian Age of Dinosaurs. The Belmont sheep station, northeast of Winton, Queensland, is part of the upper Winton Formation which has been dated to the Cenomanian-Turonian (93.9 mya) based on detritial zircons.[4] One of the holotype's metatarsals was originally thought to have belonged to a theropod, but later excavations revealed the remainder of the skeleton.[3] The specimen consists of several cervical, dorsal, sacral, and caudal vertebrae, several ribs, portions of the shoulder girdle including a coracoid and both sternal plates, parts of the forelimbs including the feet, several elements of the hip, and bones from the hind foot, along with various fragments. The specimen was encased in a single concretion.[1]

The genus name of Savannasaurus, from Spanish zavana ("savanna"), refers to the environment in which it was found. The species name honours the Elliott family and their contributions to Australian palaeontology.[1]

Phylogeny

A phylogenetic analysis conducted in 2016 found Savannasaurus to be closely related to the contemporaneous Diamantinasaurus, as a non-lithostrotian titanosaur.[1]

Titanosauria

Andesaurus

Dongyangosaurus

Baotianmansaurus

Ligabuesaurus

Savannasaurus

Diamantinasaurus

Xianshanosaurus

Daxiatitan

Lithostrotia

Malawisaurus

Muyelensaurus

Futalognkosaurus

Epachthosaurus

Nemegtosauridae

Tapuiasaurus

Nemegtosaurus

Isisaurus

Saltasauridae

Saltasaurus

Opisthocoelicaudia

Jiangshanosaurus

Alamosaurus

Paleoecology

Savannasaurus lived alongside a diverse vertebrate fauna in the upper Winton Formation,[4] that included its close relative Diamantinasaurus, other sauropods Wintonotitan and Austrosaurus, the megaraptoran theropod Australovenator, ankylosaurians, and hypsilophodonts, along with the lungfish Metaceratodus, turtles, the crocodilian Isisfordia, and pterosaurs. The environment it lived in would have been populated by plants such as ferns, ginkgoes, gymnosperms, and angiosperms.[5]

See also

References

  1. ^ a b c d e f Poropat, S.F.; Mannion, P.D.; Upchurch, P.; Hocknull, S.A.; Kear, B.P.; Kundrát, M.; Tischler, T.R.; Sloan, T.; Sinapius, G.H.K.; Elliott, J.A.; Elliott, D.A. (2016). "New Australian sauropods shed light on Cretaceous dinosaur palaeobiogeography". Scientific Reports. 6: 34467. doi:10.1038/srep34467. PMC 5072287. PMID 27763598.
  2. ^ St. Fleur, Nicholas (20 October 2016). "Meet the New Titanosaur. You Can Call It Wade". New York Times. Retrieved 21 October 2016.
  3. ^ a b c Geggel, Laura (2016). "Wide-Hipped Dinosaur the Size of a Bus Once Trod Across Australia". Live Science. Purch.
  4. ^ a b Tucker, R.T.; Roberts, E.M.; Hu, Y.; Kemp, A.I.S.; Salisbury, S.W. (2013). "Detrital zircon age constraints for the Winton Formation, Queensland: Contextualizing Australia's Late Cretaceous dinosaur faunas". Gondwana Research. 24 (2): 767–779. doi:10.1016/j.gr.2012.12.009.
  5. ^ Hocknull, Scott A.; White, Matt A.; Tischler, Travis R.; Cook, Alex G.; Calleja, Naomi D.; Sloan, Trish; Elliott, David A. (2009). Sereno, Paul (ed.). "New Mid-Cretaceous (Latest Albian) Dinosaurs from Winton, Queensland, Australia". PLoS ONE. 4 (7): e6190. doi:10.1371/journal.pone.0006190. PMC 2703565. PMID 19584929.
Apatosaurinae

Apatosaurinae is the name of a subfamily of diplodocid sauropods that existed between 157 and 150 million years ago in North America. The group includes two genera for certain, Apatosaurus and Brontosaurus, with at least five species. Atlantosaurus and Amphicoelias might also belong to this group.Below is a cladogram of apatosaurinae interrelationships based on Tschopp et al., 2015.

Brasilotitan

Brasilotitan is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous (early Maastrichtian) Adamantina Formation of Brazil. The type species is Brasilotitan nemophagus.

Cetiosauridae

Cetiosauridae is a family of sauropod dinosaurs. While traditionally a wastebasket taxon containing various unrelated species, some recent studies have found that it may represent a natural clade. Additionally, at least one study has suggested that the mamenchisaurids may represent a sub-group of the cetiosaurids, which would be termed Mamenchisaurinae.

Diamantinasaurus

Diamantinasaurus is an extinct genus of non-lithostrotian titanosaurian sauropod from Australia that lived during the early Late Cretaceous, about 94 million years ago. The type species of the genus is D. matildae, first described and named in 2009 by Scott Hocknull and colleagues. Meaning "Diamantina lizard", the name is derived from the location of the nearby Diamantina River and the Greek word sauros, "lizard". The specific epithet is from the Australian song Waltzing Matilda, also the locality of the holotype and paratype. The known skeleton includes most of the forelimb, shoulder girdle, pelvis, hindlimb and ribs of the holotype, and one shoulder bone, a radius and some vertebrae of the paratype.

Diplodocinae

Diplodocinae is an extinct subfamily of diplodocid sauropods that existed from the Late Jurassic to Early Cretaceous of North America, Europe and South America, about 161.2 to 136.4 million years ago. Genera within the subfamily include Tornieria, Supersaurus, Leinkupal, Galeamopus, Diplodocus, Kaatedocus and Barosaurus.Cladogram of the Diplodocidae after Tschopp, Mateus, and Benson (2015).

Eomamenchisaurus

Eomamenchisaurus (meaning "dawn Mamenchisaurus") is a genus of mamenchisaurid sauropod dinosaur from the Middle Jurassic of Yuanmou, Yunnan, China. The type species is E. yuanmouensis, described by Lü Junchang et al. in 2008.

Ferganasaurus

Ferganasaurus was a genus of dinosaur first formally described in 2003 by Alifanov and Averianov. The type species is Ferganasaurus verzilini. It was a sauropod similar to Rhoetosaurus. The fossils were discovered in 1966 in Kyrgyzstan from the Balabansai Formation and date to the Callovian stage of the Middle Jurassic.

Flagellicaudata

Flagellicaudata is a clade of Dinosauria. It belongs to Sauropoda and includes two families, the Dicraeosauridae and the Diplodocidae.

Gravisauria

Gravisauria is a clade of sauropod dinosaurs consisting of some genera, Vulcanodontidae and Eusauropoda.

Huangshanlong

Huangshanlong is a genus of mamenchisaurid dinosaurs native to the Anhui province of China. It contains a single species, Huangshanlong anhuiensis. H. anhuiensis represents, along with Anhuilong and Wannanosaurus, one of three dinosaurs fround in Anhui province.

Jiutaisaurus

Jiutaisaurus is a genus of sauropod dinosaur from the Quantou Formation of China. Jiutaisaurus was a sauropod which lived during the Cretaceous. The type species, Jiutaisaurus xidiensis, was described by Wu et al. in 2006, and is based on eighteen vertebrae.

Kaijutitan

Kaijutitan (meaning "Kaiju titan" after the type of Japanese movie monsters) is a genus of basal titanosaur dinosaur from the Sierra Barrosa Formation from Neuquén Province in Argentina. The type and only species is Kaijutitan maui.

Lithostrotia

Lithostrotia is a clade of derived titanosaur sauropods that lived during the Early Cretaceous and Late Cretaceous. The group was defined by Unchurch et al. in 2004 as the most recent common ancestor of Malawisaurus and Saltasaurus and all the descendants of that ancestor. Lithostrotia is derived from the Ancient Greek lithostros, meaning "inlaid with stones", referring to the fact that many known lithostrotians are preserved with osteoderms. However, osteoderms are not a distinguishing feature of the group, as the two noted by Unchurch et al. include caudal vertebrae with strongly concave front faces (procoely), although the farthest vertebrae are not procoelous.

Microcoelus

Microcoelus is a dubius genus of small Titanosaurian sauropod dinosaur native to Argentina. It is known from only a single dorsal vertebra. A left humerus was formerly referred to this species, but it is now considered to belong to Neuquensaurus. This species may be a synonym of the contemporary sauropod Neuquensaurus australis.It was described by British paleontologist Richard Lydekker in 1893.

Pilmatueia

Pilmatueia is a diplodocoid sauropod belonging to the family Dicraeosauridae that lived in Argentina during the Early Cretaceous.

Ruyangosaurus

Ruyangosaurus (Ruyang County lizard) is a genus of titanosauriform sauropod dinosaur recovered from the Early Cretaceous Haoling Formation of China. The type species is R. giganteus, described in 2009 by Lü Junchang et al. Along with Huanghetitan and Daxiatitan, Ruyangosaurus is among the largest dinosaurs discovered in Cretaceous Asia.

Tambatitanis

Tambatitanis is an extinct genus of titanosauriform dinosaur from the Early Cretaceous (probably early Albian) of Japan. It is known from a single type species, Tambatitanis amicitiae. It was probably around 14 meters long and its mass was estimated at some 4 tonnes. It was a basal titanosauriform and possibly belonged to the Euhelopodidae.

Tastavinsaurus

Tastavinsaurus is a genus of sauropod dinosaur belonging to the Titanosauriformes. It is based on a partial skeleton from the Early Cretaceous of Spain. The type species is Tastavinsaurus sanzi, named in honor of the Rio Tastavins in Spain and Spanish paleontologist José Luis Sanz.

Vulcanodontidae

The Early Jurassic sauropod dinosaurs Zizhongosaurus, Barapasaurus, Tazoudasaurus, and Vulcanodon may form a natural group of basal sauropods called the Vulcanodontidae. Basal vulcanodonts include some of the earliest known examples of sauropods. The family-level name Vulcanodontidae was erected by M.R. Cooper in 1984. In 1995 Hunt et al. published the opinion that the family is synonymous with the Barapasauridae. One of the key morphological features specific to the family is an unusually narrow sacrum.

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