''Ruyangosaurus'' (

Ruyang County Ruyang County () is a county in the west of Henan province, China, under the jurisdiction of the prefecture-level city of Luoyang. Ruyang County has been the site of several major discoveries of fossilized dinosaur Dinosaurs are a dive ...

lizard) is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

titanosauriform Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located (hence ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

recovered from the

Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...

Haoling Formation The Haoling Formation is a Mesozoic geologic formation in the Ruyang Basin of Henan, Province, central China. Dinosaur remains are among the fossils that have been recovered from the formation. The Haoling Formation was originally treated as par ...

of China. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is ''R. giganteus'', described in

2009 2009 was designated as the International Year of Astronomy by the United Nations to coincide with the 400th anniversary of Galileo Galilei's first known astronomical studies with a telescope and the publication of Astronomia Nova by Joha ...

Lü Junchang Lü Junchang (; 1965 – 9 October 2018) was a Chinese palaeontologist and professor at the Institute of Geology, Chinese Academy of Geological Sciences. An expert on Mesozoic reptiles, he described and named dozens of dinosaur and pterosaur taxa ...

''et al''.

Description

Along with ''

Huanghetitan ''Huanghetitan'' (meaning "Yellow River titan"), is a genus of sauropod dinosaur from the early Cretaceous Period. It was a basal titanosauriformes, titanosauriform which lived in what is now Gansu, China. History The type species, ''Huangh ...

'' and ''

Daxiatitan ''Daxiatitan'' is a genus of sauropod dinosaur known from the Lower Cretaceous of Gansu, China. Its type and only species is ''Daxiatitan binglingi''. It is known from a single partial skeleton consisting of most of the neck and back vertebrae, ...

'', ''Ruyangosaurus'' is among the largest dinosaurs discovered in

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

Asia. In 2016

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology. He is best known for his work and research on theropoda, theropod dinosaurs and his detailed illustrations, both l ...

gave a length of 30 meters (98 ft) and a weight of 50+ tonnes (55 short tons) - making it a 'mega-sauropod'. According to another estimate, ''Ruyangosaurus'' was probably about 35 meters (115 ft) long, as evidenced by its 207 cm long femur and 127 cm long right tibia. In 2020 Molina-Perez and Larramendi gave a lower estimation of 24.8 meters (81.4 ft) and 34 tonnes (37.5 short tons).

Classification

The describers of ''Ruyangosaurus'' assigned it to Andesauridae. However, Andesauridae is not monophyletic and, as such, is no longer used. Comprehensive phylogenetic analyses of Titanosauriformes conducted by Philip Mannion and colleagues in 2013 found ''Ruyangosaurus'' to be in a polytomy with ''

Andesaurus ''Andesaurus'' ( ; "Andes lizard") is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, it would have had a small head on the end of a long neck and a ...

'' and other basal titanosaurs and near-titanosaur somphospondyls, supporting the original description's assertion of phylogenetic proximity of it and ''Andesaurus'', though not the precise taxonomic assignment, with further modifications of the dataset resolving similar conclusions. However, not all phylogenetic analyses have supported its position as a somphospondyl. A phylogenetic dataset following the description of additional material for ''Ruyangosaurus'' to be a non-titanosauriform macronarian, closely related to ''

Yunmenglong ''Yunmenglong'' (meaning "Yunmeng dragon", after the Yunmengshan area where it was found) is an extinct genus of somphospondylan sauropod known from the late Early Cretaceous of Henan Province, central China. Its remains were discovered in the ...

''. The phylogenetic analysis of Mannion ''et al.'' in 2019 incorporated these updated discoveries into their earlier analysis, along with additional new knowledge for other mid-Cretaceous Asian taxa considered close to Titanosauria. They found ''Ruyangosaurus'' to either be close to ''Andesaurus'' as a basal titanosaur when all characters were considered equally important, or in a large clade of early titanosaurs potentially given the name

Euhelopodidae Euhelopodidae is a family of sauropod dinosaurs of disputed membership and affinities, which contains '' Euhelopus'' and its close relatives. Most proposed euhelopodids are from East Asia. Euhelopodidae was first recognized by Carl Wiman in 1929 ...

related to taxa like ''

Yongjinglong ''Yongjinglong'' is an extinct genus of titanosauriform sauropod dinosaur known from the Early Cretaceous of Lanzhou-Minhe Basin of Gansu Province, China. It contains a single species, ''Yongjinglong datangi''. Discovery ''Yongjinglong'' was f ...

'' and ''

Huanghetitan ruyangensis ''Huanghetitan'' (meaning "Yellow River titan"), is a genus of sauropod dinosaur from the early Cretaceous Period. It was a basal titanosauriformes, titanosauriform which lived in what is now Gansu, China. History The type species, ''Huangh ...

''. Two trees of the results are shown below, equal weighting displaying the results of basal titanosauria, and relationships within Euhelopodidae of extended-implied weighting with a mild down-weighting of highly variable characters (k=9).

Habitat

''Ruyangosaurus'' shared its habitat with ''

Xianshanosaurus ''Xianshanosaurus'' () is a genus of sauropod dinosaur from the Early Cretaceous (Aptian-Albian) of the Ruyang Basin in Henan Province, China. Its type and only species is ''Xianshanosaurus shijiagouensis''. It was described in 2009 by a team of ...

'', ''"

" ruyangensis'', ''

'', ''

Luoyanggia ''Luoyanggia'' (meaning "from Luoyang") is a genus of oviraptorid dinosaur known from the Early Cretaceous Haoling Formation of the Ruyang Basin in Henan Province, central China. The type species is ''L. liudianensis''.Lü., J., Xu, L., Jiang, ...

'', and ''

Zhongyuansaurus ''Zhongyuansaurus'' (meaning "Zhongyuan lizard") is an extinct genus of ankylosaurid dinosaurs known from the Early Cretaceous Haoling Formation of what is now Henan Province, China. The genus contains two species, ''Z. luoyangensis'', named in ...

''. The horizon of ''Ruyangosaurus'' was originally described as being of "early

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

" age, but recent work has assigned it an Aptian-Albian Age based on fieldwork and analysis of invertebrate and microfossil assemblages.Xu, L., Pan, Z.C., Wang, Z.H., Zhang, X.L., Jia, S.H., Lü, J.C., Jiang, B.L., 2012. Discovery and significance of the Cretaceous system in Ruyang Basin, Henan Province. Geological Review 58, 601-613.

References

{{Portal bar, Dinosaurs, Paleontology, China Titanosauria Dinosaur genera Aptian dinosaurs Albian dinosaurs Taxa named by Lü Junchang Taxa named by Hailu You Fossil taxa described in 2009 Dinosaurs of China

Description

Classification

Habitat

See also

References