The Chinese colossus: an evaluation of the phylogeny of Ruyangosaurus giganteus and its implications for titanosaur evolution
- Published
- Accepted
- Subject Areas
- Biogeography, Paleontology, Taxonomy
- Keywords
- Ruyangosaurus, Titanosauria, China, Sauropods, Biggest dinosaur
- Copyright
- © 2017 Sassani et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2017. The Chinese colossus: an evaluation of the phylogeny of Ruyangosaurus giganteus and its implications for titanosaur evolution. PeerJ Preprints 5:e2988v1 https://doi.org/10.7287/peerj.preprints.2988v1
Abstract
For many years the precise taxonomy of Titanosauria has been a puzzle, and even today only certain segments of this vast clade are well-understood. The phylogenetic positions of many titanosaurs are murky, though specimens often still await rigorous analysis. One of the largest examples is the massive Chinese titanosaur Ruyangosaurus giganteus – though largely incomplete, the holotype is distinct enough to indicate strong phylogenetic affinities with a specific subgroup of titanosaurs. A review of previous literature on Ruyangosaurus, referred tentatively to Andesauridae, shows that this classification is based on three weak, non-diagnostic characters. Ruyangosaurus differs from taxa traditionally included in Andesauridae in at least 20 characters of the torso, femur, and tibia. Several plesiomorphies of Ruyangosaurus are extremely rare in titanosauria except for the clade Lognkosauria and its close relatives. The vertebra initially described as a posterior cervical is most likely an anterior dorsal, with a strong resemblance to that of Puertasaurus. The posterior dorsal of Ruyangosaurus shares synapomorphies with Mendozasaurus and Dreadnoughtus. The femur clusters close to the femora of Malawisaurus, Traukutitan, and Pitekunsaurus. Ruyangosaurus is here recovered as a lognkosaurian, with significant implications for the distribution and evolution of that group and the paleobiology of Mid-Cretaceous China.
Author Comment
This paper comments on the affinities of the poorly known Chinese taxon Ruyangosaurus giganteus and its affinities to the mainly South American clade Lognkosauria. This is a draft manuscript, uploaded to receive any comments, qestions, guidance, etc. to improve the manuscript before submission for formal peer review takes place.