Saichania (Mongolian meaning "beautiful one") is a genus of herbivorous ankylosaurid dinosaur from the Late Cretaceous period of Mongolia and China.

[1] The generic name originates from the Mongolian сайхан (saikhan), meaning "beautiful", referring to the pristine state of preservation of the type specimen.

The holotype of Saichania chulsanensis, specimen GI SPS 100/151, was found in a layer of the Barun Goyot Formation, dating from the late Campanian, about seventy-three million years old.

Later, also the juvenile specimen MPC-D 100/1305 was referred and extensively described in 2011, seeming for the first time to provide complete information on the postcranial skeleton.

[2] However, in 2014 Victoria Megan Arbour concluded that the describers had been misled by the skeleton having been completed with a skull cast of GI SPS 100/151, and that the remainder of the fossil belonged to some other ankylosaur, possibly Pinacosaurus.

On the other hand, Arbour added to the number of possible Saichania specimens by referring PIN 3142/250, a skull previously seen as a Tarchia exemplar.

Arbour also considered the Chinese taxa Tianzhenosaurus youngi Pang & Cheng 1998 and Shanxia tianzhenensis Barrett, You, Upchurch & Burton 1998 to be junior synonyms of Saichania.

[3] The referral of PIN 3142/250 to Saichania was contested by Penkalski & Tumanova who considered this specimen to be referable to a new species of Tarchia, T.

[5][6][1] Finds of tail clubs of gigantic individuals suggest larger sizes but their reference to Saichania cannot be substantiated as the holotype, the only specimen sufficiently described, only consists of the front of the animal.

[3] Saichania shared the general ankylosaurid build, being a low-slung, broad, heavily armoured dinosaur, with short forelimbs.

Even for an ankylosaurid however, Saichania is exceptionally robust, its rump strengthened by ossifications and fusions of the vertebral column, ribs, shoulder girdle and breast bones.

The cervical halfrings, protecting the neck, have each an underlying continuous band of bone and the borders between the segments of these rings are covered by extra armour plates entirely hiding these connections from view.

Maryańska presumed it was connected with the underlying premaxillary sinus, allowing the animal to exhale air through the lower hole of the nasal vestibule.

The cervical vertebrae have very long joint processes, zygapophyses, showing that thick intervertebral discs must have been present and that the neck was longer and more flexible than is often assumed.

The short rib and the diapophysis of the first dorsal vertebra are fused with the coracoid, immobilising the entire shoulder girdle relative to the vertebral column.

The breast bones are fully ossified and connect to form a sternal plate that is split in front and broadly forked at the rear.

Thirty centimetres long in the holotype, it has an upper side width of 212 millimetres due to a well-developed inner corner and a strong hatchet-shaped deltopectoral crest.

The segments are connected to an underlying continuous band of bone, mainly by a broad fusion at the front edge, but also by a narrow strip at the rear.

On both sides of this median series, a parallel row of large thin osteoderms is present, featuring moderately high keels, their apexes pointing to behind.

[1] Maryańska classified Saichania as a member of the Ankylosauridae, related to Pinacosaurus and observed that these two dinosaurs differ from all others in the structure of their nasal cavities.

Maryańska provided a differential diagnosis that showed that the two genera were distinct based on morphological differences observed in the bones of the skull and braincase.

[1] Later cladistic analyses recovered a position in the Ankylosaurinae, often close to Tarchia, which is not surprising given that the Operational Taxonomic Unit of the latter was typically based on specimen PIN 3142/250, now referred to Saichania.

[8] Zhejiangosaurus luoyangensis Pinacosaurus grangeri Pinacosaurus mephistocephalus Tsagantegia longicranialis Talarurus plicatospineus Nodocephalosaurus kirtlandensis Saichania chulsanensis Zaraapelta nomadis Tarchia kielanae Ziapelta sanjuanensis Euoplocephalus tutus Ankylosaurus magniventris Anodontosaurus lambei Scolosaurus cutleri Zuul crurivastator Dyoplosaurus acutosquameus The results of an earlier analysis by Arbour & Currie (2015) is reproduced below.