''Yuxisaurus'' (meaning "

Yuxi Yuxi () is a prefecture-level city in the central part of Yunnan province of the People's Republic of China. The administrative center of Yuxi is Hongta District. Yuxi is approximately south of Kunming. Geography Yuxi is located in the center ...

lizard") is an extinct genus of basal

thyreophora Thyreophora ("shield bearers", often known simply as "armored dinosaurs") is a group of armored ornithischian dinosaurs that lived from the Early Jurassic until the end of the Cretaceous. Thyreophorans are characterized by the presence of body ...

n dinosaur from the

Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-J ...

(

Sinemurian In the geologic timescale, the Sinemurian is an age and stage in the Early or Lower Jurassic Epoch or Series. It spans the time between 199.3 ± 2 Ma and 190.8 ± 1.5 Ma (million years ago). The Sinemurian is preceded by the Hettangian and is ...

Toarcian The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian. The Toarcian ...

) Fengjiahe Formation of southwestern

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. The type species is ''Yuxisaurus kopchicki.''

Discovery and naming

''Yuxisaurus'' was first named in a ''

bioRxiv bioRxiv (pronounced "bio-archive") is an open access preprint repository for the biological sciences co-founded by John Inglis and Richard Sever in November 2013. It is hosted by the Cold Spring Harbor Laboratory (CSHL). As preprints, papers h ...

'' preprint released in late 2021, but was not considered valid, due to having not been validly published. The taxon was formally published shortly thereafter, in March 2022. The holotype of the taxon, CVEB 21701, represents a partial skeleton including parts of the skull, several vertebrae, elements of the limbs, and at least 120 osteoderms. The generic name, "''Yuxisaurus''," combines a reference to the type locality in

Yunnan Province Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the C ...

, China, with the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

"sauros," meaning "lizard." The specific name, "''kopchicki''," honors the biologist John J. Kopchick.

Classification

''Yuxisaurus'' was a basal thyreophoran. Depending on the dataset, it may be the sister taxon to the German ''

Emausaurus ''Emausaurus'' is a genus of thyreophoran or armored dinosaur from the Early Jurassic (Early Toarcian). Its fossils have been found in Mecklenburg-Vorpommern, northern Germany. ''Emausaurus'' is the only known Toarcian thyreophoran, as well as th ...

'' or more basal than ''

Scelidosaurus ''Scelidosaurus'' (; with the intended meaning of "limb lizard", from Greek / meaning 'rib of beef' and ''sauros''/ meaning 'lizard')Liddell & Scott (1980). Greek-English Lexicon, Abridged Edition. Oxford University Press, Oxford, UK. is a gen ...

'' and eurypods. The discovery of ''Yuxisaurus'' definitively proves that thyreophorans were present in Asia during the Early Jurassic, as other potential records of Early Jurassic Asian thyreophorans, ''

Bienosaurus ''Bienosaurus'' (meaning "Bien's lizard") is a genus of thyreophoran dinosaur from the Lower Jurassic (probably Sinemurian) Lower Lufeng Formation in Yunnan Province in China. Discovery and species In 1938, Bian Meinian, known in the W ...

'' and ''

Tatisaurus ''Tatisaurus'' is a genus of ornithischian dinosaur from the Early Jurassic from the Lower Lufeng Formation in Yunnan Province in China. Little is known as the remains are fragmentary. The type species is ''T. oehleri''. Discovery and species ...

'', are too fragmentary to be of any significance. Topology 1: Norman dataset Topology 2: Maidment ''et al.'' dataset

References

Thyreophorans Sinemurian first appearances Toarcian extinctions Fossil taxa described in 2022