''Yizhousaurus'' (meaning "Yizhou lizard", after the Chuxiong Yi Autonomous Region) 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 ...

of basal

sauropodiform Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct clade of long-necked, herbivorous, saurischian dinosaurs that includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had lon ...

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 ...

s which existed in what is now

Lufeng Formation The Lufeng Formation (formerly Lower Lufeng Series) is a Lower Jurassic sedimentary rock formation found in Yunnan, China. It has two units: the lower Dull Purplish Beds/Shawan Member are of Hettangian age, and Dark Red Beds/Zhangjia'ao Member a ...

Yunnan Province Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...

of southern

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

during the lower

Jurassic period The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. The Jurassic constitutes the second and m ...

. Identified from a nearly complete and exquisitely preserved

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

, it is the most complete basal sauropod currently known with intact

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

. Although its name was revealed in a 2010 Geological Society of America abstract by

Sankar Chatterjee Sankar Chatterjee (born May 28, 1943) is a paleontology, paleontologist, the Paul W. Horn Professor of Earth science, Geosciences at Texas Tech University and curator of Paleontology at the Museum of Texas Tech University. He earned his Doctor of ...

T. Wang T, or t, is the twentieth letter of the English alphabet. T may also refer to: Codes and units * T, Tera- as in one trillion * T, the symbol for "True" in logic * T, the usual symbol for period, the reciprocal of frequency * T, the symbol ...

, S.G. Pan, Z. Dong, X.C. Wu, and Paul Upchurch, it wasn't validly named and described until 2018. 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 ''Yizhousaurus sunae''.

Discovery and naming

The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

was discovered in 2002 and was excavated between October 20 through November 23. It consists of a near-complete skull and lower jaw, 31 vertebrae (nine cervical, fourteen dorsal, three sacral and five caudal), shoulder and pelvic girdles, most of both forelimbs and both thighs. The holotype was informally mentioned in a 2010 Geological Society of America abstract by

, S.G. Pan, Z. Dong, X.C. Wu, and Paul Upchurch. It was eventually named and described in 2018.

References

{{Taxonbar, from=Q2471020 Massopoda Dinosaur genera Sinemurian dinosaurs Lufeng Formation Dinosaurs of China Fossil taxa described in 2018 Taxa named by Hailu You Taxa named by Sankar Chatterjee