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

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of basal sauropodiform

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

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 ar ...

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 ...

of southern

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 ...

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 Mya. The Jurassic constitutes the middle period of ...

. Identified from a nearly complete and exquisitely preserved

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

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

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

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

Sankar Chatterjee Sankar Chatterjee (born May 28, 1943) is a paleontologist, and is the Paul W. Horn Professor of Geosciences at Texas Tech University and Curator of Paleontology at the Museum of Texas Tech University. He earned his Ph. D. from the University of ...

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

type species In 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 species that contains the biological type specimen ...

is ''Yizhousaurus sunae''.

Discovery and naming

The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

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

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

References

Early Jurassic dinosaurs of Asia Sauropodomorphs Paleontology in Yunnan Fossil taxa described in 2018 {{Sauropodomorph-stub