''Bashunosaurus'' is a genus of potentially macronarian sauropod dinosaur from the Middle

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), 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. ...

Shaximiao Formation The Shaximiao Formation () is a Middle to Late Jurassic aged geological formation in Sichuan, China, most notable for the wealth of dinosaurs fossils that have been excavated from its strata. The Shaximiao Formation is exposed in and around the ...

of Kaijiang,

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 ...

. The type and only species is ''Bashunosaurus kaijiangensis''.

Discovery

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 ...

of ''Bashunosaurus'', KM 20100, was discovered in sediments of the lower Shaximiao Formation in Maanping,

Sichuan Province Sichuan is a Provinces of China, province in Southwestern China, occupying the Sichuan Basin and Tibetan Plateau—between the Jinsha River to the west, the Daba Mountains to the north, and the Yunnan–Guizhou Plateau to the south. Its capita ...

, China. It consists of six

cervical vertebrae In tetrapods, cervical vertebrae (: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In saurop ...

, eight

dorsal vertebrae In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebra (anatomy), vertebrae of intermediate size between the ce ...

, a partial left

scapula The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side ...

, and a right

humerus The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

, ilium,

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

tibia The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...

, and

fibula The fibula (: fibulae or fibulas) or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. ...

. An additional right ilium, specimen KM 20103, was assigned as a

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype (biology), isotype ...

History

The name "Bashunosaurus kaijiangensis" first appeared in Ouyang's description of '' Abrosaurus'' in 1989, although without a description or diagnosis, making it a ''

nomen nudum In Taxonomy (biology), taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published ...

'' (i.e. a nickname that is unavailable for use as an actual scientific name). Li ''et al.'' (1999), however, attribute the naming to "Kuang, 1996", still considering it a ''nomen nudum''. Although it was finally formally named by Kuang in 2004, George Olshevsky's influential online ''Dinosaur Genera List'' continued to list it as a ''nomen nudum'' and possible synonym of '' Datousaurus''. It was largely ignored in modern literature until Dai ''et al.''s description of '' Yuzhoulong'' in 2022, where it is discussed.

Description

As a sauropod, ''Bashunosaurus'' would have been a large quadrupedal

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

with a robust body. Kuang (2004) estimated its length as about .

Classification

The precise classification of ''Bashunosaurus'' is unknown, with different authors proposing different ideas. Li ''et al.'' (1999) consider it a camarasaurid, while Kuang (2004) gives a more precise position in the Camarasaurinae, more derived than '' Abrosaurus'' but more basal than ''

Camarasaurus ''Camarasaurus'' ( ) is a genus of sauropod dinosaur that lived in North America during the Late Jurassic period. Its fossil remains have been found in the Morrison Formation, dating to the Kimmeridgian and Tithonian ages of the Jurassic, betwe ...

''. Molina-Perez and Larramendi (2020) list it as a primitive neosauropod similar to '' Bellusaurus'', '' Daanosaurus'', '' Dashanpusaurus'' and '' Klamelisaurus'', although they comment that it is also "similar to ''Abrosaurus'' and '' Datousaurus''". Dai ''et al.'' (2022) compare the taxon to '' Yuzhoulong'', noting the fact it was described as a macronarian, although they caution that a reappraisal is needed to confirm this in a cladistic context.

References

{{Taxonbar, from=Q5721716 Macronaria Dinosaur genera Callovian dinosaurs Shaximiao Formation Fossil taxa described in 2004 Dinosaurs of China