Hexinlusaurus

Hexinlusaurus is a genus of basal ornithischian dinosaur from the Middle Jurassic of China. The holotype (ZDM T6001, Zigong Dinosaur Museum, Dashanpu, People's Republic of China), consists of an almost complete, articulated skull and some postcranial material, collected from a terrestrial sandstone within the Lower Shaximiao Formation (?Bajocian) at the famous dinosaur-bearing quarries at Dashanpu. A paratype (ZDM T6002) consists of a partial skull and postcranial remains. Previously, it had been described as a species of Yandusaurus, Y. multidens (He and Cai, 1983), but was reclassified as a new taxon by Paul M. Barrett, Richard J. Butler and Fabien Knoll in 2005, who diagnosed this anatomically conservative species as follows: "A small ornithischian dinosaur distinguished from all other basal ornithischians by a single autapomorphy, the presence of a marked concavity that extends over the lateral surface of the postorbital." The etymology of the genus name honors Professor He Xin-Lu (from the Chengdu University of Technology) who originally named the specimen as Y. multidens + the Greek sauros (=lizard). Hexinlusaurus was a small, fleet-footed herbivore.

Other dinosaurs known from Dashanpu include the sauropod Shunosaurus, the theropod Gasosaurus, and the stegosaur Huayangosaurus.

Before being officially named Hexinlusaurus, this genus was briefly known under the informal name "Proyandusaurus". This name originally appeared in an abstract attributed to Fabien Knoll, which was apparently published without his consent.[1][2]

Hexinlusaurus
Temporal range: Middle Jurassic, Bajocian
Hexinlusaurus multidens
Skeletal restoration
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Clade: Genasauria
Clade: Neornithischia
Genus: Hexinlusaurus
Barrett et al., 2005
Species:
H. multidens
Binomial name
Hexinlusaurus multidens
(He & Cai, 1983 [originally Yandusaurus multidens])

Sources

  • Barrett, P.M.; Butler, R. J.; Knoll, F. (2005). "Small-bodied ornithischian dinosaurs from the Middle Jurassic of Sichuan, China". Journal of Vertebrate Paleontology. 25: 823–834. doi:10.1671/0272-4634(2005)025[0823:sodftm]2.0.co;2.
  • Butler, Richard J.; Upchurch, Paul; Norman, David B. (2008). "The phylogeny of the ornithischian dinosaurs". Journal of Systematic Palaeontology. 6 (1): 1–40. doi:10.1017/S1477201907002271.
  • Knoll, F. 1999. The family Fabrosauridae. In: J. I. Canudo and G. Cuenca-Bescós (Eds.): IV European Workshop on Vertebrate Palaeontology, Albarracin (Teruel, Spain), junio de 1999. Programme and Abstracts, Field guide. Servicio Publicaciones Universidad de Zaragoza, 54.
  • He, X.-L.; Cai, K.-J. (1983). "A new species of Yandusaurus (hypsilophodont dinosaur) from the Middle Jurassic of Dashanpu, Zigong, Sichuan". Journal of Chengdu College of Geology (Supplement 1): 5–14.
Agilisaurus

Agilisaurus (; 'agile lizard') is a genus of ornithischian dinosaur from the Middle Jurassic Period of what is now eastern Asia. The name is derived from the Latin "agilis" meaning 'agile' and the Greek "sauros" meaning 'lizard', and refers to the agility suggested by its lightweight skeleton and long legs. Its tibia (lower leg bone) 207.0 mm in length, was longer than its femur (upper leg bone) 199.0 mm in length, which indicates that it was an extremely fast bipedal runner, using its long tail for balance, although it may have walked on all fours when browsing for food. It was a small herbivore, about 2 meters (6.5 feet) in length, and like all ornithischians, it had a beak-like structure on the ends of both upper and lower jaws to help it crop plant material.

Anchisauria

The Anchisauria were a clade of sauropodomorph dinosaurs that lived during the Late Triassic and Early Jurassic. The name Anchisauria was first used by Galton and Upchurch in the second edition of The Dinosauria. Galton and Upchurch assigned two families of dinosaurs to the Anchisauria: the Anchisauridae and the Melanorosauridae. The more common prosauropods Plateosaurus and Massospondylus were placed in the sister clade Plateosauria.

However, recent research indicates that Anchisaurus is closer to sauropods than traditional prosauropods; thus, Anchisauria would also include Sauropoda.The following cladogram simplified after an analysis presented by Blair McPhee and colleagues in 2014.

Averostra

Averostra, or "bird snouts", is a clade that includes most theropod dinosaurs that have a promaxillary fenestra (fenestra promaxillaris), an extra opening in the front outer side of the maxilla, the bone that makes up the upper jaw. Two groups of averostrans, the Ceratosauria and the Orionides, survived into the Cretaceous period. When the Cretaceous–Paleogene extinction event occurred, ceratosaurians and two groups of orionideans within the clade Coelurosauria, the Tyrannosauroidea and Maniraptoriformes, were still extant. Only one subgroup of maniraptoriformes, Aves, survived the extinction event and persisted to the present day.

Avetheropoda

Avetheropoda, or "bird theropods", is a clade that includes carnosaurians and coelurosaurs to the exclusion of other dinosaurs.

Bathonian

In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian age succeeds the Bajocian age and precedes the Callovian age.

Cerapoda

Cerapoda ("ceratopsians and ornithopods") is a clade of the dinosaur order Ornithischia.

Changchunsaurus

Changchunsaurus (meaning "Changchun lizard") is an extinct genus of small herbivorous parksosaurid dinosaur from Early Cretaceous deposits of Gongzhuling, Jilin, China. It is the first named dinosaur genus from Jilin.

Dinosauriformes

Dinosauriformes is a clade of archosaurian reptiles that include the dinosaurs and their most immediate relatives. All dinosauriformes are distinguished by several features, such as shortened forelimbs and a partially to fully perforated acetabulum, the hole in the hip socket traditionally used to define dinosaurs. The oldest known member is Asilisaurus, dating to about 245 million years ago in the Anisian age of the middle Triassic period.

Jeholosaurus

Jeholosaurus is a genus of ornithischian dinosaur from the Early Cretaceous Period. It is thought to have been a herbivorous small ornithopod.

Jingshanosaurus

Jingshanosaurus (meaning "Jingshan lizard") is a genus of sauropodomorph dinosaurs from the early Jurassic period.

Kulindadromeus

Kulindadromeus was a herbivorous dinosaur, a basal neornithischian from the Jurassic. The first Kulindadromeus fossil was found in Russia. Its feather-like integument is evidence for protofeathers being basal to Dinosauria as a whole, rather than just to Coelurosauria, as previously suspected.

Neornithischia

Neornithischia ("new ornithischians") is a clade of the dinosaur order Ornithischia. They are the sister group of the Thyreophora within the clade Genasauria. Neornithischians are united by having a thicker layer of asymmetrical enamel on the inside of their lower teeth. The teeth wore unevenly with chewing and developed sharp ridges that allowed neornithischians to break down tougher plant food than other dinosaurs. Neornithischians include a variety of basal forms historically known as "hypsilophodonts", including the Parksosauridae; in addition, there are derived forms classified in the groups Marginocephalia and Ornithopoda. The former includes clades Pachycephalosauria and Ceratopsia, while the latter typically includes Hypsilophodon and the more derived Iguanodontia.

Neotheropoda

Neotheropoda (meaning "new theropods") is a clade that includes coelophysoids and more advanced theropod dinosaurs, and the only group of theropods who survived the Triassic–Jurassic extinction event. Yet all of the neotheropods became extinct during the early Jurassic period except for Averostra.

Orionides

Orionides is a clade of tetanuran theropod dinosaurs from the Middle Jurassic to the Present. The clade includes most theropod dinosaurs, including birds.

Ornithischia

Ornithischia () is an extinct clade of mainly herbivorous dinosaurs characterized by a pelvic structure similar to that of birds. The name Ornithischia, or "bird-hipped", reflects this similarity and is derived from the Greek stem ornith- (ὀρνιθ-), meaning "of a bird", and ischion (ἴσχιον), plural ischia, meaning "hip joint". However, birds are only distantly related to this group as birds are theropod dinosaurs.Ornithischians with well known anatomical adaptations include the ceratopsians or "horn-faced" dinosaurs (e.g. Triceratops), armored dinosaurs (Thyreophora) such as stegosaurs and ankylosaurs, pachycephalosaurids and the ornithopods. There is strong evidence that certain groups of ornithischians lived in herds, often segregated by age group, with juveniles forming their own flocks separate from adults. Some were at least partially covered in filamentous (hair- or feather- like) pelts, and there is much debate over whether these filaments found in specimens of Tianyulong, Psittacosaurus, and Kulindadromeus may have been primitive feathers.

Orodrominae

Orodrominae is a subfamily of parksosaurid dinosaurs from the Cretaceous of North America and Asia.

Xiaosaurus

Xiaosaurus ("dawn lizard", ), is a genus of small herbivorous dinosaur from the middle Jurassic, approximately 169 to 163 mya. Xiaosaurus lived in what is now the Sichuan Basin of China.

In 1979 and 1980, two specimens were discovered of a small herbivorous dinosaur during excavations near Dashanpu in Sichuan. In 1983 Dong Zhiming and Tang Zilu named the fossils under the type species Xiaosaurus dashanpensis. The generic name is derived from Chinese xiáo, 曉, "dawn", a reference to the age of the fossil. The specific name refers to Danshanpu.The holotype, IVPP V6730A, was found in the lower Xiashaximiao Formation of which the age is uncertain: both the Bajocian and the Bathonian–Callovian have been proposed. It consists of a partial skeleton including a jaw fragment with a single tooth, two cervical vertebrae, four caudal vertebrae, a humerus, a partial left femur and a complete right hindlimb. The paratype IVPP V6730B is a second partial skeleton including a right femur, a dorsal vertebra, two sacral vertebrae, a phalanx, a rib and two teeth.

In 1992 Peng Guangzhao renamed Agilisaurus multidens He & Cai 1983 (now Hexinlusaurus) into a second species of Xiaosaurus: Xiaosaurus multidens, but this has not been accepted.

Xiaosaurus was a small bipedal animal with an estimated length of one metre. The femur is 11 centimetres (4.3 in) long.

The remains are too fragmentary to easily classify the genus. The describers assigned it both to the Fabrosauridae and the Hypsilophodontidae, considering it an evolutionary link between Lesothosaurus and Hypsilophodon. Xiaosaurus has sometimes been considered a nomen dubium and an ornithischian of uncertain affinities, possibly a basal cerapod or marginocephalian. However, Paul Barrett et al. in 2005 concluded it to be provisionally valid, as it possessed a single unique derived trait or autapomorphy: a mediolaterally (seen from the front) straight humerus.

Xixiposaurus

Xixiposaurus is a genus of prosauropod dinosaur which existed in what is now Lower Lufeng Formation, China during the lower Jurassic period. It was first named by Sekiya Toru in 2010 and the type species is Xixiposaurus suni.

Yandusaurus

Yandusaurus is a genus of herbivorous basal neornithischian dinosaur from the Bathonian age (middle Jurassic, approximately 168 to 162;Ma) of China.

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