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.[1]

Changchunsaurus
Temporal range: Early-Late Cretaceous, Aptian–Cenomanian
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Family: Parksosauridae
Genus: Changchunsaurus
Zan et al., 2005
Species:
C. parvus
Binomial name
Changchunsaurus parvus
Zan et al., 2005

Description

Changchunsaurus was first named by Zan Shu-Qin, Chen Jun, Jin Li-Yong and Li Tao in 2005. The type and only known species is C. parvus ("parvus" meaning "petite"), named for its small size. It is known from a skull and skeleton and additional skull fragments. All specimens of Changchunsaurus were collected from the Quantou Formation of the Songliao Basin, dating to the AptianCenomanian stages. Changchunsaurus is based on the holotype JLUM L0403-j–Zn2, a skeleton and skull, with a premaxilla (upper beak) and partial lower jaw also known. Only the skull was figured and described in the official description.[1]

According to Zan et al. 2005, who described it, the animal shows a combination of features like those of derived ornithopods (reduction in size or loss of some skull fenestrae or holes), and features like those of more basal ornithopods (for example, five teeth in each premaxilla, short toothless portion of upper beak, and a small gap between beak teeth and cheek teeth). There is a projection that sticks out from the side of the jugal or cheekbone, with what is described as a "nubble structure". The type individual was a small animal, around 1 meter long (3.3 feet, with a skull 11.5 centimeters long (4.5 inches). It was originally classified as a basal ornithopod, family unknown, although it was not included in a formal phylogenetic analysis.[1]

Later, some referred specimens were described and in 2010 its cranial anatomy was revised.[2]

Classification

In Butler et al., 2011, the postcranial osteology was described for the first time and a large phylogenetic analysis confirmed its position as a basal ornithopod which was found to be closely related to another Chinese ornithopod, Jeholosaurus[3] and later to the newly described Chinese ornithopod Haya.[4] Han et al. named this clade "Jeholosauridae" in 2012.[5]

The following cladogram was based on analysis by Makovicky et al., 2011.[4]

Neornithischia

Stormbergia

Agilisaurus

Hexinlusaurus

Cerapoda

Marginocephalia

Ornithopoda

Orodromeus

Jeholosauridae

Haya

Changchunsaurus

Jeholosaurus

Hypsilophodon

to Iguanodontia

References

  1. ^ a b c Zan Shu-Qin; Chen Jun; Jin Li-Yong; Li Tao (2005). "A primitive ornithopod from the Early Cretaceous Quantou Formation of Central Jilin, China". Vertebrata PalAsiatica (in Chinese and English). 43 (3): 182–193.
  2. ^ Jin Liyong; Chen Jun; Zan Shu-Qin; Richard J. Butler & Pascal Godefroit (2010). "Cranial anatomy of the small ornithischian dinosaur Changchunsaurus parvus from the Quantou Formation (Cretaceous: Aptian–Cenomanian) of Jilin Province, northeastern China". Journal of Vertebrate Paleontology. 30 (1): 196–214. doi:10.1080/02724630903412372.
  3. ^ Richard J. Butler; Jin Liyong; Chen Jun; Pascal Godefroit (2011). "The postcranial osteology and phylogenetic position of the small ornithischian dinosaur Changchunsaurus parvus from the Quantou Formation (Cretaceous: Aptian–Cenomanian) of Jilin Province, north-eastern China". Palaeontology. 54 (3): 667–683. doi:10.1111/j.1475-4983.2011.01046.x.
  4. ^ a b Makovicky, Peter J.; Brandon M. Kilbourne; Rudyard W. Sadleir; Mark A. Norell (2011). "A new basal ornithopod (Dinosauria, Ornithischia) from the Late Cretaceous of Mongolia". Journal of Vertebrate Paleontology. 31 (3): 626–640. doi:10.1080/02724634.2011.557114.
  5. ^ Han, Feng-Lu; Paul M. Barrett; Richard J. Butler; Xing Xu (2012). "Postcranial anatomy of Jeholosaurus shangyuanensis (Dinosauria, Ornithischia) from the Lower Cretaceous Yixian Formation of China". Journal of Vertebrate Paleontology. 32 (6): 1370–1395. doi:10.1080/02724634.2012.694385.

External links

  • Changchunsaurus at Dinosaur.net.cn, with the article summary and photograph. (slow-loading)
Albertadromeus

Albertadromeus is an extinct genus of orodromine parksosaurid dinosaur known from the upper part of the Late Cretaceous Oldman Formation (middle Campanian stage) of Alberta, Canada. It contains a single species, Albertadromeus syntarsus.

Aptian

The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous epoch or series and encompasses the time from 125.0 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the Barremian and precedes the Albian, all part of the Lower/Early Cretaceous.The Aptian partly overlaps the upper part of the regionally used (in Western Europe) stage Urgonian.

The Selli Event, also known as OAE1a, was one of two oceanic Anoxic events in the Cretaceous period, which occurred around 120 Ma and lasted approximately 1 to 1.3 million years. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma.

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.

Cerapoda

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

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.

Echinodon

Echinodon (pronounced eh-KY-no-don) meaning "hedgehog tooth" in reference to the spines on its teeth (Ancient Greek: εχινος, romanized: echinos, lit. 'hedgehog', + ὀδών, odṓn, 'tooth'), occasionally known as Saurechinodon, is a genus of small European dinosaur of the early Cretaceous Period (Berriasian age), 140 million years ago.

Fruitadens

Fruitadens is a genus of heterodontosaurid dinosaur. The name means "Fruita tooth", in reference to Fruita, Colorado (USA), where its fossils were first found. It is known from partial skulls and skeletons from at least four individuals of differing biological ages, found in Tithonian (Late Jurassic) rocks of the Morrison Formation in Colorado. Fruitadens is the smallest known ornithischian dinosaur, with young adults estimated at 65 to 75 cm (26 to 30 in) in length and 0.5 to 0.75 kg (1.1 to 1.7 lb) in weight. It is interpreted as an omnivore and represents one of the latest-surviving heterodontosaurids.

Haya griva

Haya is an extinct genus of basal neornithischian dinosaur known from Mongolia.

Helioceratops

Helioceratops is a genus of neoceratopsian dinosaur from the Middle Cretaceous of China. The type species is H. brachygnathus, described in 2009 by a group of paleontologists led by Jin Liyong. Helioceratops was discovered in the Quantou Formation of China's eastern Jilin province and is known mostly from skull fragments. It reached a length of around 1.3 m (4.3 ft) and may have shared its habitat with Changchunsaurus.

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.

Lycorhinus

Lycorhinus is a genus of heterodontosaurid ornithischian dinosaur hailing from the Early Jurassic (Hettangian to Sinemurian ages) strata of the Elliot Formation located in the Cape Province, South Africa.

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.

Orionides

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

Orodrominae

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

Parksosauridae

Parksosauridae is a clade or family of small ornithischians which have previously been generally allied to hypsilophodontids. Parksosauridae is often considered a synonym of Thescelosauridae, but the two groups cannot be synonyms because Parksosauridae is defined as a stem, while Thescelosauridae is defined as a node.

Thescelosaurinae

Thescelosaurinae is a subfamily of ornithischian dinosaurs from the Early Cretaceous of Asia and the Late Cretaceous of North America.

Tianyulong

Tianyulong (Chinese: 天宇龍; Pinyin: tiānyǔlóng; named for the Shandong Tianyu Museum of Nature where the holotype fossil is housed) was a genus of heterodontosaurid ornithischian dinosaur. The only species was T. confuciusi, whose remains were discovered in Jianchang County, Western Liaoning Province, China.

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