''Similicaudipteryx'', meaning "similar to ''

Caudipteryx ''Caudipteryx'' (meaning "tail feather") is a genus of small oviraptorosaur dinosaurs that lived in Asia during the Early Cretaceous, around 124.6 million years ago. They were feathered and extremely birdlike in their overall appearance, to the ...

''" (which itself means "tail feather"), 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 ...

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

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 ...

of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Caudipteridae Caudipteridae is an extinct family of oviraptorosaurian dinosaurs known from the Early Cretaceous of China. Found in the Yixian and Jiufotang Formations, the group existed between 125 and 120 million years ago. Distinguishing characteristics of ...

Discovery and naming

In 2007 the find of a new caudipterid was reported. In 2008 the new genus ''Similicaudipteryx'', with as

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 ...

''Similicaudipteryx yixianensis'', was named and described by He Tao,

Wang Xiaolin Wang may refer to: Names * Wang (surname) (王), a common Chinese surname * Wāng (汪), a less common Chinese surname * Titles in Chinese nobility * A title in Korean nobility * A title in Mongolian nobility Places * Wang River in Thailand ...

and Zhou Zonghe. The generic name, derived from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''similis'', "resembling", refers to its similarity to the closely related ''

''. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

refers to its provenance from Yixian County. Presently, ''S. yixianensis'' is the only species named in the genus. 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 ...

specimen, IVPP V 12556, was recovered from the

Jiufotang Formation The Jiufotang Formation () is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms (see Jehol Biota). It is a member of the Jehol group. T ...

of northeastern

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 ...

, dating to the early

Cretaceous Period The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 77.1 million years, it is the ninth and longest geologi ...

middle

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

stage, about 120 million years ago or perhaps early

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

stage, about 112 million years old. It consists of a nearly complete skeleton of an adult individual compressed on a plate, that however lacks the skull, the front neck and the hands. In 2010, two additional specimens with extensive feather preservation were referred to ''Similicaudipteryx'', one of a juvenile, STM4-1, and the other of a much larger juvenile, STM22-6. Both were reported as found in the

Yixian Formation The Yixian Formation (; formerly Romanization of Chinese, transcribed as Yihsien Formation or Yixiang Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the Barremian stage of the Early Cretaceous. I ...

, dating to the early

stage, about 124 million years ago. However, these have since been re-interpreted as belonging to the related species ''

Incisivosaurus gauthieri ''Incisivosaurus'' ("incisor lizard") is a genus of small, probably herbivorous theropod dinosaurs from the early Cretaceous Period of what is now the People's Republic of China. The first specimen to be described (by Xu ''et al.'' in 2002), IVPP ...

''. In 2010

Gregory S. Paul Gregory Scott Paul (born December 24, 1954) is an American freelance researcher, author and illustrator who works in paleontology. He is best known for his work and research on theropoda, theropod dinosaurs and his detailed illustrations, both l ...

renamed the species to ''Caudipteryx yixianensis'',Paul, G.S., 2010, ''The Princeton Field Guide to Dinosaurs'', Princeton University Press p. 149 but this has found no acceptance.

Description

''Similicaudipteryx'' was a small oviraptorosaur similar to, but larger than, the perhaps closely related ''Caudipteryx''. Paul in 2010 estimated the length at one metre, the weight at seven kilogrammes. Like ''Caudipteryx'', it had a short snout with a downcurved lower jaw. It had relatively short arms and long legs. ''Similicaudipteryx'' also differed from its relatives by possessing a dagger-shaped

pygostyle Pygostyle is a skeletal condition in which the final few caudal vertebrae are fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these. The pygostyle is the main component o ...

(the bone at the end of the tail to which feathers anchor in birds) consisting of the two most extreme tail vertebrae and several unique features of the back vertebrae. The

pubic bone In vertebrates, the pubis or pubic bone () forms the lower and anterior part of each side of the hip bone. The pubis is the most forward-facing (ventral and anterior) of the three bones that make up the hip bone. The left and right pubic bones ar ...

was exceptionally long relative to the ilium. The only other oviraptorosaur reported to have a pygostyle is ''

Nomingia ''Nomingia'' is a genus of Oviraptorosauria, oviraptorosaur theropod dinosaur hailing from the Late Cretaceous Bugin Tsav Beds of Mongolia. Discovery and naming The remains, consisting of most of the vertebral column, pelvic girdle and left ...

'', though the feature is widespread in more advanced birds and appears to have evolved at least twice. The holotype specimen lacks traces of feathers, but He and colleagues speculated that they were probably present based on its pygostyle, the anchor point of long tail feathers (rectrices) in modern birds.

Phylogeny

''Similicaudipteryx'' was by its describers assigned to the

. An exact

cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

analysis of its position was not performed.

References

{{Taxonbar, from=Q132745 Oviraptorosauria Dinosaur genera Aptian dinosaurs Jiufotang Formation Fossil taxa described in 2008 Dinosaurs of China

Discovery and naming

Description

Phylogeny

See also

References