Archaeocursor asiaticus – A New Ornithischian from China

Researchers have described a brand new dinosaur from fossils present in southwestern China.   The dinosaur has been named Archaeocursor asiaticus.  It’s the oldest ornithischian (bird-hipped) dinosaur from Asia described thus far.  Phylogenetic evaluation suggests Archaeocursor additionally represents the earliest-diverging ornithischian recognized from Asia. This discovery extends the recognized presence of ornithischian dinosaurs in East Asia to the Pliensbachian and even late Sinemurian levels of the Early Jurassic.

Image credit score: Yao et al

Archaeocursor asiaticus

The Early Jurassic ornithischian dinosaurs in Laurasia are dominated by armoured dinosaurs.  Different forms of ornithischian are uncommon. Scientists from Yunnan College, the Chinese language Academy of Sciences, the Southeast Sichuan Geological Staff and the Chongqing Institute of Palaeontology examined an almost full left femur.  The fossil, specimen quantity L01-HY999, was discovered roughly two kilometres north of Chongqing Central Park in Yubei District, Chongqing Municipality.  The leg bone fossil comes from the Decrease Jurassic Dongyuemiao Member of the Ziliujing Formation.

Osteohistological evaluation of the bone signifies that it got here from a younger grownup.  The animal would have been lower than a metre in size.  The genus identify is derived from the Latin phrases “archaeo”, “cursor” and “asiaticus” which translate as “outdated runner from Asia”.  The crew performed an in-depth phylogenetic evaluation that positioned A. asiaticus because the earliest-diverging ornithischian dinosaur but found in Asia, albeit with weak assist. Archaeocursor asiaticus is recognized as an ornithischian dinosaur primarily based on distinctive morphological options, specifically a broad, wing-like anterior trochanter and a well-developed flange-like fourth trochanter, which differentiate it inside Ornithischia.

Associated to Eocursor parvus from South Africa

Ornithischian fossils are scarce in Early Jurassic deposits of Asia, primarily reported from the contemporaneous Decrease Jurassic Lufeng and Fengjiahe formations in Yunnan province, additionally in
southwestern China.  The phylogenetic evaluation indicated that Archaeocursor asiaticus was intently associated to Eocursor parvus. Eocursor is a genus of basal ornithischian dinosaur that lived in South Africa within the Early Jurassic. Its fossils had been considered a lot older relationship from the Late Triassic (Norian). Nevertheless, it isn’t doable right now to find out the age of this fossil materials with confidence. Many palaeontologists take into account Eocursor to have lived throughout the Sinemurian (Early Jurassic).

To learn an article from 2007 in regards to the discovery of E. parvus: The Ancestor of Stegosaurus, Triceratops and so forth.

Ornithischian dinosaurs originated from Gondwana and migrated to the North Hemisphere within the Early Jurassic. Nevertheless, the timing of their arrival in East Asia is obscure. The shut relationship between Archaeocursor asiaticus and Eocursor parvus, regardless of their distance (China and South Africa respectively), suggests a possible ornithischian origin in Gondwana. In some unspecified time in the future there adopted a northward migration to Laurasia and ultimately to East Asia throughout the Pliensbachian. This timing may precede the arrival of armoured dinosaurs within the area.

Every little thing Dinosaur acknowledges the help of the corresponding writer of the scientific paper Xi Yao within the compilation of this text.

The scientific paper: “New proof for the earliest ornithischian dinosaurs from Asia” by Xi Yao, Qi Zhao, Tingcong Ren, Guangbiao Wei and Xing Xu printed in iScience.

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