Beipiaosaurus ‭(‬Beipiao lizard‭)‬

Short Info

Beipiaosaurus ‭(‬Beipiao lizard‭)‬

Phonetic : bay-pyow-sore-us.

Named By : Xu,‭ ‬tang,‭ ‬Wang‭ ‬-‭ ‬1999

Diet : Herbivore / Omnivore

Size : Estimated 2.2 meters long

Type of Dinosaur : Small Theropod

Type Species : B.‭ ‬inexpectus‭ (‬type‭)‬

Found in : China,‭ ‬liaoning province‭ ‬-‭ ‬Yixian Formation

When it Lived : Early Cretaceous, 127-121 million years ago

Beipiaosaurus (also known as beIpjaU’so species of therizinosauroid dinosaurs which lived in Asia in the Early Cretaceous in the Yixian Formation. The first remains were discovered in the year 1996 and were officially recorded in 1999. Prior to finding Yutyrannus the dinosaurs were among the biggest dinosaurs known to have feathers. Beipiaosaurus is identified from three specimens that have various feather patterns which helped determine the feathering color , which was later discovered to be brown.


Beipiaosaurus holotype fossil
Maria E. McNamara, Fucheng Zhang, Stuart L. Kearns, Patrick J. Orr, André Toulouse, Tara Foley, David W. E. Hone, Chris S. Rogers, Michael J. Benton, Diane Johnson, Xing Xu & Zhonghe Zhou, CC BY 4.0, via Wikimedia Commons


They were rather small-sized therizinosaurs that measured 2.2 meters (7.2 feet) long and weighing between 45-91 kilograms (99-201 lbs) as opposed to larger and huge Segnosaurus and Therizinosaurus. Beipiaosaurus’ necks Beipiaosaurus were shorter than the majority of therizinosaurs and were characterized by necks with elongated lengths, which are adapted for high-browsing. Additionally, their foot shape differs from therizinosaurids and have a standard three-toed pes, instead of four like the other members.

The precise classification of therizinosaurs have previously been hotly debated because their prosauropod-like jaws and body structure suggest that they were mostly herbivores and not like theropods that are commonly found. Beipiaosaurus was believed to be an early therizinosauroid it has characteristics that suggests that every one of the therizinosauroids which include those that are more closely related to Therizinosauridae and the Therizinosauridae, are coelurosaurian theropods, not sauropodomorphs or ornithischian cousins as was once thought.


Beipiaosaurus skeletal Headden
Jaime A. Headden (User:Qilong), CC BY 3.0, via Wikimedia Commons


In the year 1996, the villager Li Yinxian stumbled upon the skeletons of a theropod dinosaur in Sihetun. Sihetun. In the next year, it was discovered that it had been taken from the lower bed in the Yixian Formation and could be an individual. The discovery was made on May 27th, 1999 the discovery was announced in the renowned journal Nature and the species that is considered to be the prototype Beipiaosaurus was named and described by Xu Xing, Tang Zhilu and Wang Xiaolin. The name Beipiaosaurus is generic. Beipiaosaurus can be translated to “Beipiao lizard” after Beipiao located in China close to the spot of the discovery. Beipiaosaurus is identified as one specie, B. inexpectus, the name of the specific species, meaning “unexpected” in Latin, which refers to “surprising features in these animals”.

The Holotype (type specimen) of Beipiaosaurus inexpectus IVPP V11559, was found in the Jianshangou Beds of Yixian Formation in Liaoning Province, China. The specimen was discovered in sediments deposited in the Aptian phase that was part of the Early Cretaceous period, approximately 130 millennia ago. It is part of the collections of the Institute of Vertebrate Paleontology and Paleoanthropology located located in Beijing, China. It is comprised of a fragmented sub-adult skeleton which is disarticulated in large part. Numerous fossilized bones were found from the cranial area, which included: cranial pieces teeth, a mandible three cervical vertebrae four dorsal vertebrae dorsal ribs two sacral vertebrae twenty-five caudal vertebrae that have three chevrons, a pygostyle as well as an incomplete scapula and furcula as well as both coracoids, both forelimbs and both ilia pubis incomplete and an ischium that was not fully formed and a femur, as well as both the tibiae (one incomplete) and a fibula that was not fully formed astragalus and calcaneum and calcaneum, as well as metatarsals, tarsals and pedal unguals, manual and pedal as well as skin impressions from the primitive plumage. The pelvic girdle and the caudal vertebrae were found during a excavation of the fossil quarry. They were the first parts of the holotype to be discovered. These newly discovered parts helped complete the holotype.

Another instance, STM 31-1, a partial skeleton was discovered by Xu and co. 2009, who have preserved an impressive covering of distinct feathers, which are elongated. The specimen comprised an entire skull and sclerotic circle and the mandible, as well as the axis bone and the atlas nine more cervical vertebrae and dorsal vertebrae. 17 cervical ribs, 12 dorsal dorsalribs both in scapulae, and coracoids, a complete humerus, proximal and the humerus with a full radius as well as distal radius one full distal and ulna as well as metacarpals and a few carpals. The skull’s rear of this specimen was severely crushed. Li et al. 2014 referred to a 3rd specimen, which was identified under the code BMNHC”PH000911. This specimen comes from the Sihetun locality in Beipiao County in Liaoning Province and is a compromise of a partial person that has preserved the skull (badly crushed) as well as the bulk of the vertebral column both arms, as well as other postcrania. The traces of feather integument were abundantly found in the neck region.

Beipiaosaurus were tiny-sized therizinosaurs that measured 2.2 millimeters (7.2 feet) in length. prior to finding Yutyrannus They were among the biggest dinosaurs discovered to have feathers. It is believed that they the weight of 45-91 grams (99 to 201 lbs). Therizinosaurids that are more advanced have four toes that function, however, Beipiaosaurus’ feet Beipiaosaurus have a smaller inner toes, which suggests that the condition of therizinosaurid could be derived from a three-toed Therizinosauroid ancestor. The head was huge compared to other therizinosaurs and the lower jaw extending to about the equal to the length of the femur. The neck appears to be smaller compared the other therizinosaurs. In 2003, the pygostyle comprised of the fused five last vertebrae of the tail was further described and suggested that the initial role of the pygostyle not connected to feathers of the pennaceous.

Source: Wikipedia