Remains of the stegosaur, that included bones from the back, shoulder, thigh, feet, and ribs, as well as several armor plates, date to the Bajocian phase of the Middle Jurassic period– much earlier than many understood stegosaurs.
A team from the Chongqing Bureau of Geological and Mineral Resource Exploration and Development in China and Londons Natural History Museum called it Bashanosaurus primitivus– “Bashan” in reference to the ancient name for the location of Chongqing in China where the dinosaur was found, and the Latin for first– primitivus.
The brand-new dinosaur, which wandered the world 168 million years earlier, plays a part in discovering how the stegosaurs developed– of which, to this day, little is understood.
It has a smaller and less established should blade, narrower and thicker bases to its armor plates, and other functions that are various from all other Middle Jurassic stegosaurs found up until now. Nevertheless, it does have resemblances with some of the first armored dinosaurs, which are over 20 million years older.
” All these functions are clues to the stegosaurs put on the dinosaur household tree,” says Dr. Dai Hui from Chongqing Bureau of Geological and Mineral Resource Exploration and Development who led the research. “Bashanosaurus can be identified from other Middle Jurassic stegosaurs, and clearly represents a new species.
” Whats more, our analysis of the family tree shows that it is one of the earliest-diverging stegosaurs along with the Chongqing Lizard (Chungkingosaurus) and Huayangosaurus. These were all discovered from the Middle to Late Jurassic Shaximiao Formation in China, recommending that stegosaurs may have come from Asia,” adds Hui.
Quickly recognizable by the substantial back plates, long tail spikes, and tiny head, stegosaurs were four-legged, plant-eating dinosaurs that lived throughout the Jurassic and early Cretaceous durations. Stegosaur fossils have been discovered on all continents other than for Antarctica and Australia, and 14 types of stegosaur have been recognized so far.
Widely known members of Stegosauria include Huayangosaurus (among the most primitive stegosaurs), Gigantspinosaurus, significant for its enormous shoulder spinal columns, and Miragaia for its exceptionally long neck. However, the fragmentary fossil material has impeded efforts to understand how the stegosaurs evolved and how they associate with one another.
With the discovery of this new types the mystery has started to clear up. Bashanosaurus primitivus has several primitive features that resemble the earliest stegosaurs like Huayangosaurus and Gigantspinosaurus and early-branching thyreophorans (armored dinosaurs). These include longer tail vertebrae, a shoulder blade that is narrower and flares out, and functions of the back vertebrae that are similar to the early armored dinosaur Scelidosaurus, which lived during the Early Jurassic.
The fossilized remains of Bashanosaurus also reveal a host of features that make it unique from other recognized stegosaurs. For example, the bony point at the end of the shoulder blade is little and less well established than in other stegosaurs; a bony projection of the thighbone (4th trochanter) is positioned listed below the middle of the shaft; and the bases of the armor plates curve outwards and are thicker than the plates on the backs of its later family members.
” The discovery of this stegosaur from the Middle Jurassic of China adds to an increasing body of proof that the group developed in the early Middle Jurassic, or maybe even in the Early Jurassic, and as such represent a few of the earliest recognized bird-hipped dinosaurs,” states Dr. Susannah Maidment, co-author and paleontologist at Londons Natural History Museum.
” China appears to have actually been a hotspot for stegosaur variety, with many types now understood from the Middle Jurassic right the method through up until completion of the Early Cretaceous period.”
Reference: “New Stegosaurs from the Middle Jurassic Lower Member of the Shaximiao Formation of Chongqing, China” by Dai Hui, Li Ning, Susannah C. R. Maidment, Wei Guangbiao, Zhou Yuxuan, Hu Xufeng, Ma Qingyu, Wang Xunqian, Hu Haiqian and Peng Guangzhao, 3 March 2022, Journal of Vertebrate Paleontology.DOI: 10.1080/ 02724634.2021.1995737.
Bashanosaurus primitivus– the newest and oldest species of stegosaur in Asia. Credit: Banana Art Studio
Bashanosaurus primitivus roamed the earth around 168 million years ago during the Middle Jurassic duration, suggesting that stegosaurs might have come from Asia.
Relatively little, however fearsome-looking stegosaur measured about 2.8 meters (9 feet) from nose to tail– however scientists cant tell whether the remains are those of an adult or juvenile.
A brand-new types of one of the most identifiable kinds of dinosaur is the oldest stegosaur ever found in Asia, and among the earliest unearthed throughout the world, according to research study released today in the peer-reviewed Journal of Vertebrate Paleontology.
