Omeisaurus is the Greek derivative of Omei Mountain Lizard. It is to be pronounced as ‘oh-me-sore-us’. Fossil records suggest that Omeisaurus had previously inhabited in eastern Asia sometime around the Late Jurassic Period which would be around one hundred and sixty million years ago. Details of anatomical studies suggest that these were generally large creatures with exceptionally long necks and were believed to be herbivorous in nature.
Omeisaurus has been believed to be the most common Sauropod that had inhabited Late Jurassic China. This is believed specifically because of the large number of fossil remains that have been discovered in this region. This unusually long animal had a large number of species that has been discovered in the past few decades. It is interesting to note that the smallest fossil discovered was around thirty feet in length from head to toe while there also have been fossils whose length alone have been measuring more than thirty feet. These animals were generally believed to have been moving in herds.
- It is worth mentioning in this context that the closest possible relative of Omeisaurus have been Mamenchisaurus who had even longer necks than Omeisaurus. They had as many as nineteen vertebrae in their necks when compared to Omeisaurus who had seventeen.
Omeisaurus was discovered and named by Yang Zhongjian , also known as C.C. Young (born in the Huaxian region of Shaanxi province. He was regarded as China’s foremost vertebrate paleontologist. Young had held professional posts at Geological Survey of China, Peking University and the Northwest University of Xi’an province. Young played an important role in the setting up of China’s Institute of Paleontology and Paleoanthropology in Beijing. Currently this institution houses the most important fossil collections and has international recognition in the world. Dr C.C. Young was responsible for excavations of the Peking Man site at Zhoukoudian. Dr Young also has held influential positions at the Beijing National History Museum. He was a principal supervisor in the various collection projects of fossilized remains and their further research during the 1970’s era.
- The cremated remains of Dr C.C. Young are still preserved at the Zhoukoudian museum site alongside his bosom colleagues Pei Wenzhong and Jia Lanpo.
- Dr Young has presided over quite a few of China’s important paleontological discoveries which include prosauropods like Lufengosaurus, Yunnanosaurus , an ornithopod named Tsintaosaururs ,the gigantic and famous Mamenchisaurus and the first stegosaur of China- Chialingosaurus.
The long neck of Omeisaurus probably had been associated to help it grasp foliage. Similar to other sauropods they also had a very large appetite. They had the ability to probably consume anything around one ton of plants in a single day. They also had a similar sauropodian body generally in a rounded nature that gave a small surface area when compared to volume. This typically helped to keep warm and reduced heat loss.
Partial fossils that included a head had been found in Mount Emei of China. The fossils were however in good conditions. But again there had been problems in identifying them. There previously had been speculations that the fossils were probably made from existing dinosaurs. Far back in 1996 there had been a study conducted by two scientists who claimed that Omeisaurus had been belonging to the family of Mamenchisaurus and more specifically Zigongosaurus.
However there had been previous rumors that the tail of Omeisaurus had a club at the end. However there had been no evidences of this in any of the fossils found till date. This led to the confusion of identifying Omeisaurus in its earlier stages. Later however this idea was summarily rejected and it was concluded that a club would result in a heavy end for this dinosaur and make it off balance.
- A very unique feature observed in Omeisaurus was its nostrils. These nostrils faced forwards as compared to other dinosaurs belonging to the same clan as exemplified in Brachiosaurus.
- Some of the other distinguishing anatomical features were- tall and large dorsal vertebrae, opisthocelous anterior dorsal vertebrae, well developed pleurocoels of the dorsal vertebrae, the neural spines were generally club like and the slightly amphicoelous anterior dorsal vertebrae.
The incredible long neck of Omeisaurus has been a cause of interest to all sections of Paleontologists. There have been different schools of thought that have considered Omeisaurus to be a relative while there have been others who have considered them to be a contemporary to the more famous Mamenchisaurus. Further detailed studies on the Upper Shaximiao Formation fossils concluded that Omeisaurus was later considered to be an intermediate. The existence of Omeisaurus in the lower Shaximiao deposits would have confirmed the replacement of Omeisaurus by Mamenchisaurus as Mamenchisaurus have been known only from the Upper Shaximiao.
- Omeisaurus fossils have been found out in large numbers and this indicates that they had a huge population. This also suggested that they were quite successfully adapted to the environment and resulted in huge populations.
- Other sauropods that belonged to the Omeisaurian clan were Dashanpusaurus , Abrosaurus, Shunosaurus (having a characteristic clubbed tail). Other dinosaurs which were co-inhabiting the Omeisaurus were Huayangosaurus (a stegosaur), Agilisaurus (a bipedal ornithischian). There were carnivores including Kaijiangosaurus, Chuandongocoelurus, Gasosaurus, Xuanhanosaurus, Leshansaurus, and Yangchuanosaurus. Yangchuanosaurus in particular could have been a special one in reference to Omeisaurus as they could have been a serious threat to the big giants when it came to their size.
Omeisaurus have been first described in 1939 and was described after Mount Omeishan which was a sacred mountain. It was here that the first fossil were found. Most of the skeletal fossils were found in the time of 1970-1980. This decade was more famously known as the Chinese Dinosaur Rush period.
Six species of Omeisaurus have been discovered till date. They are O. luoquanensis , O. Tianfuensis , O. Fuxiensis, O. changshouensis, , O. Junghsiensis and O. maoianus . Except the last one it should be interestingly mentioned that all the dinosaurs were named after the places they were first discovered.
- Mounted and preserved skeletal fossils of Omeisaurus are displayed at Ziging Dinosaur Museum in Ziging at Sichuan province. Beipei museum located at Chongquing also hosts a range of such fossils.