Brief introduction of Triassic southern cross dragon

Southern Cross Dragon (scientific name: Staurikosaurus) is a genus of dinosaur suborder and extinct dinosaur. Southern Cross Dragon is a small theropod dinosaur. Southern Cross Dragon lived in Brazil in the late Triassic.

The only specimen of Southern Cross Dragon was found in the Virgin Mary stratum of Rio Grande in southern Brazil.

Because it was discovered in 1970, there were few examples of dinosaurs found in the southern hemisphere at that time, so the name of dinosaurs was named after the Southern Cross, a constellation that can only be seen in the southern hemisphere. The Southern Cross Dragon was first described by Edwin colbert, who worked in the American Museum of Natural History at that time.

The Southern Cross Dragon lived in the late Triassic Carney period (about 234.3 million-227.4 million years ago). It is one of the oldest known dinosaurs, with a body length of 2. 1 m, a tail length of about 80 cm and a weight of about 30 kg. Although its teeth and posture indicate that it is a carnivorous dinosaur, some researchers believe that it belongs to sauropods because the bones of Southern Cross are similar to those of primitive sauropods. The Southern Cross Dragon may represent a transitional period from the ancestor of sauropods to the branch evolution of theropods and sauropods. However, another unnamed fossil found in Arizona's colorful desert is considered to be a typical protosauropod dinosaur. It seems that the primitive sauropods evolved before the appearance of the Southern Cross Dragon. New research shows that Southern Cross Dragon, its close relatives, Tenontosaurus and Parasaurus, all belong to theropod, which evolved after sauropod and theropod evolved separately.

The fossil record of Southern Cross Dragon is extremely incomplete, with only most vertebrae, hind legs and jaws. However, because the fossil age is in the early dinosaur era and relatively primitive, most of the characteristics of the Southern Cross Dragon have been reconstructed. For example, the Southern Cross Dragon is often referred to as five fingers and five toes, which is a very primitive dinosaur feature. Ever since the discovery of the leg bones of the Southern Cross, the Southern Cross has been regarded as a fast-running animal. Southern Cross Dragon has only two vertebrae connecting pelvis and spinous column, which is an obvious primitive arrangement. The tail of the southern cross dragon may be long and thin; Compared with the weight, the tail of the late sauropod dinosaur was bigger and shorter.

The reconstructed mandible shows a sliding mandibular joint, which can make the mandible swing up and down. Therefore, the Southern Cross Dragon was able to push the smaller prey to the back of the throat along the small, backward-curved teeth. This feature was quite common among theropods at that time, but it disappeared in the later theropods, probably because they didn't need this way when swallowing smaller prey.

Because there is only one specimen of the Southern Cross at present, only Staurikosaurus pricei is known. Platts' Southern Cross was named after colbert's paleontology colleague Llewelyn Iver Price. But there are also other Australopithecidae dinosaurs, such as Murray and the Australopithecus Bryansmalli named by Long in 1985. Qin Dilong was found in strata with similar ages in Arizona and New Mexico. This shows that brachiopods are widely distributed in the Middle Pan-continent.

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