Gongxianosaurus

Gongxianosaurus is a genus of basal sauropod dinosaur from the early Jurassic Period (Toarcian stage). The only species is Gongxianosaurus shibeiensis. Based on four fragmentary to complete specimens found in China (Sichuan Province), it is one of the most completely known early sauropods. The skeleton is known in large part, missing both the hand and the majority of the skull.Gongxianosaurus was firstly named and described in a short note published in 1998; however, a comprehensive description has yet to be published.Gongxianosaurus shibeiensis was named for the place it was found, near the village Shibei in Gong County (珙县; Pinyin: Gǒng Xiàn).

Gongxianosaurus may have reached 14 metres (46 ft) in length. Like other sauropods, it moved quadrupedally (on four legs), as indicated by the elongated fore limbs that reached 70 to 75% of hind limb length. The pedal phanlanges were short and robust, as typical for sauropods. The pedal phalangeal formula, counting the number of phalanges for each digit starting from the innermost, was 2-3-4-5-1. All but the outermost digit ended in claws. Unlike in other sauropods, pleurocoels (deep lateral excavations of the vertebrae) were absent; thus, the vertebrae would have been quite massive. The sacrum was made of three fused sacral vertebrae, fewer than in later sauropods. The chevrons were unbifurcated.

An important characteristic of sauropod limbs is their reduced ossification – the tendency to replace bone by cartilage. Gongxianosaurus is the only known sauropod with ossified distal tarsals. Thus, either Gongxianosaurus was one of the basalmost sauropods, or ossified distal tarsals were present in other early sauropods but are simply not preserved due to the fragmentation of the specimens.