Yingshanosaurus

Yingshanosaurus (meaning "Yingshan lizard") is an extinct genus of stegosaurian dinosaurs from the Middle Jurassic of what is now Southwestern China. It is known from a partial skeleton discovered in 1983, including back, sacrum, and tail vertebrae, forelimb and hindlimb bones, shoulder and hip bones, and several osteoderms, including plates and a shoulder spine. The genus contains a single species, Yingshanosaurus jichuanensis, named and described in 1994. For some time after its discovery and scientific description, many paleontologists were unaware of the Chinese research published on it and questioned its validity.

Like other stegosaurs, Yingshanosaurus was a slow-moving, quadrupedal herbivore. At 4–5 metres (13–16 ft) long, it is a medium-sized member of this group. It's forelimbs are relatively short in relation to its hindlimbs, and it has a wide torso with a broad back. Several flattened, semi-triangular plates were arranged in pairs along the neck, back, and tail. The large spine near its shoulder likely functioned as a form of protection from predators for its torso. It probably had a pair of spines at the tip of its tail like other stegosaurs, though none are currently known. Unlike many earlier species, the fenestrae (holes) between vertebrae in the sacrum are almost completely closed. While all of the stegosaurs contemporary with Yingshanosaurus are part of earlier-diverging groups in this clade, its anatomy suggests it had derived traits consistent with members of the more exclusive subfamily Stegosaurinae.

Yingshanosaurus is known from the Upper Shaximiao Formation, which dates to the Bathonian age of the Jurassic period. This formation has also yielded abundant fossils of diverse dinosaurs, including other stegosaurs and many sauropods, theropods, and early ornithischians, in addition to turtles, crocodyliforms, mammal relatives, and fish. These fossils were deposited in a semi-arid to semi-humid environment with meandering rivers.