Yinlong

Type Species: Yinlong downsi

Classification: Dinosauria - Ornithischia - Ceratopsia 

Time Period: Late Jurassic

Location: China

Diet: Herbivore   

Yinlong was a basal ceratopsian, and along with Hualianceratops is one of the oldest and most primitive known ceratopsians. It was a small, primarily bipedal herbivore that reached just four feet snout-to-tail. It probably weighed around thirty-three pounds. Its hind limbs were long and robust, while its slender forelimbs were shorter and capped with three-fingered hands. Its lifestyle likely mimicked that of early small ornithopods, and it was preserved with seven gastroliths in the abdominal cavity (gastroliths have also been found in the early ceratopsian Psittacosaurus and are present in many of the larger, more derived ceratopsians of the Cretaceous). Despite a virtually frill-less and hornless skull, Yinlong was a ceratopsian. Its skull was deep and wide and relatively large compared to most ornithischians, though it was proportionally smaller than other ceratopsians. The skull has a small rostral bone – in other words, a beak – that is indicative of the ceratopsian lineage. Its squamosal skull orientation is shared by the pachycephalosaurs, indicating that they and ceratopsians shared common direct ancestors. Most interesting of all, Yinlong’s skull has heterodontosaur features, suggesting that the marginocephalians (to which ceratopsians and pachycephalosaurs belong) were more closely related to them than to earlier ‘ornithopod-like’ ornithischians. 

a group of Yinlong clamber about the bones of a sauropod