The type (and only known) specimen was found in the summer of 2000 by a Chinese-American expedition in the Mazong (= "horse mane") Shan area of China's Gansu Province.[1] In 2002 You Hialu in a dissertation named and described the species Equijubus normani. The generic name is derived from Latinequus, "horse", and juba, "mane". The specific epithet "normani" is in honour of BritishpalaeontologistDavid B. Norman.[2] However, such a nomen ex dissertatione does not constitute a valid name.
Wu, You & Li (2018) described grass microfossils extracted from a specimen of Equijubus normani, which at the time of their description were the oldest known grass fossils, and might be the oldest known evidence of a dinosaur feeding on grasses, implying that it was most likely a grazer.[3]
Description
Teeth of the holotype
Equijubus is a relatively large euornithopod. Gregory S. Paul in 2010 estimated the length at seven metres, the weight at 2.5 tonnes.[4] A palpebral bone seems to be absent, meaning the eyes were not overshadowed by an upper rim as with most related species.
Phylogeny
Equijubus was described as a basal hadrosauroid dinosaur, although it may turn out to be a non-hadrosauroid iguanodont. The discoverers considered it to be the basal-most of the hadrosauroids, and suggested that this group emerged in Asia.[1]
^ abcdYou, Luo, Shubin, Witmer, Tang and Tang (2003). "The earliest-known duck-billed dinosaur from deposits of late Early Cretaceous age in northwest China and hadrosaurid evolution." Cretaceous Research, 24: 347-353.
^You Hailu, 2002, Mazongshan dinosaur assemblage from late Early Cretaceous of northwest China. Dissertation University of Pennsylvania 164 pp
