Monkonosaurus (meaning "Monkon lizard") is a dubious genus of herbivorous stegosaurian dinosaur from the Late Jurassic (Kimmeridgian stage, around 150-155 million years ago) of Tibet.
The genus was formalized by Zhao Xijin in 1983. The generic name refers to Markam County, also known as Monko.[1] Zhao at the time gave neither a description, meaning the name remained a nomen nudum, nor a specific name. The latter was provided in 1986 when the type species Monkonosaurus lawulacus was named, the epithet referring to the Lawushan, the Lawu mountains. The first description was provided in 1990 by Dong Zhiming.[2]
The holotype, IVPP V 6975, was found in a layer of the Lura Formation dating from the latest Jurassic. It consists of partial skeleton lacking the skull. It contains a pelvis with sacrum, two vertebrae and three back plates. The fragmentary condition of this single skeleton places doubt on the validity of this genus, some studies concluding it is a nomen dubium.[3]
Monkonosaurus was about five metres long. The ilium has a length of 905 millimetres. The sacrum consists of five sacral vertebrae.[2]
Zhao placed Monkonosaurus in the Oligosacralosauroidea. Later researchers considered it an indeterminate member of the Stegosauridae.