Pinacosaurus

Pinacosaurus Temporal range: Cretaceous, 75–71 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Mounted skeleton cast of Pinacosaurus mephistocephalus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	†Ornithischia
Clade:	†Thyreophora
Clade:	†Ankylosauria
Family:	†Ankylosauridae
Subfamily:	†Ankylosaurinae
Genus:	†Pinacosaurus Gilmore, 1933
Type species
†Pinacosaurus grangeri Gilmore, 1933
Other species
†P.? mephistocephalus Godefroit et al. 1999
Synonyms
Pinacosaurus ninghsiensis Young, 1935 Heishansaurus pachycephalus? Bohlin, 1953 Syrmosaurus viminocaudus Maleev, 1952

Pinacosaurus (meaning "Plank lizard") is a genus of ankylosaurid thyreophoran dinosaur that lived in Asia during the Late Cretaceous (Campanian, roughly 75 to 71 million years ago), mainly in Mongolia and China.

The first remains of the genus were found in 1923, and the type species Pinacosaurus grangeri was named in 1933. Pinacosaurus mephistocephalus named in 1999, is a second possibly valid species differing from the type species in details of the skull armour. At least 24 Pinacosaurus skeletons have been found,^[1] possibly more than of any other ankylosaur. These predominantly consist of juveniles. Adult fossils have not been found in groups.

Pinacosaurus was a medium-sized ankylosaurine, about 5 metres (16 ft) long and weighed up to 1.9 metric tons (2.1 short tons). Its body was flat and low-slung but not as heavily built as in some other members of the Ankylosaurinae. The head was protected by bone tiles, hence its name. Each nostril was formed as a large depression pierced by between three and five smaller holes, the purpose of which is uncertain. A smooth beak bit off low-growing plants that were sliced by rows of small teeth and then swallowed to be processed by the enormous hind gut. Neck, back and tail were protected by an armour of keeled osteoderms. The animal could also actively defend itself by means of a tail club.