Pinacosaurus

Pinacosaurus was a lightly built, medium-sized ankylosaur that reached a length of 16 ftLike allankylosaurids, it had a bony club at the end of its tail which it used as a defensive weapon against predators such asTarbosaurus. The most unusual element in the original specimen is the presence of two additional egg-shaped holes, one on top of the other, where the nostrils are normally found.[2] The openings are characteristic of the genus, and the number varies: Godefroit et al. described four in 1999, and in 2003 a juvenile specimen with of five pairs of openings was described