Pinacosaurus

Pinacosaurus ("plank lizard") is a genus of medium-sized ankylosaur dinosaurs from the Upper Cretaceous of Mongolia and China. It lived about 80–75 million years ago, and was first found in 1923. 
"Pinacosaurus" had between two and five additional holes near each nostril, which have not been explained.
The animal was a medium-sized ankylosaur, about five metres long, weighing up to two tonnes. Its body was flat and low-slung but not as heavily built as in some other ankylosaurs. 
Its head was protected by bone tiles, hence the name. A smooth beak bit off low-growing plants that were sliced up by rows of small teeth and then swallowed. Food was slowly processed by its enormous hind gut. Neck, back and tail were protected by osteoderms. The animal could also actively defend itself with its tail club.