Late Cretaceous – 76.5 – 75.5 Mya
North America: Montana and Alberta
Length: 6.1 meters (20 feet)
Height: 2.7 meters (9 feet)
Weight: 2,170 kg (4,780 lb)
Monoclonius gets the meaning of its name, single sprout, not from the single nose horn but from the way its teeth grew compared to its relative Diclonius, which meant double sprout. In fact while Monclonius is a member of the group of horned face dinosaurs, when first discovered it was thought to be a hadrosaur when it was unearthed.
There has been much confusion over the assigning of fossils to the Monoclonius genus over the years but it is now acknowledged that all known specimens are of juveniles and sub-adults only. An adult Monoclonius has still to be discovered.