The predentary bone is one of the most enigmatic skeletal elements in avian evolution. Located at the tip of the lower jaw, this bone is absent in more primitive birds and in living birds; it is thought to have been lost during evolution. For over 30 years, the origin and function of the avian predentary has remained mysterious.
Click here for original story, New finding on origin of avian predentary in Mesozoic birds
Source: Phys.org