Polycotylidae - Museum of the Rockies
Polycotylidae fossil on display at the Museum of the Rockies in Bozeman, Montana.
This specimen was found in 1991 near Billings, Montana.
Polycotylidae are one of two families of plesiosaurs. Cryptoclididae had long necks, and broad, short skulls densely packed teeth. Polycotylidae had short necks, and narrow, long skulls fitted with more needle-like teeth. They first appeared about 129 million years ago, and died out about 72 million years ago -- replaced by mosasaurs.
So much of this fossil skeleton is missing that it has proven impossible to determine exactly which kind of Polycotylidae this is.
Polycotylidae - Museum of the Rockies
Polycotylidae fossil on display at the Museum of the Rockies in Bozeman, Montana.
This specimen was found in 1991 near Billings, Montana.
Polycotylidae are one of two families of plesiosaurs. Cryptoclididae had long necks, and broad, short skulls densely packed teeth. Polycotylidae had short necks, and narrow, long skulls fitted with more needle-like teeth. They first appeared about 129 million years ago, and died out about 72 million years ago -- replaced by mosasaurs.
So much of this fossil skeleton is missing that it has proven impossible to determine exactly which kind of Polycotylidae this is.