Yes because the Mesozoic is a geological era.
The Mesozoic is a geological era containing 3 periods: Triassic (251 - 201 MYA), Jurassic (201 - 145 MYA), and the Cretaceous (145 - 66 MYA) The Mesozoic lasted 251 to 66 million years ago.
MYA is short for million years ago.