Which of the following fish is a living fossil?

Latimeria is a bony fish belonging to the subclass Crossopterygii. It is the sole sur­viving representative of the coelacanths. 

Latimeria is known as a living fossil because its morphology has remained unchanged for hundreds of millions of years. While they share many characteristics with the other Osteichthyes like the skeletal system and a diphycercal tail, they are distinct.