Mantis Shrimp and their evolution is a controversial topic. Many scientists believe that Mantis Shrimp are virtually unchanged over many time periods.  Some Scientists refer to them as prime examples of "living fossils." (1)

 

Most scientists agree that they have changed since the Devonian time period, this is when Mantis Shrimp diverged from other crustaceans.(1)

 

The photo below compares a Mantis Shrimp from 350 million years ago, to today's Mantis Shrimp.(1)