Tracing the long-term evolution of a species complex: Examples from the Montastraea “annularis” complex

The results show that the Montastraea “annularis” complex originated during late Miocene time, and consisted of >12 species during the Pliocene, with a maximum of 4-5 species co-occurring at any one time. The three modern species do not form a monophyletic group but belong to separate clades within the complex. The ranges of two of the three modern species may extend back to 2.9-3.5 Ma, indicating that they are survivors of the Plio-Pleistocene extinction event in which ∼80% of Caribbean reef coral species became extinct. Morphologic differences among species (disparity) were higher during the Pliocene than they are today.