Eocene Caribbean Reef Corals - a Unique Fauna from the Gatuncillo Formation of Panama

Forty-three species of 25 genera are described in a collection of 170 large, massive reef corals from the upper Eocene Gatuncillo Formation near Lago Alahuela in central Panama. Comparisons with type material for other Eocene Caribbean reef corals suggest that 27 of these species are new. Twenty-four of these species are named herein. Like other Eocene Caribbean reef-coral faunas, the fauna is rich in Astrocoenia, Actinacis, and Astreopora; however, unlike other faunas, plocoid and meandroid members of the family Faviidae (e.g., Montastraea, Agathiphyllia, Goniastrea, and Colpophyllia) are abundant. Also present are the oldest known representatives of the genera Meandrina, Coscinaraea, Alveopora, Heliopora, and Pocillopora, as well as the only recorded occurrences of Coscinaraea and Cyathoseris from the Caribbean. Comparisons with Oligocene and Recent Caribbean reef-coral faunas suggest that the generic composition of Cenozoic Caribbean reefs became established during the Eocene. With exception of the family Mussidae, much of the post-Oligocene history of the Caribbean is one of extinction at the generic level (19 of the 28 Eocene genera became extinct) and proliferation of species within the surviving genera.