Article: A phylogenetic test of accelerated turnover in Neogene Caribbean brain corals (Scleractinia: Faviidae)
Kenneth G. Johnson
Documenting patterns of long-term faunal change is an important application of palaeontological data, but questionable results may be obtained if the potential effects of sampling bias are not considered. Analysis of fossil Caribbean reef coral occurrences indicates significant species turnover during the late Neogene. The goal of this study is to test this pattern for a subset of the entire fauna by using phylogenetic information to identify problematical taxa and periods of poor sampling. A phylogeny for 40 species from the faviid genera Caulastraea, Colpophyllia, Diploria, Favia, Hadrophyllia, Manicina and Thysanus was inferred using 23 multistate characters. Although the relationships are homoplasious, some stable groups emerged. One group includes the Colpophyllia species, another includes Manicina, Hadrophyllia and Thysanus species. As currently defined, both Favia and Diploria are paraphyletic stem groups. The inferred evolutionary tree was used to estimate species richness and proportional origination and extinction rates. When ghost lineages are considered, the magnitude of species richness estimates increases resulting in lower estimates of proportional origination and extinction. However, the pattern of faunal change within the group remains largely unchanged, with increased origination during the Late Miocene followed by extinction during the Late Pliocene and early Pleistocene.