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Diversification of a New Atlantic Clade of Scleractinian Reef Corals: Insights from Phylogenetic Analysis of Morphologic and Molecular Data
Published online by Cambridge University Press: 21 July 2017
Abstract
Recent molecular analyses of the traditional scleractinian suborder Faviina have revealed a new Atlantic clade of reef corals, which disagrees with traditional classification. The new clade contradicts long-held notions of Cenozoic diversification being concentrated in the Pacific, and of Atlantic species bearing close evolutionary relationships with Pacific species. In the present paper, we outline an approach for integrating molecular, morphologic, and fossil data, which will allow future examination of the timing and phylogenetic context of the divergence of the new Atlantic clade. Our analyses are preliminary and focus on 17 genetically characterized species within the new Atlantic clade. The molecular dataset consists of 630 base pairs from the COI gene and 1143 base pairs from the cytB gene. The morphologic dataset consists of 25 traditional morphologic characters (86 states) in 57 species (23 extant and 32 extinct). Phylogenetic analyses are first performed separately on the molecular and morphologic (extant taxa only) datasets. Subsequent phylogenetic analyses involve adding fossil taxa to the morphologic dataset and performing a combined analysis for extant taxa.
The results of both molecular and morphologic phylogenetic analyses disagree with traditional classification. They also disagree with each other, indicating the two datasets provide different phylogenetic signals and are informative at different taxonomic levels. Molecular trees for the mitochondrial genes analyzed have higher bootstrap support for deeper nodes in the tree; morphologic trees have higher bootstrap support near branch tips. The addition of fossils to the morphologic dataset does not improve resolution within phylogenetic trees, but it does indicate that all of the major subclades within the new Atlantic clade originated prior to middle Eocene time. The pulse of origination associated with Plio-Pleistocene faunal turnover involved speciation within well-established clades. Examination of the geographic distributions of the taxa within each of the four resulting trees indicates that the origin of the Brazilian reef coral fauna involved more than one separate dispersal event or that the fauna may be descended from a larger Mio-Pliocene Atlantic (Caribbean to Brazil) species pool, portions of which have subsequently become extinct. Because of the complex nature of scleractinian evolution (involving possible hybridization), we advocate using a phylogenetic approach that compares multiple independent datasets, including datasets that are currently being developed for new microstructural characters.
- Type
- Research Article
- Information
- The Paleontological Society Papers , Volume 11: Paleobiogeography: Generating New Insights into the Coevolution of the Earth and its Biota , October 2005 , pp. 103 - 128
- Copyright
- Copyright © 2005 by the Paleontological Society
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