Diversity and extinction in the Cenozoic history of Caribbean reefs |
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Authors: | A F Budd |
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Institution: | (1) Department of Geoscience, University of Iowa, Iowa City, IA 52242, USA e-mail: ann-budd@uiowa.edu Fax: +1-319-3351821, US |
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Abstract: | Occurrences of reef corals are examined at Caribbean fossil localities to determine how biodiversity has changed within the
region over the past 50 million years. Analyses of 294 species (66 genera) at 58 fossil localities show that Caribbean generic
diversity rose to 44 between 50–22 Ma, ranged from 32–39 between 22–2 Ma, and dropped to 25 afterwards. Regional species diversity
was high at 40–36 Ma, 28–22 Ma, and 5–2 Ma. Origination rates were elevated throughout each high diversity interval, but extinction
was concentrated near the end of each interval. Regional highs of origination and extinction, therefore, differed in timing
and duration, causing the observed regional diversity increases during the three remarkably long intervals of turnover. Highs
of generic origination decreased in magnitude as immigration from the Mediterranean ceased, but speciation highs increased
in association with emergence of the Central American isthmus. Peaks of extinction coincided with regional changes in climate
and oceanic circulation.
Maximum species diversities within assemblages increased to 40–60 between 50–36 Ma, and have remained relatively constant
ever since. Assemblage compositions differed among localities having similar ages and environments, suggesting that the timing
and pattern of turnover varied across the region. Stable diversities but variable compositions within assemblages suggest
that dispersal and recruitment influenced the pattern of faunal change during turnover.
Accepted: 22 August 1999 |
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Keywords: | Cenozoic Caribbean Reef corals Biodiversity Extinction |
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