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Silurian-Devonian Biogeography |
Department of Geology, University of Alabama, Tuscaloosa, Alabama 35487-0338, USA
Stromatoporoids were a common component of shallow carbonate environments of North America, Eurasia, and Australia during the Devonian. They were least abundant during the Early Devonian. After that time abundance increased, and remained high steadily through the Frasnian. At the Frasnian-Famennian boundary the number of stromatoporoids was greatly diminished, but they did not become extinct until the end of the Devonian (at the end of the Strunian). The geographic extent of stromatoporoids expanded and contracted concurrently with increases and decreases in total population size. Provincialism at the genus level prevailed during the Early Devonian, with stromatoporoids inhabiting the Old World and Eastern Americas Realms; none are known from the Eastern Americas during the Siegenian. For the remainder of the Devonian stromatoporoids were cosmopolitan at the genus level. The abundance of stromatoporoids varied directly with eustatic sea level during the Devonian. Variations in depositional conditions apparently controlled the local distribution of genera.
