Evidence for a Cenozoic strongradiationstrong of ferns in an angiosperm.pdfVIP

Evidence for a Cenozoic radiation of ferns in an angiosperm-dominated canopy Eric Schuettpelz1 and Kathleen M. Pryer Department of Biology, Duke University, Durham, NC 27708 Edited by Peter R. Crane, University of Chicago, Chicago, IL, and approved May 27, 2009 (received for review November 3, 2008) In today’s angiosperm-dominated terrestrial ecosystems, leptospo- that the bulk of polypod diversity arose following the rise of rangiate ferns are truly exceptional—accounting for 80% of the flowering plants (15). Subsequent divergence-time estimates 11,000 nonflowering vascular plant species. Recent studies have suggested that this pattern of recent diversification—in the shown that this remarkable diversity is mostly the result of a major shadow of angiosperms—might be echoed in other leptospor- leptosporangiate radiation beginning in the Cretaceous, following angiate orders (16). Thus, it appears that the remarkable diver- the rise of angiosperms. This pattern is suggestive of an ecological sity of leptosporangiate ferns on Earth today is not simply the opportunistic response, with the proliferation of flowering plants result of being adept at holding on in the face of angiosperm across the landscape resulting in the formation of many new domination. Rather, it seems that ferns may have somehow been niches—both on forest floors and within forest canopies—into able to capitalize upon it. which leptosporangiate ferns could diversify. At present, one-third One plausible explanation for the success of leptosporangiates of leptosporangiate species grow as epiphytes in the canopies of involves an ecological opportunistic response to the rise of angiosperm-dominated tropical rain forests. However,