Cycads are not living fossils? As often claimed?
|November 15, 2011||Posted by News under Intelligent Design, Plants, stasis, News|
Not on this view:
Science 11 November 2011: Recent Synchronous Radiation of a Living Fossil
Modern survivors of previously more diverse lineages are regarded as living fossils, particularly when characterized by morphological stasis. Cycads are often cited as a classic example, reaching their greatest diversity during the Jurassic–Cretaceous (199.6 to 65.5 million years ago) then dwindling to their present diversity of ~300 species as flowering plants rose to dominance. Using fossil-calibrated molecular phylogenies, we show that cycads underwent a near synchronous global rediversification beginning in the late Miocene, followed by a slowdown toward the Recent. Although the cycad lineage is ancient, our timetrees indicate that living cycad species are not much older than ~12 million years. These data reject the hypothesized role of dinosaurs in generating extant diversity and the designation of today’s cycad species as living fossils.
We prefer the term “durable species” to “living fossil”; in any event, if these findings hold up, only the general idea of the cycad is very ancient. But that too is something.
See also Can a creature be a living fossil if it was never a fossil?