2011/10/21 by Nathalie S. Nagalingum, Charles R. Marshall, Tiago B. Quental +3 · 9 citations
Agricultural and Biological Sciences · #Botany and Geology in Latin America and Caribbean #Plant and animal studies #Plant Diversity and Evolution
paper · doi:10.1126/science.1209926
openalex publication_date 2011/10/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
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.