title: Palaeobotanical redux: revisiting the age of the angiosperms.
abstract: Angiosperms (flowering plants) are the most diverse of all major lineages of land plants and the dominant autotrophs in most terrestrial ecosystems. Their evolutionary and ecological appearance is therefore of considerable interest and has significant implications for understanding patterns of diversification in other lineages, including insects and other animals. More than half a century ago, influential reviews showed that while angiosperms are richly represented in sediments of Late Cretaceous and younger ages, there are no reliable records of angiosperms from pre-Cretaceous rocks. The extensive new macrofossil, mesofossil, and microfossil data that have accumulated since have confirmed and reinforced this pattern. Recently, however, molecular dating methods have raised the possibility that angiosperms may have existed much earlier, and there have been scattered reports of putative angiosperms from Triassic and Jurassic rocks. Critical assessment of these reports shows that, so far, none provide unequivocal evidence of pre-Cretaceous angiosperms. Angiosperms may ultimately be recognized from Jurassic or earlier rocks, but credible palaeobotanical evidence will require unambiguous documentation of the diagnostic structural features that separate angiosperms from other groups of extant and extinct seed plants.
authors.affiliation: Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, Illinois 60022, USA.
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Herendeen
authors.affiliation: Department of Palaeobiology, Swedish Museum of Natural History, SE-104 05 Stockholm, Sweden.
authors.forename: Else Marie
authors.initials: EM
authors.lastname: Friis
authors.affiliation: Department of Earth Science, University of Aarhus, DK-8000 Aarhus, Denmark.
authors.forename: Kaj Raunsgaard
authors.initials: KR
authors.lastname: Pedersen
authors.affiliation: Oak Spring Garden Foundation, 1776 Loughborough Lane, Upperville, Virginia 20184, USA.|Yale School of Forestry and Environmental Studies, 195 Prospect Street, New Haven, Connecticut 06511, USA.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Crane
mesh_terms: D005075:Biological Evolution; D019143:Evolution, Molecular; D005580:Fossils / Q000033:anatomy & histology*; D019684:Magnoliopsida / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics; D010802:Phylogeny