title: The presumed ginkgophyteUmaltolepishas seed-bearing structures resembling those of Peltaspermales and Umkomasiales.
abstract: The origins of the five groups of living seed plants, including the single relictual speciesGinkgo biloba, are poorly understood, in large part because of very imperfect knowledge of extinct seed plant diversity. Here we describe well-preserved material from the Early Cretaceous of Mongolia of the previously enigmatic Mesozoic seed plant reproductive structureUmaltolepis, which has been presumed to be a ginkgophyte. Abundant new material shows thatUmaltolepisis a seed-bearing cupule that was borne on a stalk at the tip of a short shoot. Each cupule is umbrella-like with a central column that bears a thick, resinous, four-lobed outer covering, which opens from below. Four, pendulous, winged seeds are attached to the upper part of the column and are enclosed by the cupule. Evidence from morphology, anatomy, and field association suggests that the short shoots bore simple, elongatePseudotorellialeaves that have similar venation and resin ducts to leaves of livingGinkgoUmaltolepisseed-bearing structures are very different from those ofGinkgobut very similar to fossils described previously asVladimaria. UmaltolepisandVladimariado not closely resemble the seed-bearing structures of any living or extinct plant, but are comparable in some respects to those of certain Peltaspermales and Umkomasiales (corystosperms). Vegetative similarities of theUmaltolepisplant toGinkgo, and reproductive similarities to extinct peltasperms and corystosperms, support previous ideas thatGinkgomay be the last survivor of a once highly diverse group of extinct plants, several of which exhibited various degrees of ovule enclosure.
authors.affiliation: Chicago Botanic Garden, Glencoe, IL 60022.
authors.forename: Fabiany
authors.initials: F
authors.lastname: Herrera
authors.affiliation: Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.
authors.forename: Gongle
authors.initials: G
authors.lastname: Shi
authors.affiliation: Institute of Paleontology and Geology, Mongolian Academy of Sciences, Ulaanbaatar-51, Mongolia.
authors.forename: Niiden
authors.initials: N
authors.lastname: Ichinnorov
authors.affiliation: Department of Environmental Sciences, Faculty of Sciences, Niigata University, Ikarashi, Nishi-ku, Niigata 950-2181, Japan.
authors.forename: Masamichi
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Institute of Biology and Soil Science, Far East Branch, Russian Academy of Sciences, Vladivostok 690022, Russia.
authors.forename: Eugenia V
authors.initials: EV
authors.lastname: Bugdaeva
authors.affiliation: Chicago Botanic Garden, Glencoe, IL 60022.
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Herendeen
authors.affiliation: School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511; peter.crane@yale.edu.|Oak Spring Garden Foundation, Oak Spring, Upperville, VA 20184.
authors.forename: Peter R
authors.initials: PR
authors.lastname: Crane
mesh_terms: D005580:Fossils / Q000033:anatomy & histology; D020441:Ginkgo biloba / Q000033:anatomy & histology* / Q000145:classification; D010944:Plants / Q000033:anatomy & histology* / Q000145:classification; D012639:Seeds / Q000033:anatomy & histology* / Q000145:classification
keywords: Cretaceous; Ginkgo; Mongolia; Umaltolepis