title: Ectomycorrhizas from a Lower Eocene angiosperm forest.
abstract: The development of mycorrhizal associations is considered a key innovation that enabled vascular plants to extensively colonize terrestrial habitats. Here, we present the first known fossil ectomycorrhizas from an angiosperm forest. Our fossils are preserved in a 52 million-yr-old piece of amber from the Tadkeshwar Lignite Mine of Gujarat State, western India. The amber was produced by representatives of Dipterocarpaceae in an early tropical broadleaf forest. The ectomycorrhizas were investigated using light microscopy and field emission scanning electron microscopy. Dissolving the amber surrounding one of the fossils allowed ultrastructural analyses and Raman spectroscopy. Approx. 20 unramified, cruciform and monopodial-pinnate ectomycorrhizas are fossilized adjacent to rootlets, and different developmental stages of the fossil mycorrhizas are delicately preserved in the ancient resin. Compounds of melanins were detectable in the dark hyphae. The mycobiont, Eomelanomyces cenococcoides gen. et spec. nov., is considered to be an ascomycete; the host is most likely a dipterocarp representative. An early ectomycorrhizal association may have conferred an evolutionary advantage on dipterocarps. Our find indicates that ectomycorrhizas occurred contemporaneously within both gymnosperms (Pinaceae) and angiosperms (Dipterocarpaceae) by the Lower Eocene.
authors.affiliation: Courant Research Centre Geobiology, Georg-August-Universität Göttingen, Goldschmidtstraße 3, 37077 Göttingen, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Beimforde
authors.affiliation: Courant Research Centre Geobiology, Georg-August-Universität Göttingen, Goldschmidtstraße 3, 37077 Göttingen, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Schäfer
authors.affiliation: Mikrobielle Phytopathologie, Friedrich-Schiller-Universität Jena, Neugasse 25, 07743 Jena, Germany.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Dörfelt
authors.affiliation: Division of Invertebrate Zoology, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024, USA.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Nascimbene
authors.affiliation: Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow 226007, India.
authors.forename: Hukam
authors.initials: H
authors.lastname: Singh
authors.affiliation: Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Abteilung Systematische Botanik, Georg-August-Universität Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Heinrichs
authors.affiliation: Courant Research Centre Geobiology, Georg-August-Universität Göttingen, Goldschmidtstraße 3, 37077 Göttingen, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Reitner
authors.affiliation: Department of Geology, Hemwati Nandan Bahuguna Garhwal University, Srinagar 246174, India.
authors.forename: Rajendra S
authors.initials: RS
authors.lastname: Rana
authors.affiliation: Courant Research Centre Geobiology, Georg-August-Universität Göttingen, Goldschmidtstraße 3, 37077 Göttingen, Germany.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Schmidt
mesh_terms: D005580:Fossils; D019684:Magnoliopsida / Q000382:microbiology*; D025282:Mycelium / Q000166:cytology; D038821:Mycorrhizae / Q000145:classification / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D013059:Spectrum Analysis, Raman; D013997:Time Factors; D014197:Trees / Q000382:microbiology*
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