• Two new genera and species of conifers d

    From ScienceDaily@1:317/3 to All on Tue Aug 3 21:30:40 2021
    Two new genera and species of conifers discovered from upper Cretaceous
    in Hokkaido, Japan

    Date:
    August 3, 2021
    Source:
    Perot Museum of Nature and Science
    Summary:
    Paleobotanists describe two new genera of ancient conifers based
    on two beautifully preserved 3-D fossil seed cones. These new
    conifers belong to the cypress family, which was important in many
    ecosystems during the age of dinosaurs.



    FULL STORY ========================================================================== Illustrations depicting the dinosaur era -- whether in books or movies
    -- are often accompanied by lush greenery. And during the Cretaceous
    period, the trees commonly dominating a wide range of Earth's terrestrial environments were conifers -- similar to the pines, spruces cypresses
    and cedars that populate the earth today. These conifers played a key
    role in ecosystems, providing nourishment, nutrients, and habitat for
    a range of prehistoric creatures.


    ==========================================================================
    In a recently published paper, a team of American paleobotanists describe
    two new genera of ancient conifers based on two beautifully preserved
    3-D fossil seed cones. The scientific paper describing the find -- titled "Ancient diversity and turnover of cunninghamioid conifers (Cupressaceae):
    two new genera from the Upper Cretaceous of Hokkaido, Japan" -- has been published online in the scientific journal, Botany. Co-authors of the
    report are Brian A.

    Atkinson, Ph.D., assistant professor at University of Kansas and
    curator of paleobotany at the Biodiversity Institute, Lawrence, Kan.;
    Dori L. Contreras, Ph.D., curator of paleobotany, Perot Museum of
    Nature and Science, Dallas, Texas; Ruth A. Stockey, Ph.D., professor,
    Oregon State University, Corvallis, Ore.; and Gar W. Rothwell, Ph.D., distinguished professor emeritus, Ohio University, Athens, Ohio.

    The fossils are named Ohanastrobus hokkaidoensis and Nishidastrobus
    japonicumin honor of Tamiko Ohana (National Museum of Nature and Science, Tsukuba, Japan) and Professor Harufumi Nishida (Chuo University, Hachioji, Japan) for their contributions to paleobotany.

    These cones belong to the Cupressaceae (cypress) family, which
    was widespread and important in many ecosystems during the age of
    dinosaurs. This is especially true for one of the oldest lineages
    of family -- the cunninghamioids. The two new genera show that
    cunninghamioids had very diverse forms and were particularly important components of Cretaceous ecosystems of eastern Asia.

    "What's interesting about these two new genera, specifically, is that
    they represent part of the last heyday of cunninghamioids before the
    group's diversity declined toward the end of the Cretaceous," said
    Contreras. "Today we are left with only one living genus, Cunninghamia,
    which are large evergreen trees that grow in the forests of China,
    Taiwan, Vietnam, and Laos." The two new cones showed combinations of
    unique features that indicated they were different from each other and
    all previously known species, therefore they have been named as two new
    genera. Differences include their more cylindrical shape compared to
    the modern Cunninghamiaand most other extinct genera, the number and
    form of their cone scales, and many aspects of their internal anatomy.

    How the discoveries were unearthed and analyzed The cones come from the Cretaceous of Japan and are permineralizations, a type of fossil which preserves all the details of the cells that make up the cones.

    To study them, the team of paleobotanists used a method called the
    cellulose acetate peel technique. The fossils are originally cut with
    a rock saw in two halves vertically to get a "longitudinal section"
    and then cut perpendicular to that to get a "cross section" (see image).

    The cut surfaces are polished and then etched with an acid. A sheet of
    acetate film is placed on the surface with acetone, which adheres to the
    fossil surface. The film is then removed, leaving a microscopically thin
    peel of the fossil specimen attached to the film. The process is repeated
    so that the successive peel slices can be studied under microscopes to understand the three-dimensional anatomy of the specimens and describe
    them in detail.

    As part of their findings, the research team analyzed and compiled
    the records of all cunninghamioid and similar conifers to understand
    how their diversity has changed through time. They show that during
    the Jurassic to Cretaceous there was a much greater diversity of this
    important group of conifers, both by the number of different genera (at
    least 12 fossil genera compared to only one living genus!) and species,
    and by the variation in the form of their cones.

    The living genus Cunninghamia appears during the Campanian and maintains
    a nearly continuous fossil record through to today, while nearly all
    other extinct genera of cunninghamioid Cupressaceae disappear by the
    close of the Campanian (~72 million years ago).

    The two new species expand the known diversity of the cunninghamioids
    before their decline toward the end of the Cretaceous and further
    demonstrate the importance of these conifers in Cretaceous ecosystems, particularly in eastern Asia.

    ========================================================================== Story Source: Materials provided by
    Perot_Museum_of_Nature_and_Science. Note: Content may be edited for
    style and length.


    ========================================================================== Journal Reference:
    1. Brian A. Atkinson, Dori L. Contreras, Ruth A. Stockey, Gar
    W. Rothwell.

    Ancient diversity and turnover of cunninghamioid conifers
    (Cupressaceae): two new genera from the Upper Cretaceous
    of Hokkaido, Japan. Botany, 2021; 99 (8): 457 DOI:
    10.1139/cjb-2021-0005 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2021/08/210803121258.htm

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