Triassic Kykloxylon wood (Umkomasiaceae, Gymnospermopsida) from Skinner Ridge, northern Victoria Land, East Antarctica

• Published in: Review of Palaeobotany and Palynology
• Main Authors: Oh, Changhwan, Park, Tae-Yoon, Woo, Jusun, Bomfleur, Benjamin, Philippe, Marc, Decombeix, Anne-Laure, Kim, Young-Hwan G., Lee, Jong Ik
• Other Authors: Division of Polar Earth-System Sciences, Korea Polar Research Institute (KOPRI), Forschungsstelle für Paläobotanik, Westfälische Wilhelms-Universität Münster = University of Münster (WWU), Department of Palaeobotany, Swedish Museum of Natural History, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Sud ), Polar Science, University of Science and Technology
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Fossil wood Triassic Kykloxylon Umkomasiaceae Skinner Ridge Antarctica; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Antarctic; East Antarctica; Skinner Ridge; Victoria Land; Antarc*; Antarctica
• Online Access: https://sde.hal.science/hal-01369185; https://doi.org/10.1016/j.revpalbo.2016.07.006

International audience During the ␣rst Korea Antarctic Geological Expedition (KAGEX I, 2013/2014), fossil wood was collected from the Triassic ␣uvial deposits of the Beacon Supergroup at Skinner Ridge in northern Victoria Land, Antarctica. The material is coali␣ed and partially silici␣ed; most specimens are slightly compressed due to burial compaction. In spite of this imperfect preservation, anatomical features of both the xylem and the pith could be observed in some specimens. The xylem displays prominent growth rings and usually araucarioid or somewhat mixed- type radial pitting with some abnormal rings partly composed of parenchymatous tissues. Some specimens also have a wood cylinder that is divided radially by parenchymatous zones. These anatomical features indicate a systematic af␣nity with Kykloxylon Mey.-Berth., T.N.Taylor et Ed.L.Taylor, a characteristic wood type of the Umkomaciaceae, which ␣ourished throughout Gondwana during the Triassic. The Kykloxylon specimens in this study represent the only wood fossil taxon in the Triassic of Victoria Land, except for a dubious report of Antarcticoxylon Seward in 1914. This may indicate a low diversity of Triassic wood fossils in this area, as in other parts of Antarctica. On the contrary, diverse other gymnosperm organs are known to occur in the Triassic of Antarctica. This low diversity of wood taxa compared to the various plant organs in the Triassic of Antarctica is remarkable. We hypothesize three major reasons for this: 1) the overall structural uniformity of gymnosperm wood compared to other vegetative and especially reproductive organ diversity; 2) the overwhelming dominance of corystosperm plants, with a minor component of voltzialean conifers in the canopy-forming forest vegetation during the Triassic in Antarctica; and 3) the very few systematic studies of fossil wood compared to other plant macrofossils.