New insights into the anatomy, development, and affinities of corystosperm trees from the Triassic of Antarctica

• Published in: Review of Palaeobotany and Palynology
• Main Authors: Decombeix, Anne-Laure, Bomfleur, Benjamin, Taylor, Edith L., Taylor, Thomas N.
• Other Authors: Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD France-Sud ), Department of Ecology and Evolutionary Biology, University of Kansas, University of Kansas Lawrence (KU), National Science Foundation (grant OPP-10943934 to ELT and TNT), Alexander von Humboldt-Foundation (Feodor Lynen fellowship to BB)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: secondary growth; Kykloxylon; Jeffersonioxylon; Triassic; Antarctica; Corystospermales; [SDV]Life Sciences [q-bio]; [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE]; [SDE]Environmental Sciences; Beardmore; Beardmore Glacier; Fremouw Peak; Gordon Valley; Antarc*
• Online Access: https://hal.archives-ouvertes.fr/halsde-00961820; https://doi.org/10.1016/j.revpalbo.2014.01.002

International audience Anatomically preserved trunks and young stems of corystosperm seed ferns are described from the Triassic of Fremouw Peak, Beardmore Glacier area, Antarctica. Based on characters of the primary and secondary vascular system, these new specimens are assigned to Kykloxylon, a genus that was established based on young stems with attached Dicroidium leaf bases. The largest specimens illustrate how some secondary growth characters, such as unequal cambial activity, appeared during later development, which enables a better comparison of Kykloxylon with trunks assigned to other corystosperm genera. Jeffersonioxylon from the Gordon Valley, Antarctica, and Cuneumxylon from South America show strong similarities with the newly described larger Kykloxylon trunks from Fremouw Peak, and might be considered congeneric. Our results provide further support for the presence of two anatomically and morphologically distinct kinds of Dicroidium-bearing trees in the Triassic vegetation of Gondwana, one with a palm-like habit and Rhexoxylon stems and the other with a more Ginkgo-like habit and Kykloxylon/Cuneumxylon-type stems