Agathoxylon (also known by the synonyms Dadoxylon and Araucarioxylon) is a form genus of fossil wood, including massive tree trunks. Although identified from the late Palaeozoic to the end of the Mesozoic, Agathoxylon is common from the Carboniferous to Triassic. Agathoxylon represents the wood of multiple conifer groups, including both Araucariaceae and Cheirolepidiaceae, with late Paleozoic and Triassic forms possibly representing other conifers or other seed plant groups like "pteridosperms".
Description
Agathoxylon were large trees that bore long strap-like leaves and trunks with small, narrow rays. Often the original cellular structure is preserved as a result of silica in solution in the ground water becoming deposited within the wood cells. This mode of fossilization is termed permineralization.
Systematics
As a genus, Dadoxylon was poorly defined, and apart from Araucariaceae, has been associated with fossil wood as diverse as Cordaitales, Glossopteridales and Podocarpaceae. Furthermore, it may be the same form genus as Araucarioxylon, hence the usage Dadoxylon (Araucarioxylon). The genus Agathoxylon, classified under the familyAraucariaceae, has nomenclatural priority over the genera Araucarioxylon and Dadoxylon.
Several Dadoxylon species, such as D. brandlingii and D. saxonicum have been identified as Araucarites. D. arberi and D. sp.1 were synonymised with the glossopterid species Australoxylon teixterae and A. natalense, respectively; while D. sp. 2 was transferred to Protophyllocladoxylon.
Agathoxylon pseudoparenchymatosum (Gothan 1908) Pujana et al. 2014 [=Araucarioxylon chilense, A. kerguelense, A. novaezeelandii, A. pseudoparenchymatosum, Dadoxylon kaiparaense, D. kergulense, D. pseudoparenchymatosum]: Santa Marta Formation, Antarctica
Agathoxylon santacruzense Kloster and Gnaedinger 2018: La Matilde Formation, Argentina
Agathoxylon santalense (Sah & Jain): La Matilde Formation, Argentina
↑Torrey, R. E. (1923). "The comparative anatomy and phylogeny of the Coniferales Part 3: Mesozoic and Tertiary coniferous woods". Proceedings and Transactions of the Royal Society of Canada. 3. Vol.6. Memoirs of the Boston Society of Natural History. pp.38–103.
↑Giraud, Bernadette (1991). "Les espèces du genre Dadoxylon depuis 1962: Leur répartition et leur évolution du Permien à la fin du Mésozoïque". Review of Palaeobotany and Palynology. 67 (1–2): 13–39. Bibcode:1991RPaPa..67...13G. doi:10.1016/0034-6667(91)90014-T.
12Mencl, Václav; Matysová, Petra; Sakala, Jakub (2009). "Silicified wood from the Czech part of the Intra Sudetic Basin (Late Pennsylvanian, Bohemian Massif, Czech Republic): Systematics, silicification and palaeoenvironment". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 252 (3): 269. Bibcode:2009NJGPA.252..269M. doi:10.1127/0077-7749/2009/0252-0269.
↑Pujana, R. R., Wilf, P., & Gandolfo, M. A. (2020). Conifer wood assemblage dominated by Podocarpaceae, early Eocene of Laguna del Hunco, central Argentinean Patagonia. PhytoKeys, 156, 81–102. https://doi.org/10.3897/phytokeys.156.54175
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