Anatomically preserved Dicroidium foliage from the central transantarctic mountains

摘要: Abstract The first anatomically preserved species of Dicroidium, D. fremouwensis Piggs sp. nov. is described from the Triassic central Transantarctic Mountains, Antarctica. Dicroidium has pinnules that ranges entire-margined to highly lobed morphologies. Entire-margined occur basally and become progressively more dissected at distal levels frond. most similar compression-impression forms dubium var. (Feistmantel) Retallack tasmaniense (Anderson et Anderson) Retallack. Fronds also bear some resemblance sp cf. feistmantelii sensu Lele, Gothan (Johnston) Gothan. Distal frond bifurcation, pinna rachides have a dorsiventral vascular anatomy composed an abaxial ring six eight bundles adaxial linear group five bundles. Bundles line produce lateral strands vascularize laminar pinnules, while remain in diminishes three distally. Pinnules odontopterid venation, differentiated mesophyll, resinous cells transfusin tracheids. organization other anatomical features are those fronds extant cycads. This information provides new level resolution our knowledge documents how permineralized fossils promise refine understanding complex Mesozoic gymnosperms.