Seyfullah, Leyla J. , Hilton, Jason , Galtier, Jean .
Callistophytalean pteridosperms from the Permian of China.
Recent investigations have highlighted the widespread occurrence of Callistophytalean pteridosperms within the Permian floras of China that challenge previous ideas concerning their spatial and temporal distributions. In China Callistophytales range from the Late Pennsylvanian through to the Late Permian and constitute a rare but important component in many coal-forming environments. The stratigraphically earliest Callistophytalean occurs in the Late Pennsylvanian (Late Moscovian) Benxi Formation of North China in which rare but distinctive foliar remains have been identified. Early Permian aged coal balls from the Taiyuan Formation of northern China contain permineralized Callistophytalean assignable to Callospermarion Eggert and Delevoryas. More abundant in the fossil records is adpressed foliage of Emplectopteris Halle from the late Early – Middle Permian aged Lower Shihhotse Formation of Northern China. Emplectopteris demonstrates features consistent with known Callistophytaleans including gross morphology with bifurcating rachises, venation patterns and distinctive glandular bodies on the surface of foliage and ovules, and is here reinterpreted as a Callistophytalean. The Shihhotse Formation also contains presently unnamed species in which pollen organs and ovules are born abaxially over pinnule veins on typical Callistophytalean foliage. The youngest Callistophytaleans so far identified are stems referable as Callistophyton from the Late Permian Xuanwei Formation of southern China. Collectively these accounts are augmented by analysis of pollen records that demonstrate the Callistophytalean sporae-dispersae genus Vesicaspora Schemel to be widespread through the Early Permian of northern China and the Late Permian of southern China. Although specimens are typically rare elements in the assemblages that contain them, they demonstrate continuity of Callistophytalean pteridosperms throughout the Late Pennsylvanian into the early Late Permian in the northern China, and into the Late Permian of southern China. The presence of Vesicaspora is a hopeful indicator that more Callistophytalean pteridosperms are yet to be found.
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1 - University of Birmingham, Earth Sciences, School of Geography, Earth and Environmental Science, Edgbaston, Birmingham, B15 2TT, U.K.
2 - CIRAD, UMR5120, Botanique & Bioinformatique, TA40/ PS2, Bouleverd de la Lironde, Montpellier, 34398, France
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 9:15 AM