Here we report on angiosperm-like pollen and Afropollis from the Anisian (Middle Triassic, 247.2–242.0 Ma) of a mid-latitudinal site in Northern Switzerland. Small monosulcate pollen grains with typical reticulate (semitectate) sculpture, columellate structure of the sexine and thin nexine show close similarities to early angiosperm pollen known from the Early Cretaceous. However, they differ in their extremely thin inner layer (nexine). Six different pollen types (I–VI) are differentiated based on size, reticulation pattern, and exine structure. The described pollen grains show all the essential features of angiosperm pollen. However, considering the lack of a continuous record throughout the lower part of the Mesozoic and the comparison with the oldest Cretaceous finds we suggest an affinity to an angiosperm stem group. Together with the previously published records from the Middle Triassic of the Barents Sea area the angiosperm-like pollen grains reflect a considerable diversity of the parent plants during the Middle Triassic. Sedimentological evidence and associated palynofloras also suggest a remarkable ecological range for these plants. Associated with these grains we found pollen comparable to the genus Afropollis. Representatives of this genus are commonly recorded in Lower Cretaceous sediments of low latitudes, but until now had no record from the lower part of the Mesozoic.
Keywords: Middle Triassic, angiosperm-like pollen, angiosperm stem group, Afropollis, confocal laser scanning microscopy
Citation: Hochuli PA and Feist-Burkhardt S (2013) Angiosperm-like pollen and Afropollis from the Middle Triassic (Anisian) of the Germanic Basin (Northern Switzerland). Front. Plant Sci. 4:344. doi: 10.3389/fpls.2013.00344
Received: 31 May 2013; Accepted: 15 August 2013;
Published online: 01 October 2013.
Edited by:Xin Wang, Chinese Academy of Sciences, China
Reviewed by:Michael S. Zavada, Seton Hall University, USA
Copyright © 2013 Hochuli and Feist-Burkhardt. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Peter A. Hochuli, Palaeontological Institute and Museum, University of Zürich, Karl-Schmid-Strasse 4, Zürich, CH-8006, Switzerland e-mail: firstname.lastname@example.org