Two new isoetalean (Lycopsida) megaspore species representing the earliest occurrence of Henrisporites from upper Permian strata of Southwest ChinaShow others and affiliations
2023 (English)In: Review of Palaeobotany and Palynology, ISSN 0034-6667, E-ISSN 1879-0615, Vol. 314, article id 104894Article in journal (Refereed) Published
Abstract [en]
Two distinctive lycopsid megaspore species, Henrisporites yunnanensis Sui, McLoughlin et Feng sp. nov. and H. qujingensis Sui, McLoughlin et Feng sp. nov., are described from the Lopingian Xuanwei Formation of Yunnan Province, Southwest China, using scanning and transmission electron microscopy. Henrisporites yunnanensis is characterized by prominent membranous triradiate labra with ragged margins, a broad irregularly serrated membranous zona with radiating spiny extensions, and ramified or unbranched spines on the spore surface, those on the distal surface especially having capillate termini. Punctatisporites-type microspores occur adhering to the megaspore surface. The megaspore wall incorporates four layers, viz., from inside to outside: (1) a thin and dense foot layer especially thickened at the laesurae lips; (2) a moderately-thick layer with small circular and loosely distributed sporopollenin grains with parallel arrangement; (3) a thick spongy layer consisting ofelongate, curved and interconnected sporopollenin units perpendicular to the inner layers; and (4) an electron-dense outermost layer forming the ornamentation. Henrisporites qujingensis has lower membranous labra, a generally continuous membranous zona with radiate spiny margins but, in some cases, dissected into single fimbria, and bearing sparsely distributed and locally forked stubby spines over the spore surface. Henrisporites qujingensis also has a four-layered wall. The innermost thin foot layer is covered by a loose layer of tiny parallel sporopollenin grains. A thick spongy layer is developed exterior to the second layer and comprises elongate, curved, and intersecting sporopollenin units forming a porous zone. The outermost layer consists of varied sculptural processes with contrasting densities between the proximal and distal surfaces. The morphological and ultrastructural characteristics suggest that these new megaspores belong to Isoetales. Our discovery represents the earliest global occurrence of Henrisporites, which has been documented exclusively from the Mesozoic in previous studies.
Place, publisher, year, edition, pages
Elsevier, 2023. Vol. 314, article id 104894
Keywords [en]
Henrisporites, Megaspore, Isoetales, Lycopsid, Permian, China
National Category
Other Earth and Related Environmental Sciences
Research subject
The changing Earth; Ecosystems and species history
Identifiers
URN: urn:nbn:se:nrm:diva-5444DOI: 10.1016/j.revpalbo.2023.104894OAI: oai:DiVA.org:nrm-5444DiVA, id: diva2:1817621
Funder
Swedish Research Council, 2018-04527Swedish Research Council, 2022-03920
Note
This study was jointly supportedby the Strategic Priority Research Program of Chinese Academy of Sciences (XDB26000000), the Second Tibetan Plateau Scientific Expedition and Research (2019QZKK0706), the Key Research Programof the Institute of Geology and Geophysics, Chinese Academy of Sciences (IGGCAS-201905), the China Scholarship Council (grant number 202207030014), and the Graduate Research Innovation Project of Yunnan University. S.M. is funded by grants from the Swedish Research Council (VR grantnumbers 2018-04527 and 2022-03920).
2023-12-012023-12-06Bibliographically approved