Reappraisal of the ill-defined Liassic pteridosperm Dichopteris using an ultrastructural approach

This review of the genus Dichopteris De Zigno is based on the original fossil specimens collected from the Lower Jurassic of the Grey Limestones of Veneto (Northern Italy). The cuticular diagnosis of the genus is emended and only Dichopteris visianica De Zigno is retained within the genus. In addition, transverse and longitudinal sections of cuticles examined using a transmission electron microscope (TEM) indicate close similarities between D. visianica and other pteridosperm cuticles, especially the occurrence of granules arranged in areas of different densities in the epidermal cells and stomatal apparatus. Moreover, the dichotomy and the impressive size of the frond of D. visianica imply a specific architecture with a typical arrangement of the pinnae and pinnules. They preclude an herbaceous habit for the plant. Finally, architectural, microstructural and ultrastructural observations are consistent with palaeoclimatic and palaeoenvironmental data, and most probably support an understorey habit for D. visianica.

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Source ISSN: 0024-4074
Author Thévenard, Frédéric, Barale, Georges, Guignard, Gaëtan, Daviero-Gomez, Véronique, Gomez, Bernard, Philippe, Marc, Labert, Nicolas
Maintainer CCSD
Last Updated May 10, 2026, 02:13 (UTC)
Created May 10, 2026, 02:13 (UTC)
Identifier hal-00085214
Language en
contributor PaleoEnvironnements et PaleobioSphere (PEPS) ; Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
creator Thévenard, Frédéric
date 2005-05-10T00:00:00
harvest_object_id 050c4b6e-2aac-416b-ae48-0dcc38bd9a62
harvest_source_id 3374d638-d20b-4672-ba96-a23232d55657
harvest_source_title test moissonnage SELUNE
metadata_modified 2025-03-25T00:00:00
set_spec type:ART