Open AccessReappraisal of the ill‐defined Liassic pteridosperm Dichopteris using an ultrastructural approach
Author(s) -
THÉVENARD FRÉDÉRIC,
BARALE GEORGES,
GUIGNARD GAËTAN,
DAVIEROGOMEZ VÉRONIQUE,
GOMEZ BERNARD,
PHILIPPE MARC,
LABERT NICOLAS
Publication year - 2005
Publication title -
botanical journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.872
H-Index - 68
eISSN - 1095-8339
pISSN - 0024-4074
DOI - 10.1111/j.1095-8339.2005.00439.x
Subject(s) - biology , frond , ultrastructure , genus , habit , herbaceous plant , paleontology , botany , psychology , psychotherapist
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 . © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 313–332.