Taphonomic constraints on preservation of cuticles in compression fossils: fungi induced ultrastructural changes in cuticular membranes

Abstract

A comparative investigation has been made of the ultrastructure of the cuticular membrane recovered from healthy and fungal-infected leaves of Thinnfeldia indica Feistmantel, a fossil taxon to understand the nature of changes brought about in the cuticular membrane by the fungi. In general, the structural configuration of both the cuticular membranes is similar. In the infected leaf, precursors of cutin accretions are irregularly present at the sub-cuticular surface. These accretions are interpreted as possible results of the breakdown of the cutin due to the secretion of an enzyme by the fungi infecting the leaf. It thus seems that the fungi, besides edaphic factors, do play a role in the break-down of the cutin and thus constrain the preservation of the cuticular membranes.