First data on the ultrastructure of the leaf cuticle of a Mesozoic conifer, Mirovia Reymanówna (Miroviaceae)

• The leaf cuticle ultrastructure of three Mirovia species is investigated by TEM.
• The thickness and features of the cuticle layers are described.
• Differences among the cuticle structures of Mirovia species are provided.
• Comparison of the Mirovia leaf cuticular structure with other conifers is done.

The ultrastructure of the leaf cuticle of Mesozoic conifers of the family Miroviaceae – Mirovia Reymanówna – was studied for the first time. The leaf cuticles of three Mirovia species from different localities and ages were investigated: Mirovia kazachstanica Nosova et Kiritchkova from the Lower Jurassic of the Mangyshlak Mountains (Kazakhstan), Mirovia macrophylla (Florin) Nosova from the Middle Jurassic of the Andøya Island (northern Norway) and Mirovia sibirica (Samylina) Bose et Manum from the Lower Cretaceous of the Lena River Basin (Russia). The data obtained from TEM analysis allow to give a detailed description of the cuticle structure of both the abaxial and adaxial surfaces. The cuticular membrane of Mirovia leaves is made up of the cuticle proper, composed of an outer polylamellate layer and an inner granular and homogeneous layer, and a cuticular fibrillate layer. The cuticle ultrastructures of the studied Mirovia species were compared with each other, and also with other fossil and extant conifers.