Ignatov, M.S., T.V. Voronkova, U.N. Spirina & S.V. Polevova. 2023. Arvildia, an Upper Permian moss and its possible relationships

Arctoa (2023) 32: 243–260

doi: 10.15298/arctoa.32.23

New collections of a Late Paleozoic moss Arvildia allowed us to circumscribe its morphology more precisely than it has been done earlier. Despite of the compression type of the material preservation, it was possible to embed the material from bulk maceration in epon-araldite resin and study it by a series of thin and ultrathin sections with light and transmission electron microscopy. The weakly differentiated leaf costa in the transverse section and thick-walled and strongly bulging leaf cells support possible relationships of Arvildia with Andreaeopsida rather than with Dicranidae, as it was supposed earlier. This study also shows that the cell damage differs in different parts of leaf and therefore such studies of compression highlight some biomechanical properties of moss leaves.