A first record of possible caytonialean pteridosperms from the Upper Bajocian (Middle Jurassic) of Northern Caucasus, Russia

This paper deals with the discovery of possible caytonialean pteridosperm macrofossils from the Middle Jurassic of the Kuban River Basin. Numerous remains of these plants have been found in the Upper Bajocian of Karachay-Cherkessian Republic of Russia, in association with various age-diagnostic ammonites (Spiroceras, Baculatoceras, Strenoceras, etc.). The level bearing these finds dates back to the Niortense Zone (Baculatum Subzone, bispinatum faunal horizon). The leaves show a characteristic reticulate venation. Putative female and male reproductive organs from this locality are also described. Finally, this paper discusses the role of caytonialean pteridosperms in the evolution of the Plant Kingdom and in the appearance of flowering plants. Some considerations on the regional palaeogeography are given as well.