Female reproductive structures of Umaltolepis Krassilov and associated leaves of Pseudotorellia Florin from the Middle Jurassic of East Siberia, Russia

Abstract

Female organs of Umaltolepis are recorded from the Middle Jurassic of East Siberia for the first time. A new species, Umaltolepis irkutensis, sp. nov., is described from the Aalenian–Bajocian Prisayan Formation of the Irkutsk Coal Basin. It is notable for having papillae on some subsidiary cells of the stomatal complexes, on some ordinary epidermal cells of the middle part of the lobes and on the cells near the lobe bases. Cupules of U. irkutensis were found in association with Pseudotorellia leaves described here as a new species Pseudotorellia irkutensis, sp. nov. Leaves of this species are long and narrow, they are peculiar in possessing predominantly short epidermal cells on the adaxial side of the leaf, ordinary epidermal cells with smooth periclinal walls, stomata arranged in not always clear bands on the abaxial side of the leaf, and the presence of papillae on the subsidiary cells of the stomata. The co-occurrence of U. irkutensis with leaves of P. irkutensis in the same samples from the Irkutsk Basin, as well as their similar epidermal pattern, suggests that these remains most likely belonged to the same Umaltolepis–Pseudotorellia plant. The morphology and epidermal features of Umaltolepis female organs are discussed.