Pseudotorellia Florin from the Upper Jurassic–Lower Cretaceous of the Bureya Basin, Russian Far East

Abstract

Abstract The leaves of the genus Pseudotorellia from the Upper Jurassic–Lower Cretaceous of the Bureya Basin (Russian Far East) have been revised. The similarity of Pseudotorellia angustifolia Doludenko and P. longifolia Doludenko in the morphology and epidermal characters suggests that P. longifolia is a synonym of P. angustifolia. Leaves of this genus from the Bureya Basin previously assigned to P. ensiformis (Heer) Doludenko according to both morphological and epidermal characters are described as a new species P. doludenkoae sp. nov., since the type specimens of P.ensiformis from the Irkutsk Basin do not have preserved cuticles and their leaf epidermal characters are unknown. The epidermal characters of leaves described previously as Pseudotorellia pulchella and P. crassifolia have been studied for the first time. Since these species have similar morphological and epidermal characters, they are described as P. crassifolia, and its emended diagnosis is provided. The well-defined epidermal characters of Pseudotorellia allow us to reliably assign even cuticle fragments and dispersed cuticles to a particular species. This indicates a large stratigraphic potential of the Pseudotorellia species for the intrabasin and interregional stratigraphy of continental deposits, especially when studying the core material and coals, where the preservation of plant remains usually does not allow describing their morphology. The revision of all known occurrences of Pseudotorellia angustifolia makes it possible to discuss the place and time of the first appearance of this species and its subsequent distribution in space and time. Apparently, this species appeared in the Early Jurassic of Eastern Siberia (Kansk Basin). In the Middle Jurassic, its range expanded both to the northwest (Tomsk oblast and Yamal-Nenets Autonomous Okrug), where this species was preserved until the Late Jurassic, and to the east (Irkutsk oblast, Khabarovsk krai (Bureya Basin)), where it survived until the Early Cretaceous.