Phoenicopsis (Leptostrobales) and Pseudotorellia (Ginkgoales) from the Cretaceous of North Asia

Abstract

Two species of Torellia Heer with studied epidermal structure were described previously: Torellia rigida Heer (type species) from the Paleogene of Spitsbergen, and Torellia sp. from the Upper Cretaceous (Turonian–Coniacian) of New Siberia Island (the New Siberian Islands, Russia). The epidermal features of the Late Cretaceous leaves were revised and found to be identical to those of Phoenicopsis papulosa Samylina from the Arkagala River Basin (Magadan oblast', Russia). Thus, Torellia sp. is conspecific with P. papulose. Phoenicopsis is recognized in the Late Cretaceous flora of the New Siberian Islands for the first time. This is the northernmost occurrence of Phoenicopsis in Asia. Pseudotorellia leaves are recorded from the Lower Cretaceous of the Kenkeme River (Lena River Basin, Russia) for the first time. A new species, Pseudotorellia parvifolia, sp. nov., is described. It is notable by having very small hypostomatic leaves, smooth periclinal cell walls and absent of papillae on the subsidiary cells of the stomatal complexes. Besides this, Pseudotorellia leaves were found in the Upper Cretaceous of the Kiya River (Kemerovo oblast’, south of Western Siberia, Russia). This is the first occurrence of Pseudotorellia in the Upper Cretaceous of Western Siberia. We have studied the morphological and epidermal structures of these leaves and describe a new species, Pseudotorellia kiensis, sp. nov. The leaves of P. kiensis are peculiar in the straight to undulate anticlinal cell walls and longitudinal cuticular ridges of the periclinal cell walls of the both leaf surfaces. Analysis of a distribution of the Cretaceous Phoenicopsis and Pseudotorellia in North Asia revealed that remains of the Phoenicopsis leaves are unknown in the Cretaceous of Western Siberia and they are not as abundant in the Lower Cretaceous of the southern regions of North Asia as Pseudotorellia leaves, which dominated in some plant assemblages in the latter in this time. On the contrary, remains of the Pseudotorellia leaves are sporadic in the Lower Cretaceous deposits of the north of Eastern Siberia and northeastern Russia, while bundles of the Phoenicopsis leaves are numerous there. Both of these typically Mesozoic genera, Pseudotorellia and Phoenicopsis, persisted into the Lower Cenozoic.