Fossil leaves of Cenomanian basal angiosperms from the Peruc-Korycany Formation, Czechia, central Europe

Abstract

Two leaf forms are described from the Cenomanian, Late Cretaceous of the Peruc-Korycany Formation in the Bohemian Cretaceous Basin in Central Europe. A new foliage genus and species Ascarinophyllum pecinovense Čepičková et J. Kvaček, gen. et sp. nov. is characterised by serrate margins with rounded chloranthoid teeth bearing a papilla. The leaf is hypostomatic, coriaceous, with resin bodies in the mesophyll. Its venation is festooned semicraspedodromous, with a robust midvein. On the abaxial cuticle, it shows laterocytic/laterocyclocytic, stephanocytic-bicyclic, amphibrachyparacytic, and less frequently brachyparacytic and holoparacytic stomata, showing sometimes T-shaped thickenings of the internal cuticle at the poles. The abaxial cuticle bears external striations; stomata are surrounded by stomatal rims. The leaf is compared to similar Early and Late Cretaceous angiosperm foliage, and to foliage of extant basal angiosperms. Cuticle analysis shows similarities in stomatal construction and external striations of the abaxial cuticle with fossil leaves of Mesodescolea plicata and extant Chloranthaceae.Todziaphyllum saportanum (Velen.) Čepičková et J.Kvaček comb.nov. is revised and its diagnosis is emended. T. saportanum leaf is characterised by serrate margins and semicraspedodromous venation. It is compared to morphologically similar Cretaceous angiosperm foliage, including Ascarinophyllum pecinovense. It is particularly similar to the recently defined fossil leaf Todziaphyllum elongatum, interpreted as having chloranthaceous affinity.