A New Fossil Genus of Altingiaceae Based on Unlobed Leaves from Eocene Subtropical Evergreen Broad-leaved Forest in Europe.

Premise of research. Abundant fossil records of Altingiaceae have been discovered from all Northern Hemisphere continents and suggest its widespread occurrence during the Paleogene, shedding light on its evolutionary history. However, records of unlobed Altingiaceae leaf fossils are rare and discovered only in East Asia to date. Methodology. Plant fossils were collected from the lignite opencast mine Profen-Süd in central Germany from late Eocene sediments of an alluvial coastal plain. From a total of 140 compressed leaves, cuticles were obtained from 52 specimens for studying epidermal characters. Leaf architecture and cuticle micromorphology were described and compared with fossil and extant species sharing similar characteristics. Pivotal results. The new material belongs to a rare and incompletely known fossil species from the same region and age. For taxonomic reasons, a new fossil genus— Zlatkophyllum gen. nov.—associated with Altingiaceae is established. Zlatkophyllum fischkandelii sp. nov. et comb. nov. is redescribed and reconsidered on the basis of the simple dentate, almost circular leaves with semicraspedodromous secondary vein framework; Ω-shaped anticlinal walls of epidermal cells; and brachyparacytic stomata. Conclusions. The new fossil genus is the first representative of Altingiaceae from the European Cenozoic with exclusively unlobed leaves, thus providing important implications for the evolutionary history of the family. In the fossil assemblage, Z. fischkandelii co-occurs with abundant Steinhauera subglobosa infructescences from the same family, and thus the new fossil taxon is hypothetically the previously unknown foliage of the S. subglobosa –producing fossil plant. [ABSTRACT FROM AUTHOR]