Endressianthus, a new Normapolles-producing plant genus of Fagalean affinity from the Late Cretaceous of Portugal

New Normapolles reproductive structures are described from two Late Cretaceous localities, Mira and Esgueira ( Olho de Agua), in the Beira Litoral region of western Portugal. They are assigned to a new genus, Endressianthus, containing two new species, Endressianthus miraensis and Endressianthus foveocarpus. The new genus is based on several small inflorescence fragments with cymose branching and dichasial inflorescence subunits bearing either pistillate or staminate flowers, as well as on numerous isolated stamens and fruits. The pistillate flowers have an inferior ovary and minute, acicular tepals. The gynoecium is bicarpellate and syncarpous. In the fruiting stage, the stigmatic area on top of the ovary is seen as an elongate slit that is covered by stiff simple trichomes. Fruits are nuts with one or two locules and one or two seeds. The staminate flowers consist of four stamens with short filaments and elongate tetrasporangiate anthers and apparently a whorl of small, thornlike tepals. Typically, only one to three stamens develop into maturity while the other stamens in the flower abort. Pollen grains in situ show close similarity to dispersed pollen of the genus Interporopollenites. They are oblate with triangular equatorial contour, rounded protruding germinals, three endopores and six exopores, and a distinct arcus that interconnects the germinals. Organization of the inflorescence and flowers as well as the structure of the pollen indicates that this new Normapolles flower is of Fagalean affinity. The newly described taxon is apparently particularly close to members of the Betulaceae and may represent an extinct lineage at the root of the Betulaceae.