Angiosperm leaves associated with Sinocarpus infructescences from the Yixian Formation (mid-Early Cretaceous) of NE China

Abstract

Typical angiosperm dicot leaves are discovered closely associated with reproductive organs of Sinocarpus decussatus from the Yixian Formation, NE China. Leaves are of first rank, small, with fine texture, and with distinct petiole and lamina. Venation pattern is craspedodromous, of at least three discrete orders of veins irregularly arranged. Leaf margin is serrate, with glandular teeth of chloranthoid type. The new Sinocarpus material is better preserved and more complete than the type specimen. It yields support for previous interpretations of reproductive characters and shows that the inflorescences were compound, perhaps combining alternate and opposite phyllotaxis, and that seeds were arranged in two rows, each row with about ten seeds. While these new reproductive characters do not provide further resolution to the systematic assignment of Sinocarpus, the associated leaves, believed to be from the same plant, support previous interpretation of Sinocarpus as a basal eudicot, and particularly close to Ranunculales.