Liriodendroid seeds from the Late Cretaceous of Kazakhstan and North Carolina, USA

Three new species (Liriodendroidea alata, L, latirapha, and L. carolinensis) are established based on well-preserved seeds from the Late Cretaceous of Kazakhstan and eastern North America. The Kazakhstan material is Cenomanian-Turonian in age and represents the oldest well-supported occurrence of the Magnoliaceae in the Cretaceous. The North American material is slightly younger (Campanian). The seeds described here share several critical characters with seeds of extant and Tertiary species of Liriodendron (Magnoliaceae) including anatropous organization and endotestal seed coat structure with a distinct endotesta of palisade-shaped sclerenchyma cells containing fibrous lignifications and cubic crystals. Other characters shared with Liriodendron and other Magnoliaceae include the characteristic fingerprint-like pattern on the surface of the endotesta and formed from the cells of the mesotesta, the presence of a distinct heteropyle, and a thin, crushed tegmen. The Cretaceous seeds from Kazakhstan and North Carolina differ, however, from those of modern Liriodendron in their smaller size and in having a distinct wing indicating that seeds were dispersed separately by wind in contrast to seeds of Liriodendron that are dispersed within the indehiscent and winged fruitlets. The occurrence of several adhering seeds documents that the fruitlets in at least two species of Liriodendroidea contained more than two seeds, a feature which indicates a shift in reproductive strategy in the tribe Liriodendreae from the Cretaceous to the present.