Paleobotany, relationships, and geographic history of Winteraceae

In combination with phylogenetic analyses of morphological and molecular data from modern plants, fossils allow improved reconstruction of the history of Winteraceae. Phylogenetic analyses link Winteraceae with Canellaceae, nested among Magnoliales, Laurales, and Piperales, implying that their lack of vessels is derived rather than primitive. The oldest records, from the Barremian and Aptian-Albian (Early Cretaceous) of Northern Gondwana (Gabon, Israel), are ulcerate tetrads (Walkeripollis) with an annulus underlain by thickened endexine but finer sculpture than modern Winteraceae, which most likely represent the stem-lineage leading to crown-group Winteraceae. Early Cretaceous Afropollis and Schrankipollis, which have also been compared with Winteraceae, are probably not related. The distribution of Walkeripollis implies that the winteraceous line originated in tropical, possibly dry, environments, like those of modern Canellaceae, rather than equable temperate and upland tropical habitats like those where Winteraceae occur today. Crown-group Winteraceae, first represented in the Santonian-Campanian (Late Cretaceous) by more coarsely reticulate tetrads in Australia and vesselless wood in Antarctica, and later by tetrads in South America and Africa, appear to he derived from a line that spread south into the temperate zone, consistent with ecological hypotheses that vessels were lost as an adaptation to cooler climates. Late Cretaceous paleogeography suggests that the crown-group could have dispersed to Australasia via either South America and Antarctica or Madagascar (where the family is represented by the basal genus Takhtajania) and India.