Integrating Early Cretaceous fossils into the phylogeny of living angiosperms: Magnoliidae and eudicots

Abstract

Abstract Over the past 25 years, discoveries of Early Cretaceous fossil flowers, often associated with pollen and sometimes with vegetative parts, have revolutionized our understanding of the morphology and diversity of early angiosperms. However, few of these fossils have been integrated into the increasingly robust phylogeny of living angiosperms based primarily on molecular data. To remedy this situation, we have used a morphological dataset for living basal angiosperms (including basal eudicots and monocots) to assess the most parsimonious positions of early angiosperm fossils on cladograms of Recent plants, using constraint trees that represent the current range of hypotheses on higher‐level relationships, and concentrating on Magnoliidae (the clade including Magnoliales, Laurales, Canellales, and Piperales) and eudicots. In magnoliids, our results confirm proposed relationships ofArchaeanthus(latest Albian?) to Magnoliaceae,Endressinia(late Aptian) to Magnoliales (the clade comprisingDegeneria,Galbulimima,Eupomatia, and Annonaceae), andWalkeripollispollen tetrads (late Barremian?) to Winteraceae, but they indicate thatMauldinia(early Cenomanian) was sister to both Lauraceae and Hernandiaceae rather than to Lauraceae alone. Among middle Albian to early Cenomanian eudicots, we confirm relationships ofNelumbitestoNelumbo, platanoid inflorescences andSapindopsisto Platanaceae, andSpanomerato Buxaceae. With the possible exception ofArchaeanthus, these fossils are apparently not crown group members of living families but rather stem relatives of one or more families.