Angiosperms in the Early Cretaceous of Northern Gondwana: A Track Record

This chapter reviews both systematics and ecology of the angiosperms from the Crato Formation, which are represented by members of all major angiosperm groups. These include the early-diverging ANITA grade (e.g., waterlilies, star anise), the magnoliids (e.g., magnolias, bay laurel), monocots and eudicots. The systematic composition of this assemblage is more comparable to younger assemblages from the northern mid-latitudes (Potomac zone II) dominated by eudicots than with their age equivalent (Potomac zone I) which are dominated by ANITA members and Chloranthaceae. This diachronism supports the idea of a poleward dispersal of angiosperms during the lower Cretaceous an idea already proposed by Axelrod in the 1950ss. Regarding their ecology, these angiosperms occupied the whole water and light supply, ranging from aquatic to drought-tolerant and from shade adapted to sun adapted. Nevertheless, these angiosperms were probably only herbaceous or shrubby, the conifers occupying the canopy. The systematic and ecological diversity of the angiosperms in the Crato flora shows that the radiation of angiosperms was already advanced in the tropics during the late Aptian.