Fossil evidence for the evolution of biotic pollination

Abstract

Earliest Cretaceous flowers were small apetalous magnoliids with few parts. They co-occurred with a greater variety of anthophilous insects than has previously been supposed, and the idea that Coleoptera were the principal early insect pollinators needs review. By the mid-Cretaceous rosid flowers are known with well-developed corollas and the Rosidae are diverse by the late Cretaceous. The more derived asterid floral types are not firmly established until the Tertiary. Nectaries are present in many of the late Cretaceous rosids and may signal the beginning of the most significant revolutionary interaction between Hymenoptera and angiosperms. Advanced floral types in Maastrichtian and early Tertiary deposits are consistent with the appearance of meliponine Apideae (stingless honeybees) in the later Cretaceous. -from Authors