Miocene Hymenaea flowers preserved in amber from Simojovel de Allende, Chiapas, Mexico

A diverse biota included in the amber of the early Miocene La Quinta Formation, Simojovel de Allende, Chiapas, Mexico, includes nicely preserved flowers of the legume genus Hymenaea (Caesalpinioideae: Detarieae), the same plant that produced the amber-forming resin. Our observations confirm the presence of two distinct species. Hymenaea mexicana Poinar and Brown is characterized by sub-equal clawed petals, and a verrucose and basally hirsute ovary, resembling the flower of extant Hymenaea verrucosa Gaertner (section Trachylobium), an African species. In contrast, the new species Hymenaea allendis Calvillo-Canadell, Cevallos-Ferriz & Rico-Arce is distinguished by its prominent nectariferous disc, and smooth glabrous ovary, thus resembling Hymenaea courbaril L. (section Hymenaea) with an American lineage of the genus. Different maturation stages of these flowers are preserved, with recognition of a development series that parallels that of extant relatives. Presence of these two species of Hymenaea, ca. 23 my ago in southern Mexico has interesting biogeographic implications for the development and history of neotropical floras during the mid-Cenozoic.