Orchidaceae - Evolution

Evolution

A study in the scientific journal Nature has hypothesized that the origin of orchids goes back much longer than originally expected. An extinct species of stingless bee, Proplebeia dominicana, was found trapped in Miocene amber from about 15-20 million years ago. The bee was carrying pollen of a previously unknown orchid taxon, Meliorchis caribea, on its wings. This find is the first evidence of fossilised orchids to date. The extinct orchid M. caribea has been placed within the extant tribe Cranichideae, subtribe Goodyerinae (subfamily Orchidoideae).

This indicates orchids may have arisen 76 to 84 million years ago during the Late Cretaceous. In other words, they may have coexisted with dinosaurs. It also shows insects were active pollinators of orchids then. According to Chase et al. (2001), the overall biogeography and phylogenetic patterns of Orchidaceae show they are even older and may go back roughly 100 million years.

Using the molecular clock method, it was possible to determine the age of the major branches of the orchid family. This also confirmed that the subfamily Vanilloideae is a branch at the basal dichotomy of the monandrous orchids, and must have evolved very early in the evolution of the family. Since this genus occurs worldwide in tropical and subtropical regions, from tropical America to tropical Asia, New Guinea and West Africa, and the continents began to split about 100 million years ago, significant biotic exchange must have occurred after this split (since the age of Vanilla is estimated at 60 to 70 million years).