Caught in amber
Since Darwin's time, biologists have been fascinated by the intimate relationship between orchids and their pollinators. The antiquity of this relationship is demonstrated by the remarkable fossil preserved in 15–20-million-year-old amber from the Dominican Republic, a worker stingless bee carries an orchid pollinarium. The pollinarium is the male reproductive structure, transferred as a single unit during pollination, complete with a mass of pollen grains. The find, surprisingly, is the first definitive fossil from the Orchidaceae family. The pollinarium's morphology locates the plant in the subtribe Goodyerinae. By combining this information with dates from related fossil plants, a new calibration of the molecular phylogeny of the Orchidaceae has been obtained. The analysis rejects the common assumption of a recent (Tertiary) origin for orchids, and suggests, instead, that they originated during the Late Cretaceous, 80 million years ago.
These results have been reported by Santiago R. Ramírez of the Harvard University's Museum of Comparative Zoology, 26 Oxford St. Cambridge, MA 02138 USA.Letter: Dating the origin of the Orchidaceae from a fossil orchid with its pollinator
Santiago R. Ramírez, Barbara Gravendeel, Rodrigo B. Singer, Charles R. Marshall & Naomi E. Pierce
doi:10.1038/Nature Volume 448 Number 7157 969-1080
First paragraph
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