First Orchid Fossil Puts Showy Blooms At Some 80 Million Years Old

[Bianca]

             

              Amber-preserved stingless bee carrying pollinia
              of Meliorchis caribea, the first unambiguous
              fossil orchid known to science.

              This discovery enabled researchers to calculate
              the time of origin of the orchid family.

              (Credit: Santiago Ramírez)








                                First Orchid Fossil Puts Showy Blooms At Some 80 Million Years Old






ScienceDaily
(Aug. 30, 2007) —

Biologists at Harvard University have identified the ancient fossilized remains of a pollen-bearing bee as the
first hint of orchids in the fossil record, a find they say suggests orchids are old enough to have co-existed
with dinosaurs.

Their analysis, published recently in the journal Nature, indicates orchids arose some 76 to 84 million years ago, much longer ago than many scientists had estimated. The extinct bee they studied, preserved in amber with a mass of orchid pollen on its back, represents some of the only direct evidence of pollination in the fossil record.

"Since the time of Darwin, evolutionary biologists have been fascinated with orchids' spectacular adaptations for insect pollination," says lead author Santiago R. Ramírez, a researcher in Harvard's Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology. "But while orchids are the largest and most diverse plant family on Earth, they have been absent from the fossil record."

The fossil record lacks evidence of orchids, Ramírez says, because they bloom infrequently and are concentrated
in tropical areas where heat and humidity prevent fossilization. Their pollen is dispersed only by animals, not wind, and disintegrates upon contact with the acid used to extract pollen from rocks.

Orchids' ambiguous fossil record has fed a longstanding debate over their age, with various scientists pegging the family at anywhere from 26 to 112 million years old. Those arguing for a younger age have often pointed to the lack of a meaningful fossil record as evidence of the family's youth, along with the highly specialized flowers' need for a well-developed array of existing pollinators to survive. Proponents of an older age for orchids had cited their ubiquity around the world, their close evolutionary kinship with the ancient asparagus family, and their bewildering diversity: Some 20,000 to 30,000 species strong, the showy plants comprise some 8 percent of all flowering species worldwide.

[Bianca]

                                                   First Orchid Fossil Found in Amber 






National Geographic
August 29, 2007

—For this ancient bee, carrying a flower into the afterlife allowed it to deliver a rare gift to today's biologists.

The extinct species of stingless bee was found encased in amber with a well-preserved part of an ancient orchid attached to its back. The amber, dug up in a mine in the Dominican Republic, is 10 million to 15 million years old.

The pollen-bearing package represents the first known fossil of an orchid, researchers say.

Orchids are the most diverse flowering plants on Earth, with more than 20,000 known species (see photos of new orchids found in New Guinea in 2006). But until now the flowers have been absent from the fossil record.

In a paper describing the find in tomorrow's issue of the journal Nature, Santiago R. Ramírez of Harvard University and colleagues note that the fossil flower, called Meliorchis caribea, belongs to a living group of orchids called Goodyerinae.

In addition to shedding new light on the orchid family tree, the find provides "an unprecedented direct fossil observation of a plant-pollinator interaction," the team writes.

For example, when bees visit living members of Goodyerinae, the pollen parts become stuck to their mouths as they take nectar from the lip of the flower. But the fossil pollen was found stuck to the ancient bee's back.

"This indicates that the flower of M. caribea was gullet-shaped," the researchers write. "The anterior part of the bee would have had to enter the flower completely."



—Victoria Jaggard