Ancient amber offers evidence of oldest orchid fossil

May 4 (UPI) -- Researchers at Oregon State University have found evidence of the oldest orchid fossil on record.

Scientists have previously discovered orchid fossils dated between 20 and 30 million years old. The latest fossil is dated between 45 million and 55 million years old.

At first glance, the Baltic amber appears flower-free. The amber's most obvious victim is a fungus gnat. But when scientists looked more closely, they discovered a pollen sac on one of the gnat's legs.

"It wasn't until a few years ago that we even had evidence of ancient orchids because there wasn't anything preserved in the fossil record," George Poinar, Jr., a professor emeritus of entomology at Oregon State, said in a news release. "But now we're beginning to locate pollen evidence associated with insects trapped in amber, opening the door to some new discoveries."

The new evidence suggests orchids were already thriving during the Eocene Epoch and likely feature lineages with their beginnings in the Cretaceous period.

With at least 28,000 species, the flower family Orchidaceae is one of the most diverse groups of flora or fauna on Earth. By comparison, there are 9,956 bird species.

The large flower family has evolved a diverse array of tricks to lure in pollinating insects. Many orchids put out a smell offering the false promise of food.

"We probably shouldn't say this about a plant, but orchids are very smart," Poinar said. "They've developed ways to attract little flies and most of the rewards they offer are based on deception."

Researchers detailed the discovery of the record-setting orchid fossil in Botanical Journal of the Linnean Society.