A bee specimen about 40 million years older than any known bee fossil was found in a sample of amber. ((Bryan Danforth/Cornell University))

An Oregon State University scientist has discovered a bee dating to 100 million years ago trapped in amber, making it possibly the oldest bee ever found.

The ancient bee, about 40 million years older than any known bee fossil, may help explain the rapid expansion and diversity of flowering plants during that time.

George Poinar, a zoology professor at Oregon State University, found the bee in amber from a mine in northern Myanmar, formerly known as Burma.

Amber is a semi-precious stone that begins as sap flowing from certain trees. Sometimes insects, plants, or small animals become trapped in the sap and are preserved in near-perfect condition.

Poinar says the ancient bee shares some of the features of wasps, such as narrow hind legs and branched hairs all over its body, as well as other characteristics of pollen-spreading bees.This species, named Melittosphex burmensis, is long extinct.

Poinar's ancient male bee is not a honeybee and not related to any modern bee family.

This fossil may help us understand when wasps, which were mostly just carnivores, turned into bees that could pollinate plants and serve a completely different biological function, according to Poinar.

The ancient bee may be an evolutionary dead end and may not have evolved into modern bees, said scientists.

An article on the discovery, co-authored by Bryan Danforth of Cornell University appears inthe latestedition of the journal Science.