An Oregon scientist and a Kentucky nurse have found the oldest known mushroom, entombed in a 100-million-year-old piece of amber from Burma. A closer examination of the nine-hundredths-inch-long mushroom cap revealed that it had been infected by an ancient parasite, which a second parasite was feeding on.
"I was amazed enough with the mushroom," said George Poinar, a retired entomology professor in Corvallis. "But then seeing the parasites was astonishing. No one has ever seen this three-tier association before."
Poinar, formerly of the University of California at Berkeley, said the mushroom was spotted about a year ago by Ron Buckley, a registered nurse and amber-fossil collector and photographer from Florence, Ky. Buckley sent the amber specimen to Poinar, who confirmed the discovery and found the two parasites.
"This shows how far back mushrooms -- and the parasites that infect them -- go," Poinar said. "They're similar to pinwheel mushrooms that grow on the bark of modern trees. They dotted the trees 100 million years ago, so they probably were tasty treats for the dinosaurs to nibble on."
Poinar, a courtesy zoology professor at Oregon State University, and Buckley reported their discovery in the journal Mycological Research. Amber is fossilized tree resin, a sticky substance that oozes from certain pine and legume trees. The resin has chemical properties that act as a natural embalming agent for the ancient creatures that become trapped in it.
"I knew right away what it was when I looked at it under the microscope," said Buckley, who has been collecting amber fossils for the past eight years. "I sent the specimen to George right away because of his expertise, and he found those parasites. This is an incredible find."
Poinar received widespread attention last year for his discovery of the oldest bee -- a 100-million-year-old specimen from the same area in northern Burma where the amber is mined. Four kinds of flowers also were embedded in the amber. The mushroom is about 20 million years older than previously found mushroom fossils. The amber apparently broke off the mushroom's stem, sealing it along with small pieces of the tree's bark and other debris.
Joseph Spatafora, a fungi specialist and a professor of botany and plant pathology at OSU, said the amber discovery is significant because mushroom fossils are rare. Few ancient mushrooms -- the fruiting bodies of fungi -- survive because they lack bones or shells that help preserve other organisms.
"So the amber specimen can give us a lot of insight to what fungal diversity was at this time in the past," Spatafora said, and gives scientists an idea about fungi's role in forest ecosystems. Richard L. Hill: 503-221-8238;
http://www.oregonlive.com/news/oregonian/index.ssf?/base/news/118101211649610.xml&coll=7 RICHARD L. HILL