Smithsonian researcher finds new midge species, rare mosquito larvae from the Flathead

As millions pour every year into the Crown of the Continent — outfitted perhaps for any variety of Montanan adventure — one retired biochemist equipped with little more than a sharp putty-knife has been carving out tiny, 46 million-year-old flies from the shaley banks of the Flathead River.

Dale Greenwalt has been collecting these ancient insects from the Flathead’s Middle Fork as a resident research associate with the Smithsonian Institution during a few weeks each summer for the past 15 years.

Despite the glut of tourists, he and scant crew have been left to relative solitude, much like the tens of thousands of fossils — including elegantly preserved caddisflies, beetles, wasps and others — he so far collected from the river’s edges to laboriously catalog for the Smithsonian’s National Museum of Natural History in Washington, D.C.

Permitted by the Forest Service, he has now helped catalog a conservative 20,000 fossilized insects from the Middle Fork, starting from humble volunteer beginnings labeling boxes.

“The first project they gave me was to put tiny adhesive labels on 33,000 white specimen boxes,” Greenwalt said of his post-retirement venture. “That’s the kind of project most of the volunteers get, and I did that for a year.

“But then, I asked them for something a little more interesting,” he said.

And Greenwalt got it.

Best known for his ties to a rare fossilized mosquito found engorged with ancient blood, likely from a bird of the Middle Eocene those many millions of years ago, he and a research partner this year published several new midge species and one delicate mosquito larvae — an even rarer find.

“In fact, we’ve found seven or eight fossils of blood-engorged mosquitos now,” Greenwalt remarked of the Northwest Montana collection.

“It’s the only place in the world where these fossils exist,” he said. “It’s a very unique place.”

The ancient blood-swollen mosquito — the DNA long ago degraded beyond use — spurred headlines a decade ago.

The mosquito was actually found among specimen of Middle Fork shale stored in the basement of a Whitefish couple’s home, put there by their son and local researcher Kurt Constenius.

Greenwalt drew his post-retirement research influence from Constenius, whose family actually donated the shale specimen to the Smithsonian among nearly 1,000 pieces lovingly protected at the family home for nearly a quarter-century.

“Just by serendipity, when I retired, my wife and I decided to have a cabin built not very far away from the confluence of the North and Middle forks,” Greenwalt said of his initial findings of Constenius’ then-obscure work along the Middle Fork.

“Kurt Constenius and his family were very, very helpful,” he said. “They told me where to go. The fossils are difficult to find, but once you figure out where they are, there’s just an enumerable, infinite number of specimens available.”

Tourists laud the region for its rugged, glacially carved beauty.

Scientists laud its worldly unique ability to help record natural history through some of the rarest, most delicate of olden insects: tiny winged flies in their respective pupal and larval stages.

To date, Greenwalt and his research partners overall have published and named about 100 ancient insect species from within the bounds of Flathead National Forest.

Several sites, however, lie on the Glacier National Park-side of the Middle Fork, though Forest Service jurisdiction there extends to the high water mark, just high enough to recover fossils during late-summer low waters.

Greenwalt gets the specimen from a fossiliferous band of shale exposed along the river’s edges known as the Coal Creek Member of the Kishenehn Formation.

New discoveries and old, the shale and the creatures within it ultimately tell scientists the story of a tropical Montana, much like Florida is today, Greenwalt said.

“You want to kind of concentrate on the new species that are of particular scientific importance,” he said.

“The whole reason we’re collecting in the first place is to study the climate and the ecology that existed 46 million years ago, and of course, to study the evolution of the insects themselves,” Greenwalt said.

During Eocene times, spanning from roughly 56 million to 34 million years ago, odd- and even-toed ungulates like horses and deer, respectively, appear — as do the first recorded fully marine mammals, such as whales, dolphins and dugongs.

Evident in modern times as strips of exposed shale along the Middle Fork northward into Canada, the formation’s treasures are among the rarest in the world — procuring some of the most telling of ancient insect species: the tiny ones.

“Most of us, when we think of insects, we think of butterflies and grasshoppers and things like that — pretty big organisms,” Greenwalt said. “But 99% of all insects are really tiny, no-see-um kind of insects.

“Most of the fossils are only 2, 3 or 4 millimeters in length,” he added, noting that despite their size: “It gives us a very important window to the insects that existed back then that aren’t available other places.”

The window views a large, very shallow lake laden with algae where the insects perished.

Greenwalt said the lake, created by a fault, stretched perhaps some 100 miles into Canada during a wet season but likely became a collection of shallow potholes during a dry season.

“[These flies] had the bad luck to fly over or be blown over the surface of the lake,” Greenwalt said, also noting that the water itself did little to preserve the tiny creatures.

“But at that particular time, the surface of the water was covered by an algal bloom, a green slime kind of thing, and they got stuck in that,” Greenwalt said.

“The algae continued to grow and enveloped these insects, and helped preserve them,” he said. “That’s why they’re so beautifully preserved.”

Reporter John McLaughlin can be reached at 758-4439 or jmclaughlin@dailyinterlake.com