Rare Fossil Shows Trees Looked Very Different 350 Million Years Ago

Scientists in Canada have discovered a 350-million-year-old tree fossil that could shed light on a little-known era of prehistory. The plant sports an odd, top-heavy shape that has been compared to both a Dr. Seuss doodle and an upside-down toilet brush.

Dating to the late Paleozoic Era, the tree was alive during a mysterious period paleontologists refer to as Romer’s gap: a relatively short span of time between 345 million and 360 million years ago, after fish began to take to land.

Not much is known about the trajectory of life throughout those 15 million years, but the new discovery suggests it was a particularly experimental time for the evolution of large forest plants, the scientists write in their study, published last week in the journal Current Biology.

Many trees and plants from that era exhibited structures and materials that did not last into the modern age—this unusual tree included.

“This is a totally new and different kind of plant,” Patricia Gensel, a biologist at the University of North Carolina at Chapel Hill and an author of the study, tells the New York Times’ Robin Catalano. “We typically get bits and pieces of plants, or mineralized tree trunks, from Romer’s gap. We don’t have many whole plants we can reconstruct. This one we can.”

The newly identified species, called Sanfordiacaulis densifolia, was found near the bottom of an active rock quarry in Valley Waters, New Brunswick, in Canada’s Stonehammer UNESCO Global Geopark. Millions of years ago, the now-forested area was a tropical wetland ecosystem where a deep lake extended across fault lines. Earthquakes and mudslides often changed the volatile landscape, and vegetation sometimes became swept up in the tumbling sediment and got preserved, buried, at the bottom of the water.

Fossilized tree fragments had previously been found in the area, though no specimen was as intact as the new find. The fossil’s trunk, branches and partially preserved leaves were found three-dimensionally pressed into stone, joining just five or six other Paleozoic trees currently in the fossil record that have their leaves and branches intact, reports CNN’s Ayurella Horn-Muller. Because they are so delicate, complete tree or plant fossils are rarer to find than dinosaur skeletons.

The team used spore dating to determine the fossil’s age and created digital renderings of the tree’s dimensions and makeup. Its trunk was six inches in diameter, stretched nearly ten feet tall and was made of fern-like vascular material instead of woody bark. Congregated around the tree’s top, more than 250 lengthy, compound leaves extended from 2.5-foot branches. All told, the narrow trunk supported a wide canopy with a diameter of roughly 18 feet.

This incredibly top-heavy arrangement, the team hypothesizes, is not only cartoonish but represents the period’s incredible evolutionary experiments. Most likely, this structure allowed for a maximal amount of sunlight capture within the forest’s sub-canopy zone, a space between the tallest and shortest trees and plants. To keep itself upright, S. densifolia might have intertwined its branches with those of other trees.

“It is one of evolution’s experiments during a time when forest plants underwent biodiversification, and it is a form that seems to be short lived,” Robert Gastaldo, a paleontologist at Colby College who led the study, tells Forbes’ Leslie Katz.

The discovery and its odd shape demonstrate that even hundreds of millions of years ago, life was evolving to fill specific niches.

“The new fossils are a milestone in our understanding of how early forest structure evolved, eventually leading to the complex rainforest architectures that support most of Earth’s living biodiversity,” Peter Wilf, a geoscientist and paleobotanist at Pennsylvania State University, who was not involved with the study, tells CNN.

Christian Thorsberg | READ MORE

Christian Thorsberg is an environmental writer and photographer from Chicago. His work, which often centers on freshwater issues, climate change and subsistence, has appeared in Circle of Blue, Sierra magazine, Discover magazine and Alaska Sporting Journal.