They found a complete fossil of a strange tree dating back to 350 million years ago

“The way this tree produced very long leaves around its long trunk, and the large number of leaves on such a short trunk, is surprising,” explains Robert Gastaldo of Colby College in Waterville, Maine, the first signatory on the article. .

Like a palm tree…but no

In general, the shape of this very ancient tree, before the age of dinosaurs, is reminiscent of a fern or a palm tree, although palm trees did not appear until 300 million years later and usually have leaves and fern leaves very few and all gathered at the top.

“On the other hand – Gastaldo continues – the Sanfordiacolis plant maintains more than 250 leaves around its trunk, each one extending 1.75 metres. We estimate that each leaf grew by at least one meter before completing its development. “Which means this bottlebrush had a dense canopy of leaves extending at least 5.5 meters around a non-woody trunk that was only 16 cm in diameter, to say the least.”

This discovery provides valuable information about the evolution of plants and trees, i.e. plants that grew at least 4.5 metres. It also reminds us that throughout Earth's long history there have been trees that are unlike any we've ever seen before, and that sometimes seem to have emerged from the imagination.

“We all have a mental concept of what a tree looks like,” says Gastaldo, “depending on where we live on the planet, and we have a clear vision of what is familiar to us. But the fossil we report in our article is unique, and has a growth pattern that is rare in the history of life.” “It is an experiment in evolution during a period in which forest plants were diversifying, a form that appears to have been short-lived.”

Buried by an earthquake

Fossils of these exceptional trees, which lived on the edges of a lake, were able to preserve them completely after they were suddenly buried during an earthquake that occurred about 350 million years ago. The first of these fossilized trees was discovered seven years ago in a quarry, but it was only a partial sample. It took several years until four more specimens of the same plant were found, very close to each other.

One of these samples revealed how the leaves radiate from the tree's crown, which is “quite unique” according to the researchers. In fact, it is one of the few fossils in a record spanning more than 400 million years in which only a single stem has been preserved around which some crown leaves can still be seen.

The researcher says: “Any fossil tree with an intact crown is considered rare in the history of life.” The presence of crown leaves attached to its trunk allows us to ask what kind of plant it is, how this plant is organized and whether it has some form that continues to the present or whether, on the contrary, it remains outside the “natural” “concept” of a tree. . “All of these questions, and more, led to this multi-year effort.”

Failed experiment

In their study, the researchers explained that the tree may have relied on its strange growth pattern to increase the amount of light it could capture and thus reduce its competition with other nearby plants. Gastaldo and his colleagues suggest that the tree represents the oldest evidence of young trees growing under a higher forest canopy. Which means that early Carboniferous plant life was more complex than expected, and that Sanfordiacolis lived at a time when plants were “experimenting” with a variety of possible shapes and structures.

«The history of life on Earth – concludes Gastaldo – consists of plants and animals that do not resemble any of those living today. Evolutionary mechanisms operating in the deep past gave rise to organisms that lived successfully for long periods of time, but whose forms, growth structures, and life histories followed different paths and strategies. “Rare and unusual fossils, like the New Brunswick tree, are just one example of what once colonized our planet, but it was a failed experiment.”