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Exceptionally well-preserved fossils of bushy trees have been found in southeastern Canada. These strange plants are unlike anything scientists have ever found. They have already been called great examples of how evolution experiments with form.

An earthquake 350 million years ago toppled these trees and buried them in a mud bath; It left almost perfect traces of its stems and leaves in the sediments at the bottom of the ancient lake. Geologists discovered the first petrified tree during excavation at a quarry in New Brunswick in 2017, and later unearthed four more nearly identical trees.

We were surprised. Finding a tree-sized fossil plant with preserved leaves attached to a crown-shaped trunk is an anomaly.
says the study’s lead author, Robert Gastaldo, professor emeritus of geology at Colby College in Maine.

Only the trunks of ancient trees are usually preserved in fossils. But the new find shows a dense canopy of more than 250 leaves clustered around the top 75 centimeters of a spindle-shaped, unbranched tree trunk about 2.7 meters high. The leaves grew up to 10 feet long and spread from the stem in “tightly compressed spirals,” according to the study published Feb. 2.

Tree leaves are very rarely preserved as fossils, but this specimen has survived / Photo: Matthew Stimson

Trees called Sanfordiacaulis likely evolved in this spiral style to maximize the amount of sunlight the leaves captured for photosynthesis, the researchers wrote. Their shorter stature also indicates that these plants are the earliest example of smaller trees growing under the canopy of taller trees.

According to Gastaldo, reconstructing these plants “disrupts our understanding of how trees are organized and grow.” But this is not surprising, because the fossils found lived hundreds of millions of years ago, at a time when literally everything was different. Although their architectures are markedly different, a small number of trees share subtle similarities with a variety of plant species found in the modern tropics, including ferns, gymnosperms (gymnosperms), and flowering plants. But these modern plants have a smaller number of leaves in their crowns – from 15 to 20 in tree ferns and palms.

According to Gastaldo, Sanfordiacaulis may have stood out among the vegetation of the Carboniferous period (359-299 million years ago), just as poplars and baobabs stand out among other trees on the planet today.

Olivia King, who was involved in the discovery of new fossils, sits next to one of the Sanfordiacaulis specimens / Photo: Matthew Stimson

As you know, plants diversified significantly during the Devonian period (419 to 359 million years ago) and the Carboniferous period. According to Gastaldo, these strange fossils may be an example of an evolution experiment that failed at that time. “The evolution of the plant world has gone through many different experimental forms that have been successful for a million years or more but have not stood the test of time.”said the scientist.