A recent discovery of plant fossils in New Brunswick, Canada, unveils previously unknown appearances of ancient trees featuring characteristics never observed before. These fossils, presenting an unexpected three-dimensional crown structure, offer a unique glimpse into the morphology of trees dating back 350 million years and are scientifically named
Sanfordiacaulis densifolia.
Reconstruction of Sanfordia caulis densifolia
(A) Scale reconstruction of S. densifolia composed of a monopodial trunk surrounded by compound leaves in an estimated phyllotaxy of 1/13; base of the trunk unknown.
(B) Inset showing the initiation of lateral branches at multiple levels compared to mud for comparison. MNB 22403/1. Coin for scale.
(C) Changes in cross-section geometries from proximal to distal of the petiole/rachis. Numbers correspond to the position of the leaves in (A). According to Robert Gastaldo from Colby College in Waterville, Maine, "the way this tree produced huge leaves around its slender trunk, in a large number over a short length of the trunk, is astounding." This discovery holds particular importance since most trees are typically preserved only in the form of trunks, without any indication of their crown or overall shape.
According to the press release, the exceptional preservation of these fossils is due to their burial in an ancient fault lake caused by an earthquake. The specimen of
Sanfordiacaulis presents an appearance similar to that of ferns or palms, a surprising find since palms only appear much later in the known records. However, unlike ferns and palms which have few leaves at the top, the fossilized tree presents more than 250 leaves along its trunk, which measures about 7.4 feet (2.25 meters).
"Unlike others,
Sanfordiacaulis retains over 250 leaves around its trunk, each partially preserved leaf extending over 5.7 feet (1.75 meters)," explains Gastaldo. "We estimate that each leaf grew by at least 3.2 feet before ending. This means that the 'bottlebrush' had a dense crown of leaves extending over at least 18 feet around a non-woody trunk of only 6.3 inches in diameter. Surprising, to say the least."
The researchers propose that
Sanfordiacaulis represents the first documented evidence of smaller trees thriving under a taller forest canopy. Moreover, it offers remarkable proof of the diversity of plant life at the beginning of the Carboniferous period. Robert Gastaldo concludes in the press release: "The fossil we report on is unique and a strange growth form in the history of life. It's one of the evolutionary experiments at a time when forest plants were undergoing biodiversification, and it's a form that seems to have been short-lived."
Author of the article: Cédric DEPOND