A recent discovery shakes up our knowledge of plant evolution. Fossils dating back 47 million years, unearthed in Utah, have revealed the existence of a plant like no other, belonging to a family that is now extinct. This species, named Othniophyton elongatum, is redrawing the boundaries of paleontological botany.
A fossil that is out of the ordinary
The first traces of Othniophyton elongatum were discovered in 1969 in the Green River Formation, an exceptional reserve of fossils dating from the Eocene. This period, stretching from 56 to 33.9 million years ago, saw the emergence of many species of flowering plants. Scientists at the time classified this fossil in the Araliaceae family, known to include ginseng, angelica and ivy. However, recent research has demonstrated that this classification is incorrect.
Why a classification error?
The initial fossils consisted mainly of isolated leaves. The latter resembled compound leaves, like those of certain modern plants of the genus Oreopanax. However, the discovery of new specimens including leaves, fruits and complete branches allowed for more in-depth analysis.
Steven Manchester, paleobotanist at the Florida Museum of Natural History, explains: “These new, more complete fossils show that the leaves are not compound and that the morphology of the fruits does not match any known plant. »
A plant with no modern equivalent
Microscopic analysis of the fossils has revealed fascinating details. The fruits of Othniophyton elongatum present a rare feature: their stamens, the male parts of the flower, remain attached to the ripe fruit, a characteristic absent in modern plants.
Technological tools to the rescue
Using a state-of-the-art microscopy station, researchers were able to examine the seeds, stamens and pericarp of the fruits with unparalleled precision. This analysis confirmed that Othniophyton elongatum does not correspond to any existing plant order, although it has similarities with the order Caryophyllales. However, the differences were too great to include it in this order.
Implications for science
An extinct plant family
The researchers conclude that Othniophyton elongatum belongs to a completely extinct family, which calls into question some assumptions about the evolution of flowering plants. Until now, it was assumed that the majority of Eocene fossil plants were related to modern species. This discovery shows that entire lineages could have disappeared without leaving descendants.
Understanding adaptation and extinction
Studying plants like Othniophyton elongatum offers valuable insight into adaptation strategies and causes of extinction. For example, the presence of persistent stamens could indicate a unique method of reproduction, perhaps ineffective in changing environments.
A warning for researchers
This discovery highlights the dangers of biased assumptions. According to Steven Manchester: “It is tempting to associate a fossil with a modern family to simplify things, but this approach can take us away from the scientific truth. »
In conclusion: a mystery to be solved
Othniophyton elongatum remains an enigma for paleobotanists. This unique fossil enriches our understanding of plant evolution while asking new questions. How did this plant become extinct? What factors contributed to its disappearance?
Future research, combining fossils and genomic models, could reveal more about this fascinating species and the mysteries of the plant world. To view the full study, refer to the publication in theAnnals of Botany ici.
