A mysterious fossil plant discovered in Utah has upended botanists’ understanding of ancient plant diversity, revealing the existence of an entirely extinct plant family from 47 million years ago. This finding challenges the common assumption that most plant fossils from this era can be matched to modern families.
Published in Annals of Botany | Estimated reading time: 5 minutes
When paleobotanist Steven Manchester encountered an unusual fossil specimen in the University of California, Berkeley collection, he didn’t expect it would lead to the discovery of a lost branch on the tree of life. The specimen, named Othniophyton elongatum (meaning “alien plant”), has helped reveal that Earth’s plant diversity was even richer than previously thought.
“This fossil is rare in having the twig with attached fruits and leaves. Usually those are found separately,” explains Manchester, curator of paleobotany at the Florida Museum of Natural History.
The story began in 1969 when scientists first discovered fossilized leaves in eastern Utah’s Green River Formation. Initially, researchers thought these belonged to a member of the ginseng family (Araliaceae), based solely on leaf characteristics. However, the discovery of new specimens with preserved fruits, flowers, and stems attached has painted a dramatically different picture.
The fossils were preserved in what was once a vast inland lake system, where low-oxygen conditions and volcanic ash created perfect conditions for preserving delicate plant materials. These specimens revealed that the plant had simple rather than compound leaves, immediately ruling out its previously suggested connection to the ginseng family.
Using advanced microscopy techniques with computer-enhanced shadow effects, the research team uncovered previously invisible details about the plant’s structure. One of its most peculiar features was the retention of stamens (male reproductive organs) even after the fruits had matured – a characteristic not seen in any modern plant species.
The plant’s unique combination of features includes short-stalked elongated leaves, flowers with approximately 24 stamens, and berries containing about 15 curved seeds. Despite extensive comparisons with over 400 families of modern flowering plants, researchers couldn’t find a match. Even more surprisingly, it didn’t align with any known extinct plant families either.
This discovery challenges a common assumption in paleobotany that plant fossils from the past 65 million years should fit neatly into modern plant families. “There are many things for which we have good evidence to put in a modern family or genus, but you can’t always shoehorn these things,” Manchester notes.
The Green River Formation continues to yield similar surprises, suggesting that many more extinct plant groups await discovery. The research highlights the importance of careful observation and the willingness to challenge existing assumptions about ancient plant life.
For lead author Julian Correa-Narvaez, a doctoral student at the University of Florida, the significance extends beyond just identifying an unusual specimen. “It’s important because it gives us a little bit of a clue about how these organisms were evolving and adapting in different places,” he explains.
As digital tools make museum specimens more accessible to researchers worldwide, our understanding of plant evolution’s rich history continues to grow, revealing a more complex and diverse picture of Earth’s ancient landscapes than previously imagined.
Glossary
- Paleobotany
- The study of plant fossils and ancient plant life, providing insights into past plant diversity and evolution.
- Compound Leaves
- Leaves composed of multiple smaller leaflets, characteristic of certain plant families including the ginseng family.
- Stamens
- The male reproductive organs of a flower, typically falling away after fertilization in most modern plants.
Test Your Knowledge
How old are the Othniophyton elongatum fossils?
The fossils are approximately 47 million years old, preserved in Utah’s Green River Formation.
What key feature helped scientists determine this plant wasn’t related to the ginseng family?
The discovery of specimens with simple leaves attached directly to stems, rather than compound leaves, ruled out any connection to the ginseng family.
What unusual characteristic of the plant’s flowers makes it unique among known species?
The plant retained its stamens even after the fruits had matured, a feature not seen in any modern plant species.
Why is this discovery challenging traditional assumptions about plant fossils from this time period?
The discovery challenges the assumption that plant fossils from the past 65 million years should fit into modern plant families, suggesting greater diversity in ancient plant life than previously recognized.
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