A surprising fossil plant unearthed in Utah has revolutionized botanists’ understanding of ancient plant diversity by revealing the existence of a completely extinct plant family dating back 47 million years. This discovery challenges the commonly held belief that most plant fossils from that era can be linked to modern families.
Published in Annals of Botany | Estimated reading time: 5 minutes
When paleobotanist Steven Manchester came across a peculiar fossil specimen in the University of California, Berkeley collection, he never expected it would uncover a lost branch on the tree of life. Named Othniophyton elongatum (meaning “alien plant”), the specimen has played a key role in demonstrating that Earth’s plant diversity was even more diverse than previously thought.
“This fossil is unique in having both the twig with attached fruits and leaves. Usually, these are found separately,” explains Manchester, the curator of paleobotany at the Florida Museum of Natural History.
The saga began in 1969 when researchers initially identified fossilized leaves in Utah’s Green River Formation. At first, they believed these belonged to a member of the ginseng family (Araliaceae) based on leaf characteristics alone. However, the discovery of new specimens with preserved fruits, flowers, and stems attached revealed a significantly different story.
The fossils were preserved in what was once a vast inland lake system, where ideal conditions created by low oxygen levels and volcanic ash allowed for the preservation of delicate plant materials. These specimens showed that the plant had simple leaves instead of compound leaves, immediately dispelling its previously suggested connection to the ginseng family.
Through advanced microscopy techniques with computer-enhanced shadow effects, the research team uncovered previously unseen details about the plant’s structure. One of its most notable features was the retention of stamens (male reproductive organs) even after the fruits had matured – a trait not observed in any modern plant species.
The plant’s distinctive features include short-stalked elongated leaves, flowers with around 24 stamens, and berries containing about 15 curved seeds. Despite extensive comparisons with more than 400 families of modern flowering plants, researchers were unable to find a match. Surprisingly, it did not align with any known extinct plant families either.
This discovery challenges the common assumption in paleobotany that plant fossils from the past 65 million years should neatly fit into modern plant families. Manchester notes, “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.”
The ongoing surprises from the Green River Formation suggest that many more extinct plant groups are waiting to be discovered. This research underscores the significance of attentive observation and the willingness to question existing assumptions about ancient plant life.
For lead author Julian Correa-Narvaez, a doctoral student at the University of Florida, the importance goes 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 the rich history of plant evolution continues to expand, revealing a more intricate and diverse depiction of Earth’s ancient landscapes than previously envisioned.
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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