An 80-million-year-old plant fossil rewrites the history of the lamiids, showing that these flowering plants, including large crops, emerged earlier than previously thought, suggesting that complex rainforests may have existed 80 million years ago. The discovery of an 80-million-year-old plant fossil traces the known origin of lamiids back to the Cretaceous period, expanding the record of nearly 40,000 species of flowering plants, including modern staple crops such as coffee, tomatoes, potatoes and mint.

Brian Atkinson, professor of ecology and evolutionary biology at the University of Kansas and curator of paleobotany at the KU Biodiversity Institute, recently published a study on a fossil plant called Palaeophytocrene chicoensis in the peer-reviewed journal Nature. plants .

“This fossil tells us a very diverse group of flowering plants that arose before our first understanding,” Atkinson said. Said. “The fossil belongs to a group of vines, woody vines that add structural complexity to rainforests. This tells us that this group of flowering plants appeared very early in the fossil record. There were some hypotheses for their existence during the Cretaceous period, but no clear evidence. It is an excellent indication that this type of structurally complex tropical forest could have existed as early as 80 million years ago.”

The fossil fruit sheds new light on a “critical juncture” in the history of life on Earth, according to a KU researcher.

“This is when forests transitioned from being dominated by gymnosperms such as conifers to dominated by flowering plants,” Atkinson said. Said. “We know that these ecological changes took place during the Late Cretaceous, but we still need important evidence, such as how some ecosystems formed, such as rainforests, which make up more than half of the plant species living today. This fossil shows that this very diverse plant group, the lamiids, is older than previously thought, and that the North American “It shows that Cretaceous ecosystems on the west coast of the continent may have resembled structurally complex tropical forests.”

The well-preserved fossil was unearthed in the 1990s by construction crews who built a residence near Granite Bay in Sacramento, California. The fossil, found in the Chico Formation sediments associated with the Campanian Period (fifth of the six years of the Late Cretaceous), was collected by Richard Hilton and Patrick Antuzzi of Sierra College and placed in the Natural History Museum.

“I spent seven years looking for these [крейдових ламіїд]and I couldn’t find them,” Atkinson said. “To better understand the evolution of flowering plants, I collected and studied Cretaceous plants on the West Coast. Someone said, “Oh, you should check out the Sierra College Natural History Museum” because I couldn’t get to them. They were happy to invite me to look at their fossil plant collections, and I was amazed by the diversity of plants these guys were able to dig up in this residential complex.”

The potential significance of the specimen became clear until Atkinson saw a fossil plant unearthed from a construction site decades ago.

“When I opened that drawer, I noticed this fruit with really impressive patterns on its surface,” said the KU researcher. I quickly realized that it belonged to a lamiid family called Icacinaceae, which is well known in younger post-Cretaceous sediments after the mass extinction. He is everywhere. However, there were no clearly known fossils belonging to this family before. “Oh my God, that’s it!” I thought. You know, this family of plants has some very impressive fruits.”

To confirm his view of the fossil, Atkinson had to take a closer look. He studied the structure of the fossil fruit using a light microscope, and this allowed him to take wonderful pictures of the specimen. By examining the arrangement of ridges, pits, rows, and tubercles, the KU researcher was able to compare it with previously identified fossils to correctly place it in the family tree. The study challenged Atkinson because he had never described such a “compression fossil”.

“I’m used to working with fossils that are preserved in a different mode called ‘mineralization,'” Atkinson said. “This is my first article on compressed fossils and it was a little frustrating because we were working on a different type of preservation than you are used to. Imaging is a completely different process – I’m glad it turned out so well.”

Atkinson, who assigned the fossil plant to the genus Palaeophytocrene, named the species chicoensis after the Chico Formation in which it was found.

“I just named the formation it was filmed in,” he said. “Part of my job is to come up with scientific names for the new species I describe, but I’m not that creative about it – I usually look for where they were discovered. Is that name already accepted?’

If the name of the fossil fruit is banal, its meaning is not. The KU researcher said the findings help identify how one of the most diverse groups of flowering plants survived the disaster that killed the dinosaurs and evolved into thousands of familiar modern species, including vital food crops for humanity.

“My research includes a deep understanding of how biodiversity is emerging today, and perhaps how it will be with climate change in the future,” Atkinson said. Said. “I was trying to characterize these evolutionary events of flowering plants during the Cretaceous period, when the diversity of these plants exploded. The Cretaceous records of the lamiids were hard to pin down, but I knew these fossils had to be there. West coast of North America compared to west interior and east coast of North America for Cretaceous plants. “As we expand our sampling geographically, we will find more plants to help us understand the Cretaceous diversity that gave rise to modern biodiversity.”