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Grapes have been intertwined with human history for millennia, providing the basis for the wines produced by our ancestors thousands of years ago – but this may not have been the case if the dinosaurs had not disappeared from the planet, according to new research.

When an asteroid hit Earth 66 million years ago, it wiped out the massive, lumbering animals and set the stage for other creatures and plants to flourish afterward.

Now the discovery of fossilized grape seeds in Colombia, Panama and Peru, which are 19 million to 60 million years old, is shedding light on how these humble fruits gained a foothold in Earth’s dense forests and eventually established a global presence. One of the newly discovered seeds is the oldest example of a grape family plant found in the Western Hemisphere, according to a study of the specimens published Monday in the journal Nature Plants.

“These are the oldest grape varieties ever found in this part of the world, and are several million years younger than the oldest ever found on the other side of the planet,” said study lead author Fabiani Herrera, associate curator of Paleobotany at the Field Museum at Chicago’s Negaunee Integrative Research Center, in a statement. “This discovery is important because it shows that after the extinction of the dinosaurs, grapes really began to spread around the world.”

Like the soft tissues of animals, true fruits do not preserve well in fossils. But seeds that are more likely to fossilize can help scientists understand what plants were present at different stages of Earth’s history as they reconstruct the tree of life and establish origin stories.

The oldest grape seed fossils ever found were found in India and date back to 66 million years ago, roughly the time of the dinosaurs’ demise.

“We always think about the animals, the dinosaurs, because they were the most affected things, but the extinction had a huge impact on the plants as well,” Herrera said. “The forest rearranged itself in a way that changed the composition of the plants.”

Herrera’s doctoral advisor, Steven Manchester, who is also senior author of the new study, published a paper on the grape fossils found in India. This inspired Herrera to wonder where other grape seed fossils might exist, such as South America, even though they had never been found there.

“The grape has an extensive fossil record that starts about 50 million years ago, so I wanted to find one in South America, but it was like looking for a needle in a haystack,” Herrera said. “I’ve been looking for the oldest grape in the Western Hemisphere since I was a student.”

Herrera and study co-author Monica Carvalho, assistant curator at the University of Michigan Museum of Paleontology, were doing fieldwork in the Colombian Andes in 2022 when Carvalho spotted a fossil. It turned out to be a 60-million-year-old grape seed fossil trapped in rock, among the oldest in the world and the first to be found in South America.

“She looked at me and said, ‘Fabiani, grapes!’ And then I looked at him and I was like, ‘Oh my God.’ It was so exciting,” Herrera said.

Although the fossil is small, its shape, size and other characteristics helped the duo identify it as a grape seed. And after returning to the laboratory, the researchers performed a CT scan to study its internal structure and confirm their findings.

They named the newly discovered species Lithouva susmanii, or “Susman’s Stone Grape,” in honor of Arthur T. Susman, who was a supporter of South American paleobotany at the Field Museum.

“This new species is also important because it supports a South American origin for the group in which the common Vitis vine evolved,” said study co-author Gregory Stull of the National Museum of Natural History.

The rocks were deposited in ancient lakes, rivers and coastal areas, Herrera said.

“To look for such tiny seeds, I split open every available piece of rock in the field,” he said, adding that the difficult search “is the fun part of my job as a paleobotanist.”

Encouraged by their find, the team conducted more fieldwork in South and Central America and discovered nine new species of fossil grape seeds trapped in sedimentary rocks. And by tracing the lineage of the ancient seeds to their modern grape counterparts, the team realized that something allowed the plants to thrive and spread.

The team’s hypothesis is that when the dinosaurs went extinct, their absence changed the entire structure of the forests.

“Large animals such as dinosaurs are known to change the ecosystems around them. “We think that if there were large dinosaurs roaming the forest, they probably felled trees, effectively keeping the forests more open than they are today,” Carvalho said.

After the dinosaurs went extinct, the rainforests were overgrown and layers of trees created the understory and canopy. These dense forests made it difficult for plants to receive light and they had to compete with each other for resources. And creepers had an advantage and used it to reach the crown, the researchers said.

“In the fossil record, we’re starting to see more plants that used vines to climb trees, like grapes, at that time,” Herrera said.

Meanwhile, as a diverse array of birds and mammals began to populate Earth after the dinosaurs went extinct, they probably also helped spread grape seeds.

The study of the seeds tells a story of how the grape spread, adapted and disappeared over thousands of years, demonstrating its resilience to survive in other parts of the world despite disappearing from Central and South America over time.

Several fossils are related to modern grapes, while others are distant relatives or grapes native to the Western Hemisphere. For example, some of the fossil species can be traced back to grapes that today are found only in Asia and Africa, but it’s not clear why grapes became extinct in Central and South America, Herrera said.

“The new fossil species tell us a turbulent and complex story,” he said. “We usually think of diverse and modern rainforests as a ‘museum’ model where all species accumulate over time. However, our study shows that extinction is a major force in the evolution of tropical forests. Now we need to identify what caused these extinctions over the past 60 million years.

Herrera wants to look for other examples of fossil plants, such as sunflowers, orchids and pineapples, to see if they existed in ancient rainforests.

Studying the origins and adaptations of plants in the past helps scientists understand how they might cope during the climate crisis.

“I just hope that most living plant seeds adapt quickly to the current climate crisis.” “Seed fossils tell us that plants are resilient, but they can also completely disappear from an entire continent,” Herrera said.