Sixty-million-year-old grape seeds reveal how the extinction of dinosaurs may have paved the way for the spread of grapes

If you’ve ever snacked on raisins or drank a glass of wine, you can, in part, thank the extinction of the dinosaurs. In a discovery reported in the journal Nature plantsresearchers have discovered fossil grape seeds that are 60 to 19 million years old in Colombia, Panama and Peru. One of these species represents the earliest known example of a vine plant in the Western Hemisphere. These fossilized seeds help show how the vine family spread in the years after the dinosaurs died.

“These are the oldest grapes ever found in this part of the world, and they are several million years younger than the oldest grapes found on the other side of the planet,” says Fabiany Herrera, assistant curator of paleobotany at the Field Museum at Chicago’s Negaunee Integrative Research Center and lead author of the paper . “This discovery is important because it shows that after the dinosaurs became extinct, grapes really began to spread around the world.”

Soft tissues like fruit are rarely preserved as fossils, so scientists often rely on seeds, which are more likely to fossilize. The earliest known grape seed fossils were found in India and are 66 million years old. It’s no coincidence that grapes first appeared in the fossil record 66 million years ago—around the time a massive asteroid hit Earth, causing a mass extinction that changed the course of life on the planet.

“We always think about animals, dinosaurs, because they suffered the most, but the extinction also had a huge impact on plants,” Herrera says. “The forest reset in a way that changed the plant composition.”

Herrera and his colleagues hypothesize that the disappearance of the dinosaurs may have changed the forests. “It’s known that large animals like dinosaurs change the ecosystems around them. We think that if there were large dinosaurs running around in the forest, they would have likely knocked down trees, effectively keeping the forests more open than they are today,” says Mónica Carvalho, a co-author of the paper and an assistant curator at the University of Michigan Museum of Paleontology.

But without large dinosaurs to trim these trees, some tropical forests, including those in South America, became denser, with layers of trees forming the understory and canopy.

These new, dense forests provided an opportunity. “We start to see more plants in the fossil record that use vines to climb trees, like grapes, around this time,” Herrera says. The diversification of birds and mammals in the years following the mass extinction may also have helped grapes by spreading their seeds.

In 2013, Herrera’s doctoral advisor and senior author of the new paper, Steven Manchester, published a paper describing the oldest known fossil grape seed, from India. Although no fossil grapes had ever been found in South America, Herrera suspected there might be some.

“Grapes have a vast fossil record that goes back about 50 million years, so I wanted to find one in South America, but it was like finding a needle in a haystack,” Herrera says. “I’ve been looking for the oldest grapes in the Western Hemisphere since I was a graduate student.”

But in 2022, Herrera and his co-author Mónica Carvalho were doing fieldwork in the Colombian Andes when Carvalho spotted the fossil. “She looked at me and said, ‘Fabiany, a grape!’ And then I looked at her and thought, ‘Oh my God.’ It was so exciting,” Herrera recalls. The fossil was in 60-million-year-old rock, making it not only the first South American grape fossil but also one of the oldest grape fossils in the world.

The fossilized seed itself is tiny, but Herrera and Carvalho were able to identify it based on its peculiar shape, size, and other morphological features. They returned to the lab and performed a CT scan, revealing its internal structure, which confirmed its identity.

The team named the fossil Lithouva susmanii, “Susman’s stone grape,” after Arthur T. Susman, a supporter of South American paleobotany at the Field Museum. “This new species is also important because it confirms the South American origins of the group in which the common Vitis vine evolved,” says co-author Gregory Stull of the National Museum of Natural History.

The team conducted further fieldwork in South and Central America, and in the Nature Plants paper, Herrera and his co-authors ultimately described nine new species of fossil grapes from Colombia, Panama and Peru, dating from 60 to 19 million years ago. These fossilized seeds not only tell the story of the spread of grapes throughout the Western Hemisphere, but also the many extinctions and dispersals that the grape family has experienced.

The fossils are only distant relatives of grapes native to the Western Hemisphere, and a few, like two species of Leea, are found only in the Eastern Hemisphere. Their place in the grape family tree indicates that their evolutionary journey has been a tumultuous one.

“The fossil record tells us that grapes are a very resilient species. It’s a group that experienced significant extinction in the Central and South American region but also managed to adapt and survive in other parts of the world,” Herrera says.

Given the mass extinction our planet is currently facing, Herrera says studies like this are valuable because they reveal patterns in how biodiversity crises play out. “But the other thing I like about these fossils is that these little, humble seeds can tell us so much about the evolution of the forest,” Herrera says.

The authors of this study are Fabiany Herrera (Field Museum), Mónica Carvalho (University of Michigan), Gregory Stull (National Museum of Natural History, Smithsonian Institution), Carlos Jarramillo (Smithsonian Tropical Research Institute) and Steven Manchester (Florida Museum of Natural History, University of Florida).