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

If you’ve ever eaten raisins or enjoyed a glass of wine, it might be partly because of the extinction of the dinosaurs. In a discovery described in the journal Nature Plantsresearchers have discovered fossilized 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 grape family plant in the Western Hemisphere. These fossil seeds help show how the grape family spread in the years after the dinosaurs died out.

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

It’s rare for soft tissues like fruits to be preserved as fossils, so scientists’ understanding of ancient fruits often comes from seeds, which are more likely to fossilize. The earliest known grape seed fossils were found in India and date back 66 million years. It’s no coincidence that grapes first appeared in the fossil record 66 million years ago: that’s around the time a massive asteroid struck Earth, triggering a mass extinction that changed the course of life on the planet.

“We always think of animals, dinosaurs, because they were the ones that were most affected, but the extinction also had a huge impact on plants,” Herrera says. “The forest regenerated, which changed the composition of the plants.”

Herrera and his colleagues hypothesize that the disappearance of dinosaurs may have helped change forests. “Large animals, like dinosaurs, are known to modify the ecosystems around them. We think that if large dinosaurs roamed the forest, they probably cut down trees, which helped keep forests more open than they are today,” explains Mónica Carvalho, co-author of the study and assistant curator at the University of Michigan Museum of Paleontology.

But without large dinosaurs to carve them out, some rainforests, notably those in South America, became more densely populated, with layers of trees forming an understory and canopy.

These new dense forests paved the way for such an evolution. “At this time, fossils show that more and more plants climbed trees using lianas, such as vines,” says Herrera. The diversification of birds and mammals in the years following the mass extinction may also have helped the spread of the vine.

In 2013, Herrera’s Ph.D. advisor and lead author of the new paper, Steven Manchester, published a paper describing the oldest known grape seed fossil, from India. Although no fossil grapes have ever been found in South America, Herrera suspected they might be there, too.

“Grapes have a lot of fossils that started 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 says. “I’ve been looking for the oldest grape in the Western Hemisphere since I was an undergraduate.”

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

The fossil seed itself is tiny, but Herrera and Carvalho were able to identify it based on its particular shape, size and other morphological characteristics. Back in the lab, they performed CT scans showing its internal structure that confirmed its identity.

The team named the fossil Lithouva susmanii, “Susman’s stone grape,” in honor of Arthur T. Susman, a proponent of South American paleobotany at the Field Museum. “This new species is also important because it confirms the South American origin of the group in which the common grapevine Vitis evolved,” said Gregory Stull, a co-author of the study and a fellow at 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, ranging in age from 60 million to 19 million years old. These fossilized seeds tell not only the story of the grape’s spread across the Western Hemisphere, but also the many extinctions and dispersals the grape family has experienced.

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

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

Given the mass extinction our planet is currently facing, Herrera believes studies like this are valuable because they reveal patterns in how biodiversity crises occur. “But the other thing I love about these fossils is that these humble little seeds can tell us a lot about how the forest evolved,” Herrera says.

This study was authored by 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 (Museum of Natural History of Florida, University of Florida).