A lack of dinosaurs traipsing around following the K-T mass extinction may have allowed the grape we know and love to spread and thrive. A team of researchers found fossilized grape seeds dating back 60 to 19 million years old in Colombia, Panama, and Peru. The find includes the oldest known example of plants from the grape family in the Western Hemisphere and tells some parts of the grape’s evolutionary story for the first time. The grapes-for-dinosaurs exchange is detailed in a study published July 1 in the journal Nature Plants.
“These are the oldest grapes ever found in this part of the world, and they’re a few million years younger than the oldest ones ever found on the other side of the planet,” Fabiany Herrera, a study co-author and assistant curator of paleobotany at the Field Museum’s Negaunee Integrative Research Center, said in a statement. “This discovery is important because it shows that after the extinction of the dinosaurs, grapes really started to spread across the world.”
A forest reset
Usually, soft tissues like fruits are not preserved as fossils. Seeds are often how paleobotanists study ancient plants since they are more likely to fossilize. The earliest known grape seeds are roughly 66 million years old, just about when an enormous asteroid hit the Earth triggering mass extinction. Not only were the dinosaurs and an estimated 95 percent of species on Earth were wiped out, but the forest reset and changed the composition of the planet’s plants. The team hypothesizes that the disappearance of the dinosaurs may have helped change the forests.
“Large animals, such as dinosaurs, are known to alter their surrounding ecosystems,” Mónica Carvalho, a study co-author and assistant curator at the University of Michigan’s Museum of Paleontology, said in a statement. “We think that if there were large dinosaurs roaming through the forest, they were likely knocking down trees, effectively maintaining forests more open than they are today.”
[Related: Fossilized plants give us hints about what ice age forests may have looked like.]
However, without hulking dinosaurs skulking about to prune them, some tropical forests–including those in modern South America–became more crowded. Layers of trees eventually formed an understory and a canopy and these new dense forests were ripe with opportunity for some plants.
“In the fossil record, we start to see more plants that use vines to climb up trees, like grapes, around this time,” says Herrera.
The bird and mammal species that diversified in the years that followed may have also helped the grapes by spreading around their seeds. A 2013 study described the oldest known grape fossils that were found in India. At the time, grape seeds had yet to be found in South America, but Herrera suspected that they could be there.
“Grapes have an extensive fossil record that starts about 50 million years ago, so I wanted to discover one in South America, but it was like looking for a needle in a haystack,” says Herrera. “I’ve been looking for the oldest grape in the Western Hemisphere since I was an undergrad student.”
A stone seed
In 2022 Herrera and Carvalho were conducting fieldwork in the Colombian Andes. A fossil caught Carvalho’s eye and it turned out to be the remains of a 60-million-year-old grape seed. It was not only the first South American grape fossil ever found, but is among the oldest in the world.
Despite being tiny, the team were able to identify it based on its shape, size, and other physical features. They also conducted CT scans in the lab that showed its internal structure. They named the fossil Lithouva susmanii–Susman’s stone grape–in honor of Arthur T. Susman, a supporter of South American paleobotany at the Field Museum.
“This new species is also important because it supports a South American origin of the group in which the common grape vine Vitis evolved,” study co-author Gregory Stull of the National Museum of Natural History said in a statement.
[Related: Fossil first identified as plant is actually a baby turtle.]
Additional field work in South and Central America led to the description of nine new species of fossil grapes from Colombia, Panama, and Peru. The fossils are distant relatives of the grapes that are native to the Western Hemisphere. Some of the species including two species of Leea are only found in the Eastern Hemisphere today. Their positions within the grape family tree indicate that their evolutionary journey has been rather tumultuous.
“The fossil record tells us that grapes are a very resilient order,” said Herrera. “They’re a group that has suffered a lot of extinction in the Central and South American region, but they also managed to adapt and survive in other parts of the world.”
