Death of dinosaurs helped spread grapes, reveal 60-million-year-old seeds

“This discovery is important because it shows that after the extinction of the dinosaurs, grapes really started to spread across the world,” said Fabiany Herrera, an assistant curator of paleobotany at the museum and lead author of the paper. 

First and oldest grape seeds in South America

Paleobotanist Herrera has been hunting for clues about the ancient fruits through tiny seed fossils. 

Ancient fruits are often difficult to uncover since soft fruits are not preserved as fossils therefore experts look for seeds. 

Grapes have an excellent fossil record going back 50 million years. Interestingly, the oldest grape seed fossils discovered in India are around 66 million years old, corresponding with the catastrophic asteroid impact that changed Earth’s existence.

For years, Herrera had a hunch that grapes existed in South America millions of years ago. Finally, Herrera’s persistence paid off. He and his team found grape seeds in rocks as old as 60 million. 

“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,” said Herrera. 

Change of ancient forest ecosystems

The researchers state that the extinction events shake things up for plants, too. They hypothesize that the dinosaurs’ demise might have catalyzed forest change.

“Large animals, such as dinosaurs, are known to alter their surrounding ecosystems. 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,” said Mónica Carvalho, a co-author of the paper and assistant curator at the University of Michigan’s Museum of Paleontology. 

Researchers believe the absence of these large herbivores allowed tropical forests to become denser in South America. Without dinosaurs munching and knocking down trees, the forests developed a thicker understory and extensive canopy layer.

This also created opportunities for various plant species to grow and thrive. The woodlands provided an ideal setting for climbing vines such as grapes. Moreover, ancient birds and mammals also played a role, helping to spread grape seeds far and wide.

“In the fossil record, we start to see more plants that use vines to climb up trees, like grapes, around this time,” said Herrera. 

The researchers thoroughly examined the ancient seeds using CT scans to disclose their interior structure. The fossils’ form, size, and other morphological characteristics revealed that they belonged to a new grape species. 

These newly discovered fossils are like tiny time capsules, holding secrets about grapes’ history, including the extinction events. 

“The fossil record tells us that grapes are a very resilient order. 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,” concluded Herrera in the press release. 

The findings have been reported in the journal Nature Plants.