Ann Arbor Times

The ancestor of Vitoid grapes that gave rise to commercial grapes likely originated in the New World, specifically in the tropical belt of the Americas and the Caribbean, 60 million years ago. This conclusion comes from a study co-authored by a University of Michigan researcher.

Researchers discovered fossilized seeds representing nine separate species of grape ranging in age from about 20 million to 60 million years old in Panama, Colombia, and Peru. The oldest of these fossilized seeds came from plants related to the current subfamily Vitoideae, which includes commercial grapes, according to U-M paleobotanist Mónica Carvalho, co-author of the study published in Nature Plants.

“In excavating the fossil record in the New World tropics, we found seeds that are related to the grape family that date back to 60 million years ago. That led us to revise the fossil record of grapes in the New World. The oldest seed we found is closely related to the large group that gave rise to commercial grapes, to the subfamily Vitoideae,” said Carvalho, assistant professor of earth and environmental sciences and an assistant curator at the U-M Museum of Paleontology.

“We have this rich but previously poorly known fossil record for grapes in the New World, and what we’re seeing is this family has a complex history of extinction and dispersal in the New World. Various groups of this family, such as the genus Leea and species of tribe Cayrateae only live today in Southeast Asia and the Indo-Pacific, but their fossils indicate that they lived in the New World for a very long time before becoming regionally extinct.”

Approximately 66 million years ago, at the end of the Cretaceous Period, an asteroid hit Earth. This event caused significant extinctions including dinosaurs and “pretty much wiped out a lot of the preexisting forests that were living in the tropical latitudes of the New World,” Carvalho says.

New rainforests grew in place of these destroyed landscapes and prompted diversification among many modern plant and animal groups. Carvalho and lead author Fabiany Herrera, a paleobotanist at Chicago's Field Museum of Natural History, examined fossil records from this period to understand modern rainforest evolution.

“Within these early neotropical rainforests, we find the earliest record of Vitoideae, telling us that the lineage of grapes dates back to the origin of the first neotropical rainforests,” Carvalho said.

Herrera noted that this discovery is significant “because it shows that after extinction events like those involving dinosaurs, grapes really started to spread across different parts of world.”

The grape family has an extensive fossil record predating even earlier extinction events. According to Carvalho, some ancient grape fossils found in India date back to when dinosaurs roamed Earth. Seeds from these plants may have been transported by animals across continents.

“The diversification of birds and mammals following end-Cretaceous extinctions could have aided in dispersing their seeds,” Herrera added.

Carvalho emphasized how their study fills gaps regarding grape history within Americas and Caribbean regions: “There was a very large gap post-dinosaur extinction until about 50 million years ago when we see fossil evidence appearing again within North America & Europe...our work addresses understanding their history particularly within tropical latitudes."