Until recently, it was thought that grape plants first appeared in Europe less than 23 million years ago. However, a recent study on fossil plants presents a different perspective, suggesting that the ancestors of grape plants were actually present in Europe around 41 million years ago. This research highlights a newly discovered fossil species, Nekemias mucronata, which sheds light on the evolutionary journey of this plant family that thrived in Europe from 40 to 23 million years ago.
It was once believed that grape family plants arrived on the European continent less than 23 million years ago. Recent research on fossil plants has shifted this view, indicating that ancestors of grape plants were already present in Europe about 41 million years ago. This study identifies a new fossil species, Nekemias mucronata, which enhances our understanding of the evolutionary path of this plant group that existed in Europe between 40 and 23 million years ago.
This research, published in the Journal of Systematics and Evolution (JSE), is led by Aixa Tosal from the Faculty of Earth Sciences and the Biodiversity Research Institute (IRBio) at the University of Barcelona. The article also includes contributions from Alba Vicente of the Biodiversity Research Institute (IRBio) and the Catalan Institute of Palaeontology Miquel Crusafont (ICP), along with Thomas Denk from the Swedish Museum of Natural History in Stockholm.
A new ancestor of the grape family
The grape family (Vitaceae) includes approximately 950 species and is categorized into five tribes, which are taxonomic groups that sit between family and genus. One of these tribes, Viteae, consists of 200 species, among which is the economically significant grape vine (Vitis vinifera). The new research focuses on the tribe Ampelopsideae, which contains 47 species.
“Our study challenges the previously accepted views and reveals that the Ampelopsis and Nekemias lineages within the Ampelopsideae tribe were already established in Europe and Central Asia during the middle Eocene (between 47 and 37 million years ago). This suggests they spread about 20 million years earlier than previously thought,” states Aixa Tosal, the lead author from UB’s Department of Earth and Ocean Dynamics.
“Notably, our findings indicate that a lineage currently found only in North America was already present in Europe and Central Asia, as evidenced by the discovery of the fossil species Nekemias mucronata, which closely resembles the North American Nekemias arborea. The fossil Nekemias mucronata coexisted with Ampelopsis hibschii, its nearest relative to today’s Ampelopsis orientalis,” Tosal elaborates. Conversely, Ampelopsis orientalis took a different dispersal route and is now only found in the eastern Mediterranean. “This research enhances our understanding of the evolution of the Ampelopsideae tribe during the second wave of dispersal, particularly in Europe and Central Asia, during the Palaeogene,” Tosal adds.
Nekemias mucronata thrived from the late Eocene to the late Oligocene (37-23 million years ago). It appears to have flourished in a variety of climates, ranging from regions with low winter temperatures (as low as -4.6 °C, found in Kazakhstan during the Oligocene) to warmer areas in the Iberian Peninsula during the Oligocene, as well as regions with moderate temperatures in central Europe.
“N. mucronata was not particularly demanding regarding rainfall, growing in regions with both high rainfall and low rainfall variability, such as Central Europe during the Oligocene, as well as the Iberian Peninsula and Greece during the same period,” notes Alba Vicente from ICP. “This fossil species featured a compound leaf structure, a trait shared by several species in the vine family. While determining the exact number of leaflets is challenging, it’s likely that each leaf had at least three. We have identified shared characteristics between the apical and lateral leaflets, which distinguish them from other fossil vine species in Eurasia,” she explains. “What makes Nekemias mucronata stand out is the mucro at the apex of the leaflet teeth, which gives the species its name. The straight shape of the base of the apical leaflet is also quite unique, contrasting with other Eurasian fossil species, which typically feature a notch near the petiole,” Vicente adds.
Dispersal of Ampelopsideae across the Atlantic bridge or the Bering Strait
The most ancient records of the grape family have been located in the Upper Cretaceous deposits of India (75-65 million years ago). The earliest evidence of the lineage in the Americas dates back to the Upper Eocene, around 39.4 million years ago, while the Ampelopsis and Nekemias lineages were present in Europe and Central Asia around the same time.
How did these species spread in the past? The divergence of these tribes is believed to have occurred between the Upper Cretaceous and Upper Eocene, and although many aspects remain unclear, they seem to have dispersed and evolved rapidly. Present data, which align with molecular clock techniques, suggest that Ampelopsideae could have taken one of two migratory paths or a combination of both. The first proposed route suggests that the family originated in India and then migrated to central Asia and Europe during the middle Eocene (47-37 million years ago), before continuing to the Americas via Greenland,” explains Thomas Denk. “Alternatively, once the Vitaceae family emerged in India, the Ampelopsideae tribe may have expanded eastward from Asia during the middle Eocene (47-37 million years ago) and subsequently reached the Americas via the Bering Strait, eventually arriving in Europe along the North Atlantic isthmus,” Denk suggests.
While the dispersal of these two species does not appear to be directly linked to climate changes, the increasing aridity during the Oligocene in the Iberian Peninsula and southern Europe may offer an explanation for the extinction (27-23 million years ago) of the last known population of N. mucronata in this region. At the same time, Ampelopsis hibschii was limited to the Balkan area and eventually went extinct around 15 million years ago.
“Nevertheless, many questions remain about the initial phases of dispersal (from the Late Cretaceous to the Palaeogene). Therefore, we aim to continue our studies on this family, hopefully uncovering more insights about what transpired during their early clustering phases, occurring between 66 and 41 million years ago,” the research team concludes.
