Paleontologists Find 18.5-Million-Year-Old Liana Fossil
Paleontologists have discovered what they say is the oldest macrofossil evidence of Paullinieae, a diverse group of tropical and subtropical climbing plants that belong to the soapberry family Sapindaceae.
Paullinieae are tropical and subtropical woody vines, herbaceous climbers, and seldom shrubs.
With six genera and 475 species, they comprise nearly one quarter of all species in the Sapindaceae family.
Although the fossil record of Sapindaceae is rich, Paullinieae macrofossils are extremely rare.
The newfound Paullinieae fossils are roots, but nonetheless provide strong evidence of the climbing habit based on wood anatomy associated with climbing in Sapindaceae.
“This is evidence that lianas have been creating unusual wood, even in their roots, as far back as 18 million years ago,” said Dr. Joyce Chery, a wood anatomist in the School of Integrative Plant Sciences at Cornell University.
“Before this discovery, we knew almost nothing about when or where these lianas evolved or how rapidly they diversified,” added Dr. Nathan Jud, a plant biologist at William Jewell College and the Florida Museum of Natural History.
The 18.5-million-year-old fossils of the new species, named Ampelorhiza heteroxylon, were recovered from the Cucaracha Formation in Panama.
“Panama was a peninsula 18.5 to 19 million years ago, a volcanic landscape covered with tropical forest in North America and separated from South America by a Central American seaway,” Dr. Jud said.
“While these forests contained North American animals, the plants mostly descended from South American tropical plants that had dispersed across the seaway.”
“The fossil we described is the oldest macrofossil of these vines, and they were among the plants that made it to North America long before the Great American Biotic Interchange when large animals moved between the continents some 3 million years ago.”
The findings were published in the journal PLoS ONE.
N.A. Jud et al. 2021. Climbing since the early Miocene: The fossil record of Paullinieae (Sapindaceae). PLoS ONE 16 (4): e0248369; doi: 10.1371/journal.pone.0248369