Using two drilled core samples from northern Switzerland, researchers from the University of Zurich have unearthed flowering plant fossils dating back 240 million years. These are now the oldest known fossils of their kind. The pollen grains provide evidence that flowering plants evolved 100 million years earlier than previously thought. Researchers have described these as Angiosperm-like pollen and Afropollis from the Middle Triassic of the Termanic Basin.
Flowering plants are the result of an evolution from extinct plants related to conifers, ginkgos, cycads and seed ferns. Fossilized pollen grains provide us with the best evidence of this. Up until now, scientists have been able to document an uninterrupted sequence of pollen beginning in the Early Cretaceous period leading scientists to believe that is when flowering plants first originated. But solid evidence prior to that was heretofore not conclusive.
These newly found pollens from the core samples clearly implant the pollen fossil in the Triassic period where other studies have failed to decisively ascertain. The closest that any study has come is a 2004 study by these same determined researchers utilizing a sample extracted from the Barents Sea much further north. Researchers Professor Peter Hochuli and Susanne Feist-Burkhardt believe the newly discovered flowering plants from these pollens to be related yet different indicating a "broad ecological range".
Understandably fossils of this age are very rare. Despite that, much research has been conducted to determine the age of flowering plants based upon molecular data. But these studies have not been conclusive because the sampled molecular data has not been found "anchored" within any subject Triassic fossils, "that is why the present finding of the flowerlike pollen from the Triassic is significant," says Hochuli.
Researchers used Confocal Laser Scanning Microscopy to extract images that establish their findings. This technology allows for optical sectioning whereby data points are extracted individually and reconstructed on a computer model one section at a time to recreate a 3 dimensional image. Hochuli and research partner Feist-Burkhardt speculate on what the plants might have looked like from which the pollen came. Switzerland landscape can be described as being a drier subtropical climate during the Middle Triassic period. The structure of the pollen indicates that beetle like insects would have pollinated these flowering plants, as bees wouldn't exist for another 100 million years.
Read more from the University of Zurich.
Photo Credit: P. Hochuli and Susanne Feist-Burkhardt, University of Zurich.