A research group from China and Germany discovered fossilized starch dating back at least 280 million years, the earliest record of such a fossil to date.
Scientists found lycopsid megaspores bearing caps of granular material in a coal bed in Baode County, north China's Shanxi Province, said the Nanjing Institute of Geology and Palaeontology Tuesday.
X-ray analysis and microimaging revealed these lycopsid megaspores consist of carbon and oxygen. They show remarkable similarity with starch grains of extant plants in size, shape, and optical properties, indicating that they were starch granule between 280 and 290 million years ago.
Usually, starch in soils can hardly be preserved for over 600 years without the protection of stoneware. But according to Liu Feng with the institute, which is under the Chinese Academy of Sciences, the coal bed had possibly created an environment that inhibited the breakdown of starch by fungus, water and other bacteria.
Scientists have found the starch very similar to an edible part of the elaiosomes on seeds of modern plants, which rely on animals to disperse their seeds.
The similarity indicated that far before the appearances of birds and ants, some Permian lycopsids had been capable of conducting photosynthesis and storing glucose in the form of starch.
"The plants had established a plant-animal mutualism and attracted snails, cockroaches and other land life with starch to help disperse their spores," Liu said.
The findings were published in the latest issue of the journal Geology.