A dinosaur-era freshwater plant from Spain has just been identified as the world's oldest known flowering plant.
The plant Montsechia vidalii, described in the latest issue of the Proceedings of the National Academy of Sciences, has been dated to approximately 130 million years ago when dinosaurs were Earth's dominant land animals.
The Cretaceous Period plant once grew abundantly in freshwater lakes in what are now mountainous regions in Spain. It slightly edges out another early flowering plant, China's Archaefructus sinensis, as being the earliest known flower. Like Montsechia, Archaefructus was an aquatic species.
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"A ‘first flower' is technically a myth, like the ‘first human,'" co-author David Dilcher, a paleobotanist at Indiana University, said in a press release. "But based on this new analysis, we know now that Montsechia is contemporaneous, if not more ancient, than Archaefructus."
Dilcher and an international team of researchers analyzed more than 1,000 fossilized remains of Montsechia. They applied hydrochloric acid drop by drop to stones containing the plants, in order to reveal the precise structures of stems and leaves. A mixture of nitric acid and potassium chlorate was also used to unveil the shape of the plant's cuticles. These are the protective films that cover leaves.
All of the above was done under extremely high magnification, allowing the scientists to see every fossilized detail.
As for dating the plant remains, the researchers compared them to other fossils in the same area, such as those for the freshwater algae charophytes. Based on the determined age, the flowering plant co-existed with dinosaurs, such as Brachiosaurus and Iguanodon.
Montsechia was classified as a flowering plant (angiosperm) because it produced seeds enclosed within a carpel. A carpel, in turn, is the female reproductive organ of a flower.
"Montsechia possesses no obvious ‘flower parts,' such as petals or nectar-producing structures for attracting insects, and lived out its entire life cycle under water," Dilcher said. "The fruit contains a single seed" - the defining characteristic of an angiosperm - "which is borne upside down."
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The modern descendant of this ultra ancient plant is Caratophyllum, otherwise known as coontails or hornworts. It is a dark green aquatic plant that is popularly used in aquariums and koi ponds because of its decorative coarse, tufty leaves.
Dilcher and his colleagues continue to study early plants, hoping to learn more about their evolution.
He explained, "There's still much to be discovered about how a few early species of seed-bearing plants eventually gave rise to the enormous, and beautiful, variety of flowers that now populate nearly every environment on Earth."