Recent Study Finds Montsechia to be Earth's First Flower
Paleobontanist David Dilcher recently found Montsechia vidalii to be the Earth's earliest freshwater flowering plant, coming in at about 125 to 130 million years old. This discovery changes the previous belief that angiosperms are the planet's earliest flowers.
"This discovery raises significant questions about the early evolutionary history of flowering plants, as well as the role of these plants in the evolution of other plant and animal life," Dilcher said in a statement. Dilcher is an emeritus professor in the Indiana University Department of Geological Sciences.
Dilcher's research, published in the Proceedings of the National Academy of Sciences, found Montsechia vidalii to be more ancient than Archaefructus sinensis, an aquatic plant found in China. Montsechia vidalii is an aquatic plant that once grew abundantly in freshwater lakes--which are now mountainous regions in Spain. Fossils of the plant were first discovered more than 100 years ago in the limestone deposits of the Iberian Range in central Spain, and in the Montsec Range of the Pyrenees, near the border with France.
"A 'first flower' is technically a myth, like the 'first human,'" said Dilcher, who is an internationally recognized expert on angiosperm anatomy and morphology, and has studied the rise and spread of flowering plants for decades. "But based on this new analysis, we know now that Montsechia is contemporaneous, if not more ancient, than Archaefructus." He explained that fossils used in previous studies were "poorly understood and even misinterpreted," according to the statement.
In his work, Dilcher analyzed more than 1,000 fossilized remains, applying hydrochloric acid drop by drop to coax stem and leaf structures from stone. He also bleached the plant's cuticles -- the protective film covering the leaves that reveals their shape -- using a nitric acid and potassium chlorate mixture. To examine each specimen, Dilcher used a stereomicroscope, light microscope and scanning electron microscope, the release noted.
"The reinterpretation of these fossils provides a fascinating new perspective on a major mystery in plant biology," said Donald H. Les, a professor of ecology and evolutionary biology at the University of Connecticut, who is the author of a commentary on the discovery in the journal PNAS. "David's work is truly an important contribution to the continued quest to unravel the evolutionary and ecological events that accompanied the rise of flowering plants to global prominence."
The study determined the plants age by comparing it with other fossils in the same area, including the freshwater algae charophytes -- which places Montsechia in the Barremian age of the early Cretaceous period, making it a contemporary of the brachiosaurus and iguanodon, the release noted.
Dilcher's careful examination was necessary for reidentifying Montsechia, because many modern observers wouldn't have even recognized the fossil as a flowering plant. In fact, precise analysis of fossilized structures is a crucial aspect of paleobotany.
"Montsechia possesses no obvious 'flower parts,' such as petals or nectar-producing structures for attracting insects, and lives out its entire life cycle under water," he said in a release of his study. "The fruit contains a single seed" -- the defining characteristic of an angiosperm -- "which is borne upside down."
In terms of appearance, Montsechia most resembles its modern descendent, Ceratophyllum, also identified in the study and more commonly recognized as coontails or hornworts. Ceratophyllum is a dark green aquatic plant whose coarse, tufty leaves make it a popular decoration in modern aquariums and koi ponds. For future discovery, Dilcher hopes to understand the connection between Montsechia and Ceratophyllum, the release said.