A large intact specimen of the fossil, Montsechia. Usually only small
fragmentary pieces of the fossil are found. | Photo by David Dilcher
New analysis represents major change in the presumed nature
of the planet's earliest angiosperms
(August 18, 2015) Indiana
University paleobotanist David Dilcher and colleagues in Europe have identified
a 125 million- to 130 million-year-old freshwater plant as one of earliest
flowering plants on Earth.
The finding, reported today in the Proceedings of the
National Academy of Sciences, represents a major change in the presumed form of
one of the planet’s earliest flowers, known as angiosperms.
"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," said Dilcher, an
emeritus professor in the IU Bloomington College of Arts and Sciences'
Department of Geological Sciences.
The aquatic plant, Montsechia vidalii, once grew abundantly
in freshwater lakes in what 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 country’s border with France.
Illustrations based on fossilized remains show long- and short-leaved
forms of the plant
and a single seed. | Photo by Oscar Sanisidro
Also previously proposed as one of the earliest flowers is
Archaefructus sinensis, an aquatic plant found in China.
"A 'first flower' is technically a myth, like the
'first human,'" said Dilcher, an internationally recognized expert on
angiosperm anatomy and morphology who 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 also asserted that the fossils used in the study were
"poorly understood and even misinterpreted" during previous analyses.
"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."