This is
important. Kicking the evolution of
flowering plants back into the Triassic or another hundred million years
further back is a pleasant surprise and changes our viewpoint as this is a
rapid means of advancing plant evolution.
Figuring out how
it all happened and where is quite another question. We hardly understand just how plant diversity
properly arises to begin with except to observe whenever we change something
something new seems to happen.
In the event flowering
plants now belong back in the Triassic.
Fossils push
flowering plants back to early Triassic
by Staff Writers
Zurich, Switzerland (SPX) Oct 03, 2013
Flowering plants evolved from extinct plants related
to conifers, ginkgos, cycads, and seed ferns. The oldest known fossils from
flowering plants are pollen grains. These are small, robust and numerous and
therefore fossilize more easily than leaves and flowers.
An uninterrupted sequence of fossilized pollen from
flowers begins in the Early Cretaceous, approximately 140 million years ago,
and it is generally assumed that flowering plants first evolved around that
time.
But the present study documents flowering plant-like
pollen that is 100 million years older, implying that flowering plants may have
originated in the Early Triassic (between 252 to 247 million years ago) or even earlier.
Many studies have tried to estimate the age of
flowering plants from molecular data, but so far no consensus has been reached.
Depending on dataset and method, these estimates range from the Triassic to the
Cretaceous.
Molecular estimates typically need to be
"anchored" in fossil evidence, but extremely old fossils were not
available for flowering plants. "That is why the present finding of
flower-like pollen from the Triassic is significant", says Prof. Peter
Hochuli, University of Zurich.
Peter Hochuli and Susanne Feist-Burkhardt from
Paleontological Institute and Museum, University of Zurich, studied two
drilling cores from Weiach and Leuggern, northern Switzerland, and found pollen
grains that resemble fossil pollen from the earliest known flowering plants.
With Confocal Laser Scanning Microscopy, they obtained high-resolution images
across three dimensions of six different types of pollen.
In a previous study from 2004, Hochuli and
Feist-Burkhardt documented different, but clearly related flowering-plant-like
pollen from the Middle Triassic in cores from the Barents Sea, south of
Spitsbergen.
The samples from the present study were found 3000
km south of the previous site. "We believe that even highly cautious
scientists will now be convinced that flowering plants evolved long before the
Cretaceous", say Hochuli.
What might these primitive flowering plants have
looked like? In the Middle Triassic, both the Barents Sea and Switzerland lay
in the subtropics, but the area of Switzerland was much drier than the region
of the Barents Sea.
This implies that these plants occurred a broad
ecological range. The pollen's structure suggests that the plants were
pollinated by insects: most likely beetles, as bees would not evolve for
another 100 million years.
Peter A. Hochuli and Susanne Feist-Burkhardt.
Angiosperm-like pollen and Afropollis from the Middle Triassic (Anisian) of the
Germanic Basin (Northern Switzerland). Journal: Frontiers in Plant Science.
DOI: 10.3389/fpls.2013.00344
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