Saturday, April 02, 2011

A Eudicot from the Early Cretaceous of China

A eudicot from the Early Cretaceous of China. 2011. D. Sun, et al. Nature 471: 625–628.

Scientists have discovered the first intact fossil of a mature eudicot, a type of flowering plant whose membership includes buttercups, apple trees, maple trees, dandelions and proteas.
The 125 million-year-old fossil was named Leefructus mirus in honor of Li Shiming, a non-scientist who donated the fossil to Ge Sun's new museum of paleontology in Liaoning Province, China.

The fossil shows the above-ground portion of a mature plant. A single stem leads to five leaves, and one leads to a fully developed flower. The entire fossil is about 16 cm (6.3 in) tall. Leaves are innervated by branching veins, and the small, cup-shaped flower has five petals.

"We are also beginning to understand that the explosive radiation of all flowering plants about 111 million years ago has had a long history that began with the slower diversification of many families of eudicots over 10, perhaps 15 million years earlier."

"I think Leefructus had attractive flowers to advertise for pollinators to visit," said Dilcher, when asked to speculate. "There were no bees at this time, so I think that flies, beetles or extinct types of moths or scorpion flies may have been involved in its pollination. Leefructus was found in the volcanic ash beds of an ancient lake. I think it was living near a lake, perhaps in a wet or marshy area much as buttercups do today."

The profusion of flowering plant species in the second half of the Mesozoic Era, the age of dinosaurs, eventually led to flowers' domination of other types of plants in all but Earth's harshest climates. Evolutionary biologists believe the diversification of flowering plants also supported the radiation of a wide range of animal species, particularly pollinators and seed eaters, from beetles and bees to hummingbirds and bats.

Until now, most fossil information about the earliest eudicots has come from fossilized pollen, the plant equivalent of sperm. Despite pollen's small size, pollen grains have provided crucial information to paleontologists. But pollen can only tell scientists so much. link