99 million year old fossil flower found encased in Burmese amber | Paleontology

A team of paleontologists from Oregon State University and the Agricultural Research Service of the U.S. Department of Agriculture have found a new genus and species of fossil angiosperm in the middle chalky amber deposits in Myanmar.

Valviloculus pleristaminis, flower in side view.  Image Credit: Poinar, Jr.  et al., doi: 10.17348 / jbrit.v14.i2.1014.

Valviloculus pleristaminis, flower in side view. Image Credit: Poinar, Jr. et al., doi: 10.17348 / jbrit.v14.i2.1014.

The new fossil flower, named Valviloculus pleristaminisbelongs to the order Laurales, whose closest connection is to the families Monimiaceae and Atherospermataceae.

“This is not quite a Christmas flower, but it is a beauty, especially considering that it was part of a forest that existed almost 100 million years ago,” said lead author Professor George Poinar Jr., a paleontologist at the Department of Integrative Biology at Oregon State University.

“The male flower is small, approx. 2 mm wide, but it has about 50 stamens arranged like a spiral, with rods pointing towards the sky. ”

“A stamen consists of a shovel (pollen-producing head) and a filament (stem that connects the founder to the flower).”

“Despite being so small, the remaining detail is astounding.”

“Our sample was probably part of a cluster on the plant that contained many similar flowers, some possibly female.”

Valviloculus pleristaminis, center of flowers in apical view.  Image Credit: Poinar, Jr.  et al., doi: 10.17348 / jbrit.v14.i2.1014.

Valviloculus pleristaminis, flower center in apical view. Image Credit: Poinar, Jr. et al., doi: 10.17348 / jbrit.v14.i2.1014.

The sample of Valviloculus pleristaminis has an ovate, hollow flower cup (part of the flower from which the stamens originate) has an outer layer consisting of six petal-like components known as tepals; and two-chamber pins, with pollen sacs opened via laterally hinged valves.

It was encapsulated amber on the supercontinent Gondwana and rafted on a continental plate about 6,450 km above sea level from Australia to Southeast Asia.

Geologists have been debating just when this piece of land – known as the West Burma Block – broke loose from Gondwana.

Some scientists believe it was 200 million years ago; others claim it looked more than 500 million years ago.

“Since angiosperms only evolved and diversified about 100 million years ago, the West Burma Block could not have broken away from Gondwana until then, which is much later than dates suggested by geologists,” said Professor Poinar.

The discovery is described in a paper in Journal of the Botanical Research Institute of Texas.

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GO Poinar, Jr. et al. 2020. Valviloculus pleristaminis gen. et sp. nov., a Lauralean fossil flower with valvate anthers from the center of chalk Myanmar amber. Journal of the Botanical Research Institute of Texas 14 (2): 359-366; doi: 10.17348 / jbrit.v14.i2.1014

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