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A team of paleontologists from Oregon State University and the Agricultural Research Service of the United States Department of Agriculture have discovered a new genus and species of fossil angiosperms in amber deposits in the middle of the Cretaceous in Myanmar.
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 pleristaminis, belongs to the order Laurales, its closest affinities being with the families Monimiaceae and Atherospermataceae.
“It’s not quite a Christmas flower but it is a beauty, especially since it was part of a forest that existed almost 100 million years ago,” said the lead author Professor George Poinar Jr., a paleontologist in the Department of Integrative Biology at Oregon State University.
“The male flower is tiny, about 2mm in diameter, but it has about 50 stamens arranged in a spiral, with anthers pointing skyward.
“A stamen consists of an anther (pollen-producing head) and a filament (stem that connects the anther to the flower).”
“Despite their small size, the details that remain are incredible.”
“Our specimen was probably part of a cluster on the plant that contained many similar flowers, some possibly female.
Valviloculus pleristaminis, flower center in apical view. Image Credit: Poinar, Jr. et al., doi: 10.17348 / jbrit.v14.i2.1014.
The specimen of Valviloculus pleristaminis has a hollow egg-shaped floral cup (part of the flower from which the stamens emanate); an outer layer made up of six petal-shaped components known as tepals; and two-chambered anthers, with pollen sacs that open by laterally articulated valves.
He locked himself in amber on the supercontinent of Gondwana and rafted a continental plate some 6,450 km (4,000 miles) across the ocean from Australia to South Asia -East.
Geologists debated just as this piece of land – known as the West Burma Block – broke away from Gondwana.
Some scientists believe it was 200 million years ago; others claim it was over 500 million years ago.
“Since angiosperms only evolved and diversified around 100 million years ago, the Western Burma bloc could not have separated from Gondwana before that date, which is much more later than the dates suggested by geologists, ”Professor Poinar said.
The discovery is described in an article in Journal of the Texas Botanical Research Institute.
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GO Poinar, Jr. et al. 2020. Valviloculus pleristaminis gen. and sp. nov., a Laurel fossil flower with valvate anthers from the mid-Cretaceous Myanmar amber Journal of the Texas Botanical Research Institute 14 (2): 359-366; doi: 10.17348 / jbrit.v14.i2.1014
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