A team of paleontologists from Oregon State University and the Agricultural Research Service of the United States Department of Agriculture has found a new genus and species of fossil angiosperm in the mid-Cretaceous amber of Myanmar.
Valviloculus pleristaminis, flower in side view. Image credit: Poinar, Jr. et al., doi: 10.17348 / jbrit.v14.i2.1014.
The new fossil flower, called Valviloculus pleristaminis, belongs to the order Laurales, which is most closely related to the families Monimiaceae and Atherospermataceae.
“This isn’t quite a Christmas flower, but it is a beauty, especially considering that it was part of a forest that existed nearly 100 million years ago,” said lead author Professor George Poinar Jr., a paleontologist in the Department of Integrative Biology. from Oregon State University.
“The male flower is small, about 2mm wide, but has about 50 stamens arranged spirally, with anthers pointing towards the sky.”
“A stamen consists of an anther (pollen producing head) and a filament (stem that connects the anther to the flower).”
“Despite being so small, the details are still amazing.”
“Our specimen was probably part of a cluster on the plant that contained many similar flowers, some possibly female.”
Valviloculus pleristaminis, center of flower in apical view. Image credit: Poinar, Jr. et al., doi: 10.17348 / jbrit.v14.i2.1014.
The copy of Valviloculus pleristaminis has an egg-shaped, hollow flower cup (part of the flower from which the stamens emerge); an outer layer consisting of six petal-like components known as tepals; and bicameral anthers, with pollen sacs that split open via laterally hinged flaps.
It was sheathed in amber on the supercontinent of Gondwana and rafted on a continental plate some 6,450 km (4,000 miles) across the ocean from Australia to Southeast Asia.
Geologists have debated just as this stretch of land – known as the West Burma Block – was breaking away from Gondwana.
Some scientists think it was 200 million years ago; others claim it was more than 500 million years ago.
“Since angiosperms only evolved and diversified about 100 million years ago, the Western Burma block could not have broken off from Gondwana sooner, which is much later than the dates suggested by geologists,” said Professor Poinar.
The discovery is described in an article in the Journal of the Botanical Research Institute of Texas.
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GO Poinar, Jr. et al. 2020. Valviloculus pleristaminis gene. et sp. nov., a Lauralean fossil flower with valvate anthers from the mid-Cretaceous Myanmar amber. Journal of the Botanical Research Institute of Texas 14 (2): 359-366; doi: 10.17348 / jbrit.v14.i2.1014