A 99 – million – year – old fossil flower found enclosed in Burmese amber Paleontology

A team of paleontologists from Oregon State University and the U.S. Department of Agriculture’s Department of Agricultural Research found a new genus and species of fossil angiosperms in amber deposits of middle Cretaceous amber in Myanmar.

Valviloculus pleristaminis, a flower in lateral view. Image credit: Poinar, Jr. and others., doi: 10.17348 / jbrit.v14.i2.1014.

A new fossil flower, named Valviloculus pleristaminis, belongs to the order Laurales, whose closest affinities are with the families Monimiaceae and Atherospermataceae.

“This isn’t exactly a Christmas flower, but it’s a beauty, especially since 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 at Oregon State University. .

“The male flower is tiny, about 2 mm in diameter, but has about 50 anthers arranged like a spiral, with anthers pointing towards the sky.”

“The stamen consists of anthers (the head that produces pollen) and threads (the stem that connects the anthers to the flower).”

“Even though we’re so small, the details that still remain are amazing.”

“Our specimen was probably part of a cluster of plants that contained many similar flowers, some of which may be female.”

Valviloculus pleristaminis, the center of the flower at the apex.  Credit for the painting: Poinar, Jr., etc., Doi: 10.17348 / jbrit.v14.i2.1014.

Valviloculus pleristaminis, the center of the flower at the apex. Image credit: Poinar, Jr. and others., doi: 10.17348 / jbrit.v14.i2.1014.

A copy Valviloculus pleristaminis has a hollow flower cup in the shape of an egg (the part of the flower from which the anthers originate); an outer layer consisting of six petal-like components known as tepals; and two-chamber anthers, with pollen sacs opening through lateral articulated valves.

It is packaged in amber on the supercontinent of Gondwana and is floated on a continental plate about 6,450 km (4,000 miles) across the ocean from Australia to Southeast Asia.

Geologists debated just when this piece of land – known as the West Burmese bloc – separated from Gondwana.

Some scientists believe it was 200 million years ago; others claim that it was 500 million years ago.

“Since the angiosperms only evolved and separated approximately 100 million years ago, the West Burmese bloc could not have been separated from Gondwana before, which is much later than the date proposed by geologists,” said Professor Poinar.

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

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GO Poinar, Jr. and others. 2020 Valviloculus pleristaminis gen. et sp. nov., a fossil Loralea flower with valvatic anthers from Middle Cretaceous amber from Myanmar. Journal of the Texas Botanical Research Institute 14 (2): 359-366; doi: 10.17348 / jbrit.v14.i2.1014

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