Researchers at Oregon State University have described a new legume tree from flowers embedded in several pieces of amber salvaged from deep within an amber mine in the mountains of the Dominican Republic.
George Poinar Jr. and Kenton Chambers of OSU placed the 20-30 million year old flowers in a new genus and species, Salpinganthium hispaniolanum, in the family Fabaceae.
“The flowers are quite striking with their spreading sepals and petals, as well as the 10 extended stamens,” said Poinar, an international expert in the use of plant and animal life forms preserved in amber to learn more about the biology and ecology of the distant past. “While now darkened with age, the petals were probably white, yellow or even pink, which are the colors of the petals of the closely related purple-hearted tree, whose strong, durable, purplish wood is prized by artists, shipbuilders, furniture makers and other trades people.”
Groves of purple-hearted trees continue to grow along rivers in the tropical rainforests of Central and South America, particularly in the Amazon Basin, said Poinar, a professor emeritus at the Oregon State College of Science.
Poinar and Chambers, a professor emeritus at OSU’s College of Agricultural Sciences, derived the genus name from the Greek words for tube, trumpet, and flower. The species name is based on the Caribbean island, Hispaniola, where the fossil originated.
“While the purple-hearted trees are still among us, the Salpinganthium trees have disappeared,” Poinar said. “We can only speculate why these fossil trees disappeared.”
They might have succumbed to some unique biological and/or physical event, such as the loss of a pollinator, the presence of a pathogen, or a climate change that has ravaged populations across their range, Poinar said. Finding their flowers in five separate pieces of amber shows that they were well established in the Dominican amber forest, he added.
Poinar and Chambers placed Salpinganthium hispaniolanum, the last of a number of flowers described by authors from the Dominican amber mines, in the resin-producing tribe Detarieae; members of the tribe have sepals and petals studded with glands.
“Another member of this tribe, Hymenaea, produced the resin that became the world famous Dominican amber,” Poinar said.
The study was published in the Journal of the Botanical Research Institute of Texas.