A newly discovered plant, a newly discovered wasp and a developing fly larva were found trapped in amber, in a delightfully preserved moment of prehistoric ecology.
If the image of an insect trapped in amber sounds familiar, you have George Poinar, Jr. to thank – the entomologist who made this discovery. His early work extracting insect DNA from Dominican amber directly inspired the premise of jurassic park.
His latest study documents the first fossil record of the plant genus Plukenetiaand the first record of the plant genus from the Caribbean island of Hispaniola.
“Fossil flowers of members of this family are quite rare,” Poinar said. “I was only able to find one previously known fossil, from sedimentary deposits in Tennessee.”
The famous Dominican amber is a fossilized form of resin from extinction Hymenaea protera tree, which scientists believe once grew in a tropical rainforest ecosystem, due to the variety of life forms that its resin buried.
This particular specimen was mined from the Cordillera Septentrional mountain range.
There is debate over the age of Dominican amber fossils, with conflicting theories based on the microorganisms used to date the specimens.
Some say the presence of foraminifera – single-celled protists sometimes called “armored amoebae” – indicates that amber formed around 20 to 15 million years ago.
Others suggest a date of 45 to 30 million years ago, based on the presence of coccoliths – calcium carbonate plates formed by single-celled phytoplankton called coccolithophores.
Poinar notes that it is further complicated because the amber was agitated and redeposited in turbulent sediments which then solidified into rock. Additionally, similar amber specimens found in Puerto Rico and Jamaica are dated to the Oligocene (33.9–23 million years ago) and Maastrichtian-Paleocene (72.1–66 million years ago). million years), respectively.
He estimates that this specimen is 30 million years old.
The fossil not only reveals a new plant species, but also an entire ecological microcosm, which Poinar says could include pollination, predation and even parasitism.
Modern members of the Euphorbia genus (the living relatives of the fossilized plant) are indeed pollinated by small wasps, so it is possible that this wasp played a similar ecological role.
The Fossilized Wasp – Hambletonia dominicanadiscovered and named by Poinar in 2020 – is an encyrtide wasp, a group of parasites known to lay their offspring with the eggs or larvae of smaller insects, which become a meal for young developing wasps.
Using high-resolution imagery, Poinar noticed a tiny gall midge (Cecidomyiidae) larva in one of the flower’s developing seeds and damage to the ovarian capsule that the midge inhabits.
He thinks that the wasp could have been attracted to the infected flower to lay an egg which, after hatching, would have quickly parasitized the gall midge larva.
Of course, the Wasp’s devious plot was cut short when a blob of sticky resin abruptly froze the three organisms into the array they’ve been stuck in for millions of years.
Poinar was so fascinated by the beauty of this fossilized moment that he compared its appearance to 20th-century art movements, with the flower’s “elegant curves” and “long lines” reminding him of Art Nouveau styles, and the “dance” of the wasp “decorative” shapes and “sharp angles” evoking Art Deco design.
“Depending on interests, background and current environment, everyone has their own way of interpreting visual images in the natural world,” Poinar said.
“An organism can be described, given a scientific name, and then stored in a taxonomic hierarchy.”
Fossil studies often focus on individual organisms and their place in the timeline of the tree of life, perhaps because it is rare to come across complete specimens, let alone such a clear indication of the multi-species interaction.
“In many cases, unrelated organisms are buried together in amber just by chance,” Poinar said.
“But I have the impression that in this case the wasp was attracted to the flower, either to obtain nectar or to try to lay an egg on the capsule which contains the fly larva.”
The paper was published in historical biology.