A small beetle buried in amber 99 million years ago reveals the displacement of continents

A tiny beetle trapped in amber for 99 million years reveals that Myanmar has already been one with South America.

The rare discovery, a new species called Propiestus archaicus, is an ancestor of beetles living in trash, which is found today only in South America and southern Arizona. The discovery of this anthropod ancestor from the Cretaceous period in Myanmar (formerly Burma) helps to clarify when and how the continents passed from two huge land masses to the seven continents we know today. [Image Gallery: Tiny Insect Pollinators Trapped in Amber]

"Although Propiestus long gone, our discovery probably shows amazing links between [the] Southern Hemisphere and Myanmar, "the lead author of the study, Shuhei Yamamoto, a researcher at the Chicago Field Museum, said in a statement.

Little treasure

Yamamoto managed to extract the beetle fossil from a piece of amber the size of a penny found in the Hukawng Valley, in northern Myanmar. Amber is a hardened upper Cretaceous tree sap, which was dirty and opaque from the ages accumulated by dirt and organic matter. Yamamoto used delicate tools and sandpaper to cut and polish the amber just enough for the beetle to be visible.

The insect is only 3 millimeters long, about the length of a ballpoint pen. He is black, with segmented blurry antennae that are almost as long as his body. These antennas were probably very sensitive to help the beetle make its way around its habitat, the narrow space under the bark of decaying trees.

"There would not have been much space available in the beetle habitat, so it was important to be able to detect everything," Yamamoto said.

Modern parents

Today, bark beetles are a large group, with more than 63,650 species present worldwide. The subfamily who P. archaius belongs to, Piestus, is now exclusively a southern hemisphere phenomenon, with the exception of a species found in southern Arizona, researchers said today (October 30) in the Journal of Systematic Palaeontology. This is the first time that a member of the subfamily has been found in Burmese amber, the researchers wrote, although two related fossils have been found in rocks of northeastern India. is from China.

Along with other insect fossils found in Burma's amber, the all-new Beetle suggests that Myanmar was once part of Gondwanaland, a sprawling megacontinent that formed after the dissolution of Pangea. It is made up of a large part of the landmass that makes up the continents of the southern hemisphere. In the Cretaceous, Gondwana and the United Kingdom separated to form more recognizable land masses like the continents of today. Tracing the location of today's species and their fossil ancestors can help determine when these divisions occurred. Although DNA evidence is needed to properly identify Piestus"Historical journeys," wrote the researchers, "it seems possible that the group is from Gondwana.

"Our conclusion is consistent with the assumption that, unlike what is happening today, Myanmar was once located in the southern hemisphere," Yamamoto said.

Originally published on Science live.