According to the researchers, this is also the first time that fossils have been found in amber inclusions on the African continent.
An international team of researchers recently got their hands on a small paleontological treasure in Ethiopia; they unearthed samples of amber (a fossil resin) which contained 13 specimens of ants with strange morphology.
Thanks to the presence of pollen grains in the amber, they were able to proceed to an indirect dating of these insects; they were able to determine that they were between 16 and 23 million years old. However, their identity has been more difficult to confirm.
After initial analysis, it turned out that the ants in question did not correspond to any known species. At first, the researchers believed that these individuals belonged to the Aneuretinae subfamily. It is a particularly rare and almost extinct group; the vast majority of its representatives are now extinct and documented only in fossil form. As far as the researchers know, there is only one species, and it lives in Sri Lanka — a long way from where this sample was collected.
A whole new species of ant
So they pulled out the heavy guns by subjecting these ants to extensive examinations, based on state-of-the-art techniques. Indeed, it is impossible to carry out genetic analyses; this would require opening the amber case, which would compromise the integrity of these very old samples. The only solution is therefore to study them from the outside as precisely as possible.
In particular, they used X-ray tomography. This is a technique whose different variants are used in many fields such as geology, materials science or medicine (we then speak of computed tomography). This consists of measuring the absorption of X-rays from different tissues to produce a sort of 3D anatomical map.
But conventional CT scans are too inaccurate to work in this case; they therefore had to resort to synchrotron microtomography. It is an extremely precise variation of this technique that has enabled them to produce images in very high resolution.
And the details they spotted there ruled out the trail of Aneuretinae; rather, they pointed to a radically different subfamily. The shape of the abdomen and mandibles, in particular, were closer to those found in Ponerinae ants.
They therefore assigned a new species and a new taxonomic genus to this now extinct subfamily. They named her Desyopone hereon, in honor of DESY and Hereon — two of the institutions that contributed greatly to this work. For the record, the DESY is a prestigious laboratory whose particle accelerator distinguished itself last summer by “smelling” the concert of a famous metal band (see our article).
A window on the Africa of yesteryear
The other element that makes this discovery very interesting is that until now, specialists had not yet found any piece of amber with fossil inclusions in Africa. Indeed, amber is traditionally used by local people to make jewelry. According to the researchers, this is the very first time that an amber inclusion containing fossils of living beings has been found in Africa.
” Its scientific importance has only become clear to researchers over the past decade. explains Vincent Perrichot, a researcher from the University of Rennes who took part in this work. ” Overall, there are very few insect fossils from this continent “, he specifies. This sample therefore offers a unique perspective on an ancient African forest ecosystem » ; all that remains is to unearth new pieces of amber full of treasures to learn more about this abundant ecological niche.
The text of the study is available here.