Researchers from St Petersburg University have made an exciting discovery in the Kaliningrad Amber Museum’s collection. They found an ancient ant belonging to the genus Manica trapped in a piece of amber. This particular species of ant, which had previously been found only in mountainous regions of Europe, the Caucasus, North America, and Japan, is estimated to be between 33.9 and 37.8 million years old. This finding marks the oldest and first-known fossil species of the Manica genus.
The scientists published their research findings in the journal Insects. Manica ants are typically around 5 to 6 millimeters long, and prior to this study, only six recent species of this genus had been identified. Four of these species inhabit the western part of North America, one is found in Japan, and another resides in the mountains of Europe and the Caucasus. The discovery of a new member of the Manica genus in Baltic amber found in Kaliningrad is significant, as these ants had not been observed in this region before.
Dmitry Zharkov, a young scientist from St Petersburg University’s Department of Applied Ecology and the first contributor to the study, noted that the species they described, Manica andrannae, is likely the ancestor of some modern ants from the Myrmicinae subfamily. This finding represents the first ancient specimen of the Manica genus in the fossilized state and the first of its kind in Europe.
Based on their research, the scientists propose that the Manica genus originated in North America. During the Eocene epoch, which spanned from 56 to 33.9 million years ago, land corridors connected North America to Eurasia through Beringia in the west and with Europe through the Thulean Bridge in the east. It is believed that one ancestral species migrated from America to Asia via Beringia, eventually giving rise to the modern species Manica yessensis, which is found in the mountains of Japan.
Other ancestors of the Manica genus migrated eastward and reached Europe during the early Eocene through the Thulean North Atlantic Bridge. It was in Europe that the scientists discovered Manica andrannae, the newly identified fossil species mentioned earlier.
The research was conducted using the resources available at St Petersburg University Research Park, particularly the Center for Microscopy and Microanalysis and the Center for X-Ray Diffraction Studies.
The hypothesis proposed by the St Petersburg University experts is supported by numerous studies that have shown the development of separate faunas in Europe and Asia during the Eocene period. The Tethys Sea, which separated Europe and Asia at the time, is believed to have acted as an insurmountable barrier to animal dispersal.
In addition, previous discoveries of fossilized insects in Baltic amber have demonstrated similarities to insect species found in the New World today. For instance, in 2022, St Petersburg University biologists identified and described another new fossil ant species from the Eocene period, named Dolichoderus jonasi, which shares similarities with species found in South and Central America.
The scientists were able to classify the newly discovered Manica andrannae specimen by conducting a detailed analysis of its morphological features. They employed computed microtomography, an advanced method that allowed them to digitize the ant and create a 3D model. This approach enabled a comprehensive study of all the fossil’s characteristics while disregarding other elements present in the amber, such as plant remains and air bubbles, which could have interfered with the analysis.
Source: St. Petersburg State University