Scientists from St Petersburg University discover a new fossil species of caddisflies
Entomologists from St Petersburg University, together with their colleagues from the Borissiak Palaeontological Institute of the Russian Academy of Sciences, Cherepovets State University and the Natural History Museum of Denmark, have discovered a new fossil species of caddisflies in Eocene Rovno amber. It was named Electroadicella unipetra to mark the 300th anniversary of St Petersburg University: the species name, unipetra, was derived from the Latin name of this university.
Insects found in amber provide important evidence of the evolution of living nature. Even many years later, they enable scientists to establish relationships between modern species. Additionally, the study of fossil insects makes it possible to reconstruct the habitats of animals from past eras and the climatic changes that have taken place on our planet.
The research findings are published in the scientific journal Ecologica Montenegrina.
The scientists from St Petersburg University, together with their colleagues from other scientific organisations, have discovered a new species of caddisflies in Rovno amber. Caddisflies are insects with a complete metamorphosis and are the closest relatives of lepidopterans (butterflies and moths). The team of the Department of Entomology at St Petersburg University has been conducting continuous and extensive research on these insects for more than 40 years.
Today, science knows 262 species of caddisflies from the Palaeogene resins of Europe and 38 species of representatives of this group from Rovno amber. The new species Electroadicella unipetra discovered by the scientists from St Petersburg University belongs to the order Trichoptera, suborder Integripalpia, family Leptoceridae, genus Electroadicella. This genus is also found in Baltic and Saxon Eocene amber. However, this is the first time it has been found in Rovno amber. This finding indicates a wide distribution of the genus Electroadicella on the territory of Eastern and Central Europe in the Upper Eocene (about 35 million years ago).
The fossil insect was found in a piece of amber weighing 13.3 grams. The holotype of Electroadicella unipetra described by the University scientists has a body length of 5.2 mm and a front wing length of 6.5 mm. The overall colouration is yellowish-brown, with long dark brown hairs on the wings. As noted by the entomologists from St Petersburg University, the species discovered is sufficiently well preserved. This has allowed the morphology of the genital structures, widely used in the taxonomy of this group of insects, to be studied and described in detail using microscopic research methods.
Vladimir Ivanov, a co-author of the study, Associate Professor of St Petersburg University, Candidate of Biology, said that the species found belongs to the family of long-horned caddisflies (Leptoceridae), which in modern nature is most often found in tropical latitudes.
"This find indicates the warm climate of the Rovno deposit, located in what is now north-western Ukraine. The Rovno fossil resins are close in origin to Baltic amber, but were formed further south, on a large island in a warm sea. They have a slightly different fauna, which differs from the well-studied fauna of Baltic amber," said Vladimir Ivanov.
Research on caddisflies from Rovno amber began at the Department of Entomology at St Petersburg University about 15 years ago. So far, 28 new species of caddisflies from eight families have been described. Ten other species have also been found in Baltic amber.
The caddisflies, or order Trichoptera, contains more than 17,500 species of insects, including about 400 fossils. The family from which the new species is described contains about 2,100 modern species and only 23 fossils. This includes the oldest member of this family, Protorodinia khasurtensis, recently described by entomologists from St Petersburg University, which lived about 125-145 million years ago and was found in Lower Cretaceous sediments of the Republic of Buryatia.
"In modern nature, insects of this family are usually abundant in many ecosystems, in contrast to amber faunas, the material from which testifies to the low abundance of these insects in amber-bearing forests of the Eocene of Europe. The general appearance of the caddisfly fauna from the Palaeogene amber of Europe differs from the modern one in a number of parameters. The formation of the modern boreal European caddisfly fauna was influenced by changes in climate, land configuration and mountain formation in subsequent epochs," explained Stanislav Melnitsky, a co-author of the study, Associate Professor at St Petersburg University, Candidate of Biology.
According to the entomologists from St Petersburg University, the warmer and probably drier climate of Rovno in comparison with the Baltic amber-bearing forest, and the geographical features of this area in the Late Eocene, may lead to the fact that more than 80% of the species of caddisflies from Rovno amber are endemic or the northern limit of their range was restricted to this geographical area in the Late Eocene.
St Petersburg University, the oldest university in Russia, was founded on 28 January (8 February) 1724. This is the day when Peter the Great issued a decree establishing the University and the Russian Academy of Sciences. Today, St Petersburg University is an internationally recognised centre for education, research and culture. In 2024, St Petersburg University celebrates its 300th anniversary.
The plan of events during the celebration of the anniversary of the University was approved at the meeting of the Organising Committee for the celebration of St Petersburg University’s 300th anniversary. The meeting was chaired by Dmitry Chernyshenko, Deputy Prime Minister of the Russian Federation. Among the events are: the naming of a minor planet in honour of St Petersburg University; the issuance of bank cards with a special design; and the branding of the aircraft of the Rossiya Airlines to name just a few. To mark the 300th anniversary of St Petersburg University, a postage stamp depicting the Twelve Collegia building and the monument to Count Sergey Uvarov was issued.
By the decision of the Governor of St Petersburg Alexander Beglov, 2024 is a year of the 300th anniversary of St Petersburg University in St Petersburg. On the day of the University’s 300th anniversary torches will be lit on the Rostral Columns on the Spit of Vasilyevsky Island. St Petersburg University flags will be raised on the Palace Bridge. The city public transport will be decorated with the University’s symbols. New tourist maps will feature the locations of the University buildings, with thematic and historical materials about the University placed nearby. During St Petersburg’s City Day celebrations in May 2024, St Petersburg University will be a participating venue. The traditional "Scarlet Sails Festival" will also be dedicated to the anniversaries of St Petersburg University and the Russian Academy of Sciences. Additionally, the University has launched a website dedicated to the upcoming holiday. The website contains information about outstanding University staff, students, and alumni; scientific achievements; and details of preparations for the anniversary.