A team of paleontologists led by Assistant Vladimir Nikolov from the National Museum of Natural History, Sofia (NMNHS) described the first fossil remains of gars found in Bulgaria. The results of the study are published in the prestigious paleontological journal “Cretaceous Research” (Web of Science: 1st Quartile; Journal Impact Factor: 1.9).
The fossils were collected in the period 2020—2023 during field work at the fossil locality near the town of Tran, which is known for producing remains of non-avian dinosaurs. The age of the locality and the fossils discovered there is about 83 million years. The Bulgarian record of gars reveals novel information about the paleogeographic distribution of these fishes within the Late Cretaceous European Archipelago.
A link to the online version of the published study at the platform ScienceDirect, with freely accessible “Abstract” and “Introduction” sections can be found here: sciencedirect.com/science/article/pii/S0195667124001587.
Co-authors of the study are Dr Plamen Andreev (Research Center of Natural History and Culture, Qujing Normal University, China), Georgi Voykov (undergraduate student from Sofia University) and Assoc. Prof. Dr Docho Dochev (Sofia University).
The studied fossil material consists of nine teeth and three scales, collected from 2020 to 2023 during field work at the non-avian dinosaur fossil locality near the town of Tran. Eight of the gar teeth were found in sediment samples collected in 2021, which were later processed in the paleontological laboratory of NMNHS. Despite the fact that the fossils are too fragmentary, they preserve enough distinct morphological characteristics to allow for reliable taxonomic identification — the teeth are conical with longitudinal grooves and striations, while the scales are thick and covered with thin-layer of hypermineralised (enamel-like) tissue called ganoin, which is ornamented by numerous microscopic tubercules. Teeth and scales of this kind are typical for the predatory fish from the family Lepisosteidae — vernacularly known as gars.
The gar fossils found near Tran are among the few cases of gars discovered in Europe, which are older than 80 million years. They also mark the easternmost occurrence of these fishes within the European Archipelago. Furthermore, the Tran gars appear to be the first record of Mesozoic freshwater fish from Bulgaria.
The gars (Family Lepisosteidae) are a group of predatory ray-finned fishes, which in modern times are restricted to parts of southeastern North America, Central America, and Cuba. The family consists of a total of seven species, which are distributed in the genera Lepisosteus (with 4 species) and Atractosteus (with 3 species). In the geological past, especially during the Cretaceous Period, the gars were taxonomically much more diverse and enjoyed significantly wider geographic distribution — their fossils are found in North America, South America, Europe, the northern parts of Africa, Madagascar, and India.
There are about 28 fossil localities in Europe, which are known to yield fossil remains of these predatory fishes. Most of these localities are located in the western and central parts of Europe and the fossil-bearing rocks are about 72—66 million years old. An exception from this trend are few localities in Romania, however, it should be noted that towards the end of the Mesozoic Era these territories were located westward from their current position.
The oldest known gar — Nhanulepisosteus mexicanus — is found in Mexico and is about 150 million years old. The first representatives of the group of the extant gars seem to have appeared in the beginning of the Late Cretaceous Epoch, about 100 million years ago.
The modern-day gars are predominantly freshwater predators, but for some of the species there is empirical data that they occasionally enter brackish and even sea waters. It is generally accepted that the same applies to their Late Cretaceous relatives.
The study is funded by the Bulgarian National Science Fund of the Ministry of Education and Science (KP-06-N44/6). Field work in the period 2020—2022 is financially supported by the Jurassic Foundation, Karoll Knowledge Foundation, Murgana Geological Consulting Ltd, and United Bulgarian Bank.