A revision of Silurian corals (Anthozoa: Heliolitoidea) from the collection of the National Museum of Natural History, NAS of Ukraine (Kyiv)

he collection of Silurian heliolitoid corals revised in this study has been assembled by the first author (V.G.) for four decades. The material was collected predominantly from Silurian outcrops and borehole cores in the Middle Dnister area. Some of the specimens were found in Belarus and Moldova during field works and field trips. The scientific works were part of the projects elaborated by a collective of scientists from the Institute of Geological Sciences, NAS of Ukraine and Taras Shevchenko National University of Kyiv. The working group consisted of geologists who graduated from the university in 1965 to 1970. Professors M. M. Klushnikov and O. L. Einor were our advisors. P. D. Tsegelnjuk was the oldest and the leader of the group. The collecting of specimens started in 1966 and now is ready to summarise the results. In the last fifty years, a large collection of fossil cnidarians from Silurian deposits has been assembled in the course of long-term geological field expeditions organised to study outcrops, cores of boreholes, and collect fossils. More than fifty outcrops and one hundred boreholes were studied in the territory of the Podillian region and the west slope of the Ukrainian Shield from Volyn to Snake Island. The collection comprises nearly ten thousand samples and 6000 thin sections of cnidarians. The total number of the studied samples belonging to Heliolitoidea is 139, of which 19 came from 9 outcrops and 120 from cores of 37 boreholes. The described samples represent 3 orders, 1 superfamily, 8 families, 2 subfamilies, 16 genera, 20 species (11 new), and 1 new subspecies. The authors consider that all the remains belong to fossil cnidarians. Fossil cnidarians are especially important from a facial point of view. The remains primarily indicate normal sea conditions in warm subtropical and tropical zones. In some cases, the identification of fossil cnidarians is easy, but usually we need to use the oriented thin sections. In the paper, only a small part of the collection is described following the system of Heliolitoidea developed by Olga Bondarenko. A studied collection is deposited in the Geological Department of the National Museum of Natural History, NAS of Ukraine under the number GD-1986.