Revision of the type series of selected endemic mollusc species from the Lower Oligocene deposits of the Crimea (Ukraine)

[Андрейчак, В., Березовський, А. Ревізія типових серій деяких ендемічних видів молюсків із нижньоолігоценових відкладів Криму (Україна)]

Viktoria Andreichak,https://orcid.org/0000-0002-3272-2150

Anatoly Berezovsky,https://orcid.org/0000-0003-0490-769X

Kryvyi Rih National University, (Kryvyi Rih, Ukraine)

Cite as

Andreichak, V., & Berezovsky, A. (2026). Revision of the type series of selected endemic mollusc species from the Lower Oligocene deposits of the Crimea (Ukraine). GEO&BIO, 28, 39-48.

doi: https://doi.org/10.53452/gb2805

pdf: G&B №28-2026_39-48_Andreichak.pdf

Abstract

This article aims to clarify data concerning the lectotypes of several mollusc species described by V. G. Kulichenko in 1963 and 1969 from the Lower Oligocene clay deposits near the village of Zubakino (Crimea), namely Venericardium korobkovi, Murex crimensis, and Pleurotoma almaensis. For the first time, the authors report the previously unpublished repository of these lectotypes and provide their measurements, which were lacking in the original descriptions. The lectotype specimens have been re-photographed, allowing previously unrecognised morphological features to be documented. A detailed re-description of the shells is presented, expanding the range of diagnostic characters, identifying features that were previously overlooked, and correcting inaccuracies in the original accounts. The generic assignments of the gastropod taxa have been updated in accordance with modern taxonomy: Pleurotoma almaensis is reassigned to Gemmula almaensis, and Murex crimensis to Beyregrex crimensis. The species Venericardium korobkovi is characterised by small, triangular-rounded, moderately convex valves. The external surface bears 14–15 widely spaced radial ribs and fine, closely spaced concentric striations. Each radial rib possesses a low, triangular base, with each flank bearing a secondary fine radial rib, and a narrow, rounded crest ornamented with subdued tubercles. The hinge of the right valve comprises the cardinal tooth 3b and two lateral teeth (AI and PIII), whereas the left valve contains two cardinal teeth (2 and 4b) and two lateral teeth (AII and PII). In Gemmula almaensis, the shell is of medium size and comprises four whorls. The spire is moderately high, and the final whorl is relatively large. The whorls are angular in profile, with the first three being smooth. Axial and spiral ornamentation develops progressively on the fourth whorl, forming tubercles at the intersections of axial and spiral elements. The body whorl bears nine transverse ribs. The aperture is large and oval, with a very narrow and elongated siphonal canal. The outer lip is broad and has a serrated margin. In Beyregrex crimensis, the shell is of medium size and consists of eight rounded, convex whorls forming a high spire. The whorl surface displays both axial and spiral sculpture, with axial ribs confined to the upper portion of the whorls. The aperture is elongate and pear-shaped, with a long and narrow siphonal canal.

Key words

molluscs, shell morphology, taxonomy, Palaeogene, Ukraine

Correspondence to: Anatoly Berezovsky; Kryvyi Rih National University, 11 Vitaliya Matusevycha Street, Kryvyi Rih 50027, Ukraine; e-mail: berez@knu.edu.ua

Article info

Submitted: 29.04.2026. Revised: 18.05.2026. Accepted: 25.05.2026

References

Amitrov, O. V. (1973). Late Eocene–Early Miocene turrids of the southern USSR. Transactions of the Palaeontological Institute, 135, 1–190. [Russian]

Berezovsky, A. A. (2010). Bivalves of the Middle and Upper Eocene of the Ukrainian Platform: Taxonomic Revision, Evolution, Palaeogeography and Palaeoecology. Thesis for the degree of Doctor of Geological Sciences in the speciality 04.00.09 – Palaeontology and Stratigraphy [Manuscript]. In 7 volumes. Vol. 4. Kryvyi Rih. [Russian]

Cox, L. R., Newell, N. D., Boyd, D. W., Branson, C. C., Casey, R., Chavan, A., Coogan, A. H., Deshaseaux, C., Fleming, C. A., Haas, F., Hertlein, L. G. [et al.] (1969). Mollusca 6. Bivalvia. In: Moore, R. C. (Ed.), Treatise on Invertebrate Paleontology. The Geological Society of America and the University of Kansas, 1–951. Kansas.

von Koenen, A. (1890). Das norddeutsche Unter-Oligocän und seine Mollusken-Fauna. Abhandlungen zur Geologischen Specialkarte von Preussen und den Thüringischen Staaten, 2, 281–574.

Kulichenko, V. G. (1963a). Finds of fossil gastropods of the family Muricidae in the Khadumian Horizon of western Crimea. Reports of the Academy of Sciences of the Ukrainian SSR, 1, 98–100. [Ukrainian]

Kulichenko, V. G. (1963b). A new fossil gastropods of the family Pleurotomidae from the Khadumian Horizon of the western Crimea. Reports of the Academy of Sciences of the Ukrainian SSR, 3, 398–400. [Ukrainian]

Kulichenko, V. G. (1968a). Oligocene bivalves of the south-western Crimea. Paleontological Review, 5(2), 31–37. [Russian]

Kulichenko, V. G. (1968b). On the palaeontological characterisation of the Crimean Palaeogene stratotype. Geological Journal, 28(5), 54–61. [Russian]

Marquet, R., Lenaerts, J., & Laporte, J. (2012). A systematic study of the Bivalvia (Mollusca) from the Grimmertingen sand member and from the Klimmen member (Early Oligocene) in Belgium and the Netherlands. Palaeontos, 22, 1–151.

Merklin, R. L. (1974). Guide to Oligocene bivalves of the USSR. Transactions of the Palaeontological Institute, 145, 1–190. [Russian]

Merle, D., Pacaud, J.-M., Ledon, D., & Goret, B. (2024). New Cenozoic Muricidae (Mollusca: Gastropoda) from Europe. Geodiversitas, 46, 495–551. https://doi.org/10.5252/geodiversitas2024v46a15