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М. Kovalchuk

Abstract

New Extinct Carp Fish Species (Teleostei, Cyprinidae) from the Late Neogene of Southeastern Europe. Kovalchuk, О. М. - A new extinct carp fish taxa from the Upper Neogene strata of Southeastern Europe are described in the paper. Rutilus robustus Kovalchuk, sp. n. from the Early Pliocene of Priozernoe (Republic of Moldova) differs from other species of the Rutilus genus by the massive high ceratobranchiale, long anterior non-dentiferous process, and also thick bulkheads between the septum on cavernous surface. Scardinius ponticus Kovalchuk, sp. n. from the Late Miocene of Odesa Pontian Lectostratotype (Ukraine) is characterized by the enormous pharyngeal teeth, and the enlarged number of cogs at their external grinding edge.

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О. М. Kovalchuk

Abstract

Bony Fishes from the Late Miocene and Pliocene Strata of Popovo Locality (Ukraine): Taxonomic Changes and Their Palaeoecological Explanation. Kovalchuk, О. М. - Th e present paper deals with results of studying of the fossil fish remnants from the Late Miocene and Pliocene strata of Popovo locality (Southern Ukraine). Our aim was to show local taxonomic changes in freshwater fish communities through-out the specified range of geological time. Twenty seven species of the 20 genera, 6 families (Cyprinidae, Cobitidae, Siluridae, Salmonidae, Esocidae, Percidae) and 5 orders (Cypriniformes, Siluriformes, Salmoniformes, Esociformes, Perciformes) were identified from the 4 heterochronous bonyferous layers. Basing on taxonomic richness, diversity, complexity and similarity of communities, it can be assumed, that changes in their qualitative and quantitative composition were caused by hydrological regime transformation, palaeogeographical alterations and also local taphonomic features.

Open access

О. М. Kovalchuk

Until now, fossil remains of Hucho Gunther, 1866 are known only from the Oligocene - middle Miocene strata of Baikal Russia, and from the late Pleistocene of Germany. New specimens, now identified as Hucho sp., come from the late Miocene of southern Ukraine. Numerous fragments of opercular bones and jaw teeth, morphologically similar to those in the extant genus Hucho, were found in Kubanka 2, Cherevychnoe 3, Tretya Krucha localities and dated by the late Sarmatian - early Maeotian (10-8 Ma). Th ese remains document the first appearance of huchen in geological past of Europe, filling in gap in distribution of this genus during the late Neogene, and throw light upon its biogeographical history.

Open access

О. М. Kovalchuk

Abstract

This paper presents analytical results of the study of numerous freshwater fish fossils from almost 40 localities in the territory of southeastern Europe. It has been established that freshwater fishes can be regarded as parastratigraphic group suitable for biostratigraphic studies. Ten ichthyofaunal assemblages have been distinguished and characterized in the paper. These assemblages represent successive developmental stages in freshwater fish communities within southeastern Europe during the late Miocene, Pliocene and Pleistocene. Indices of evolutionary transformations (extinction rate, origination rate, taxonomic rotation) for ichthyofaunal assemblages have been calculated, and their trend is discussed herein.

Open access

О. М. Kovalchuk, V. A. Marareskul, D. S. Zakharov and T. F. Obadă

Abstract

A fossil fish remnants from the Early Pliocene strata of the Dniester valley (Republic of Moldova) are described in the paper. Seven species, belonging to 6 genera, 4 families and 4 orders (Acipenseriformes, Cypriniformes, Siluriformes, Esociformes) were identified in Nikolskoe and Uyutnoe localities. All of them are analogues of extant taxa. A brief review of development of the freshwater fish fauna in the Lower Dniester Basin during the Early Pliocene is presented.