title: On the Leptocytheridae Ostracods of the Long-Lived Lake Ohrid: A Reappraisal of their Taxonomic Assignment and Biogeographic Origin.
abstract: Leptocythere karamaniKlie, one of few non-marine species of the family Leptocytheridae (Ostracoda), is redescribed from specimens recently collected from the long-lived Lake Ohrid on the Albanian-Macedonian border. Detailed morphologies of valves and limbs of this species were compared with those of other Ohrid-Prespa leptocytherids, of some recent marine representatives of the generaLeptocythereSars andCallistocythereRuggieri from the Mediterranean, Irish and Baltic seas as well as with that of fossil non-marine species from the Miocene palaeo-Lake Pannon belonging to the generaAmnicythereDevoto andEuxinocythereStancheva. Comparison with other species of Leptocytheridae inhabiting fresh to brackish waters of the Black-Azov, Caspian and Aral seas were also carried out using descriptions provided in the literature. Based on the comparative morphological studies it is shown thatL. karamaniand other Ohrid leptocytherids have a number of characters distinguishing them from other members of the genusLeptocytherebut demonstrating a relationship with species of the genusAmnicythere. The most reliable of these characters are: a) anterior valve vestibulum from where mostly uni-ramified pore canals start, b) the entomodont hinge type with a strong anterior anti-slip tooth, a smooth posterior anti-slip bar on the left valve, and c) the hemipenis with underdeveloped lateral lobe and reduced clasping organ. From this strong evidence, the Ohrid leptocytherid species are allocated to the genusAmnicythere. Finally, a biogeographic scenario on the origin of the Ohrid leptocytherids is proposed which matches the "Lake Pannon derivate hypothesis". Close relationship of the OhridAmnicytherespecies with the non-marine leptocytherid taxa from the Neogene lakes of Central and Eastern Europe and with extant taxa from the Black and Caspian seas may indicate that the OhridAmnicytherederived from Lake Pannon species which were able to colonise lakes in Southern Europe through a stepping-stone process and subsequently to adapt to freshwater environment.
authors.affiliation: Laboratory of Limnozoology, Department of Genetics, University of Gdańsk, Kładki 24, 80-822 Gdańsk, Poland.
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Namiotko
authors.affiliation: Commission for the Stratigraphical and Palaeontological Research of Austria, Austrian Academy of Sciences, c/o Institute for Earth Sciences (Geology and Palaeontology), Karl-Franzens University, Heinrichstraße 26, A-8010 Graz, Austria.
authors.forename: Dan L
authors.initials: DL
authors.lastname: Danielopol
authors.affiliation: Department of Meteorology, Earth and Environmental Systems Institute, The Pennsylvania State University, 416 Walker Building, University Park, PA-16802, USA; Laboratoire des Sciences du Climat et de l'Environnement, Orme des Merisiers, Bâtiment 701, F-91191 Gif-sur-Yvette, France.
authors.forename: Soumaya
authors.initials: S
authors.lastname: Belmecheri
authors.affiliation: Department for Geology and Palaeontology, Universalmuseum Joanneum, Weinzöttlstraße 16, A-8045 Graz, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Gross
authors.affiliation: Laboratoire des Sciences du Climat et de l'Environnement, Orme des Merisiers, Bâtiment 701, F-91191 Gif-sur-Yvette, France.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Von Grafenstein
keywords: biosystematics; morphology; palaeobiogeography; redescription of Leptocythere karamani Klie, 1939