Systematics and palaeobiogeography of the gastropods of the middle Miocene (Serravallian) Karaman Basin, Turkey

A systematic account of the middle Miocene late Serravallian gastropod assemblage found in the Karaman Basin of Turkey is given. In this work 437 species are recorded belonging to 252 genera, of which 60 were left in open nomenclature. Four new genera are proposed; Erentoezia nov. gen., Janssenia nov. gen., Europhos nov. gen. and Nisosyrnola nov. gen. Forty-one species are described as new; Homalopoma laleensis nov. sp., Thericium ataturki nov. sp., Tiaracerithium eceae nov. sp., Gibborissoia angulosa nov. sp., Erentoezia akpinarensis nov. sp., Rhombostoma? meesi nov. sp., Rhombostoma? daani nov. sp., Elachisina rolani nov. sp., Elachisina gofasi nov. sp., Tornus karamanensis nov. sp., Solariorbis punctatocarinatus nov. sp., Dermomurex (Trialatella) kilikiensis nov. sp., Ocinebrina perparva nov. sp., Nassarius gilii nov. sp., Nassarius barbarossai nov. sp., Nassarius erunalae nov. sp., Nassarius erentoezae nov. sp., Nassarius pseudoserrulus nov. sp., Nassarius pascaleae nov. sp., Melongena jaapi nov. sp., Polygona vermeiji nov. sp., Vexillum baluki nov. sp., Conomitra karamanensis nov. sp., Scalptia? problematica nov. sp., Tritonoharpa alanbeui nov. sp., Varioconus erunalerentoezae nov. sp., Genota pseudoelisae nov. sp., Clathurella pouweri nov. sp., Pleurotomoides isabelae nov. sp., Bela seyithasanensis nov. sp., Raphitoma spinosissima nov. sp., Raphitoma vandervoorti nov. sp., Cochlespira protomediterranea nov. sp., Clavatula labiolirata nov. sp., Clavatula seyithasanensis nov. sp., Perrona robustocarinifera nov. sp., Chrysallida majae nov. sp., Henrya wareni nov. sp., ‘Acteon’ problematicus nov. sp., Philine seyithasanensis nov. sp. and Micratys fragilissimus nov. sp. The following taxonomic changes are made: type species are designated for the turritellid genera Oligodia Handmann, 1882 and Helminthia Handmann, 1882. Trochus buchii Dubois de Montpéreux, 1831 is suppressed in favour of the senior subjective synonym Trochus catenularis von Eichwald, 1830, Turritella turris var. badensis Sacco, 1896 is suppressed in favour of the senior subjective synonym Turritella vindobonensis Handmann, 1882, Phorus gratteloupi d’Orbigny, 1852 is suppressed in favour of the senior subjective synonym Trochus conchyliophorus var. italica Grateloup, 1845, Melongena pseudobasilica Strausz, 1966 is suppressed in favour of the senior subjective synonym Melongena hungarica Csepreghy Meznerics, 1950 and Chrysallida interita van der Linden & Eikenboom, 1992 is suppressed in favour of the senior subjective synonym Parthenia (Pyrgisculus) longula Boettger, 1906. Mangilia hörnesi Brusina, 1870 is considered a nomen oblitum. Nassarius schoenni (Hoernes & Auinger, 1882) is considered a nomen protectum and Nassa laevigata Pusch, 1837 a nomen oblitum. Nassa explorata Boettger 1906 is considered a subjective synonym of Naytiopsis hypertropha (Boettger, 1906), which is chosen as the valid name of the species. Galeodes (Galeodes) thraciensis Lebküchner, 1974, is considered a nomen nudum. Raphitoma antonjanseni Marquet, 1998 is corrected to Raphitoma antonjansei. Lectotypes are designated for Conus subraristriatus Pereira da Costa, 1866 and Andonia transsylvanica (Hoernes & Auinger, 1890). The Karaman assemblages all correspond to soft bottom habitats. The fully marine layers at Seyithasan represent sandy bottom habitats, possibly with sea grass communities, deposited probably in the shallow sub-tidal zone. The clayey sediments at Akpınar correspond to shelf environments, and reflect slightly more open and deeper marine conditions than Seyithasan. Brackish deposits are also present in some localities, which probably represent lagoonal environments. The importance of the assemblage is highlighted, as it is the only rich and diversified middle Miocene assemblage known from the Mediterranean region. The assemblage is compared with those found in the middle Miocene European Atlanto–Proto-Mediterranean and Paratethyan regions and a very close correlation (72.9%) is found between the Karaman fauna and that found in the slightly younger Badenian Paratethys, which is Langhian-early Serravallian in age. As might be expected, the correlation between the Karaman Basin assemblages and those along the eastern Atlantic frontage (Aquitaine, 28.8%; Loire, 20.9% and North Sea Basin, 14.6%) grows progressively weaker northwards. The strong correlation between the Karaman and Paratethyan assemblages casts doubt on the model depicting the Badenian Paratethys as being highly endemic and suggests that the main connection between the Paratethys and the Proto-Mediterranean Sea via the TransTethyan Trench corridor in Slovenia may still have been open during the late Badenian. However, the correlation between the Karaman assemblage and the coeval Sarmatian stage Karaman taxa occurring in the Paratethys, is very low (1.6 %). At that time the Paratethys was already disconnected from the Mediterranean and had developed a highly endemic gastropoda fauna. Therefore, the Karaman assemblage shows a high correlation with the slightly older Paratethyan fully marine Badenian assemblage, corresponding with the Langhian and early Serravallian, but not to the coeval Paratethyan late Serravallian/Sarmatian assemblage.