Mollusc species from the Pontocaspian region - an expert opinion list Author Wesselingh, Frank Naturalis Biodiversity Center, Leiden, Netherlands Author Poorten, Jan Johan ter Field Museum of Natural History, Chicago, United States of America Author Kijashko, Pavel Moscow State University, Moscow, Russia Author Albrecht, Christian Justus Liebig University, Giessen, Germany Author Anistratenko, Olga Yu Schmalhausen Instite of Zoology, National Academy of Sciences of Ukraine, Kiev, Ukraine & Institute of Geological Sciences, National Academy of Sciences of Ukraine, KievUkraine Author Frolov, Pavel Saint-Petersburg State University, Saint Petersburg, Russia Author Gándara, Alberto Martinez Grigore Artipa National Museum of Natural History, Bucharest, Romania Author Gittenberger, Arjan Gittenberger Marine Research, Inventory & Strategy, Leiden, Netherlands Author Gogaladze, Aleksandre Naturalis Biodiversity Center, Leiden, Netherlands Author Mikhail Karpinsky Russian Federal Research Institute of Fisheries and Oceanography, Moscow, Russia Author Popa, Luis Grigore Antirpa National Museum of Natural History, Bucharest, Romania Author Sands, Arthur F Justus Liebig University, Giessen, Germany Author Vandendorpe, Justine Justus Liebig University, Giessen, Germany Author Wilke, Thomas Justus Liebig University Giessen Germany text ZooKeys 2019 827 31 124 http://dx.doi.org/10.3897/zookeys.827.31365 journal article http://dx.doi.org/10.3897/zookeys.827.31365 1313-2970-827-31 10B663895E424E5287D8F49E2405D651 Subfamily Caspiinae Dybowski, 1913 Remarks. The distinction of the genera Caspia , Ulskia , and Clathrocaspia follows Neubauer et al. (2018) . The three taxa are differentiated based on details of the protoconch and the expression of teleoconch sculpture. Caspia s. s. is characterised by a single distinct but fine spiral keel below the suture. It is usually smooth, yet within the type species some reticulate ornament can be found. Species of Clathrocaspia expose a distinctive, reticulate pattern on the teleoconch and a malleate protoconch with faint spiral threads. The aperture of Clathrocaspia often develops a distinct flat base. The discinction of the two genera is subject of current research. Ulskia also has a malleate protoconch but with more distinct spiral threads; teleoconch sculpture is occasionally present as minute elongate nodules.