Numerous new records of tropical non-indigenous species in the Eastern Mediterranean highlight the challenges of their recognition and identification

Abstract

New data on 52 non-indigenous mollusks in the Eastern Mediterranean Sea is reported. <i>Fossarus</i> sp. (aff. aptus sensu Blatterer 2019), <i>Coriophora lessepsiana</i> Albano, Bakker & Sabelli, <b>sp. nov.</b>, Cerithiopsis sp. aff. pulvis, <i>Joculator problematicus</i> Albano & Steger, <b>sp. nov.</b>, <i>Cerithiopsis</i> sp., <i>Elachisina</i> sp., Iravadia aff. elongata, <i>Vitrinella</i> aff. <i>Vitrinella</i> sp. 1 (sensu Blatterer 2019), <i>Melanella orientalis</i>, Parvioris aff. dilecta, Odostomia cf. dalli, <i>Oscilla virginiae</i>, <i>Parthenina cossmanni</i>, <i>Parthenina typica</i>, <i>Pyrgulina craticulata</i>, <i>Turbonilla funiculata</i>, <i>Cylichna collyra</i>, <i>Musculus coenobitus</i>, Musculus aff. viridulus, <i>Chavania erythraea</i>, Scintilla cf. violescens, <i>Iacra seychellarum</i> and <i>Corbula erythraeensis</i> are new records for the Mediterranean. An unidentified gastropod, Skeneidae indet., <i>Triphora</i> sp., <i>Hypermastus</i> sp., <i>Sticteulima</i> sp., Vitreolina cf. philippi, <i>Odostomia</i> (s.l.) sp. 1, <i>Henrya</i> (?) sp., and Semelidae sp. are further potential new non-indigenous species although their status should be confirmed upon final taxonomic assessment. Additionally, the status of <i>Dikoleps micalii</i>, <i>Hemiliostraca clandestina</i> <b>comb. nov.</b> and <i>H. athenamariae</i> <b>comb. nov.</b> is changed to non-indigenous, range extensions for nine species and the occurrence of living individuals for species previously recorded from empty shells only are reported. <i>Opimaphora blattereri</i> Albano, Bakker & Sabelli, <b>sp. nov.</b> is described from the Red Sea for comparison with the morphologically similar <i>C. lessepsiana</i> Albano, Bakker & Sabelli, <b>sp. nov.</b> The taxonomic part is followed by a discussion on how intensive fieldwork and cooperation among institutions and individuals enabled such a massive report, and how the poor taxonomic knowledge of the Indo-Pacific fauna hampers non-indigenous species detection and identification. Finally, the hypothesis that the simultaneous analysis of quantitative benthic death assemblages can support the assignment of non-indigenous status to taxonomically undetermined species is discussed.