A review of occurrence, distribution and alien status of Notodiaphana atlantica Ortea, Moro and Espinosa, 2013 and Liloa mongii (Audouin, 1826) (Mollusca: Heterobranchia) in the Mediterranean Sea

Luigi Romani, Lionello P. Tringali, Fabio Crocetta

Paper category: Original research paper
Corresponding author: Fabio Crocetta (fabio.crocetta@szn.it)
DOI: 10.2478/oandhs-2021-0022
Received: 05/12/2020
Accepted: 21/01/2021
Full text: here

Citation: Romani,L.,Tringali,L. & Crocetta,F.(2021).A review of occurrence, distribution and alien status of Notodiaphana atlantica Ortea, Moro and Espinosa, 2013 and Liloa mongii (Audouin, 1826) (Mollusca: Heterobranchia) in the Mediterranean Sea. Oceanological and Hydrobiological Studies,50(3) 259-268. https://doi.org/10.2478/oandhs-2021-0022


Notodiaphana atlantica and Liloa mongii are two cephalaspidean species described respectively from the Atlantic Ocean and the Red Sea, and considered widespread in their native ranges. Both species have also been recently recorded from the Mediterranean Sea, prompting some authors to consider them alien. Notwithstanding clear morphological differences in their shells, the two species have often been confused or misidentified in the literature, or specimens have been described with incorrect locality data. We hereby review the occurrence, distribution and status of both species in the Mediterranean Sea based on published data and examination of new material. Notodiaphana atlantica is considered a cryptogenic species with a range spanning from the western to eastern part of the basin. The presence of L. mongii in the Mediterranean is questioned until specimens that can be reliably assigned to this taxon or to any congeneric species are found in the area. Alien species inventories play an important role in regional policy and management decisions, thus requiring a high degree of confidence in the validity of species identification and their non-indigenous status. The present paper adds further evidence of the excess of “bibliographically introduced” alien records and reiterates the need for periodic re-evaluation of published data.


The following people offered assistance during the fieldwork, research on the material in public and private collections, bibliographic research, or provided useful advice: Franco Agamennone (Pescara, Italy), Cesare Bogi (Livorno, Italy), Alberto Cecalupo (Milano, Italy), Gian Paolo Franzoni (Tortoreto, Italy), Virginie Héros (Paris, France), Harry Lee (Jacksonville, FL, USA), Philippe Maestrati (Paris, France), Pasquale Micali (Fano, Italy), Constantine Mifsud (Rabat, Malta), Leopoldo Moro (Santa Cruz de Tenerife, Spain), Andrea Nappo (Pomezia, Italy), Jesús Ortea (Oviedo, Spain), Attilio Pagli (Empoli, Italy), Alessandro Raveggi (Firenze, Italy), Walter Renda (Amantea, Italy), Emilio Rolán (Vigo, Spain), Maria Scaperrotta (Firenze, Italy), and Franco Siragusa (Livorno, Italy); specifically Stefano Bartolini (Firenze, Italy) and Edoardo Perna (Napoli, Italy) allowed us to use their own photographs. We are grateful to all of them.


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