Thalassopterus
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Thalassopterus zancleus is a species of swimming sea slug, a shell-less pelagic marine opisthobranch gastropod mollusk in the family Clionidae.<ref>Gofas, S. (2009). Thalassopterus zancleus Kwietniewski, 1910. In: Bouchet, P.; Gofas, S.; Rosenberg, G. World Marine Mollusca database. Accessed through the World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=139183 on 2010-09-16</ref>
Thalassopterus zancleus is the only species in the monotypic genus Thalassopterus. It is known only from juveniles stages.<ref>"Thalassopterus zancleus". Marine Species Identification Portal, accessed 16 September 2010.</ref> Adults have not yet been found.