# Clio (gastropod)

The genus Clio is a taxonomic group of small floating sea snails, pelagic marine opisthobranch gastropod mollusks, the sole genus belonging to the family Cliidae
All species within this genus exhibit a bilaterally symmetrical shell that is either straight or slightly curved dorso-ventrally towards the apex. The shell cross-section is elliptical to triangular. The protoconch is distinct and globular or elliptical, often bearing a spine at its tip.
While some species are classified within subgenera (e.g., Clio s.str., Balantium Bellardi, 1872, Bellardiclio Janssen, 2004), the majority of species remain unassigned to one of these.
Numerous fossil species have been described.

## Species

Recognised extant species are:
* † Clio aichinoi Checchia-Rispoli, 1921
* Clio andreae (Boas, 1886)
** Distribution : north Atlantic, bathypelagic species.
* Clio bartletti van der Spoel, 1978
** Distribution: central Atlantic (Pleistocene fossil).
* † Clio bellardii Audenino, 1895
* † Clio berglundorum Squires, 1989
* † Clio blinkae A. W. Janssen, 1989
* † Clio braidensis (Bellardi, 1873)
* † Clio calix (Bellardi, 1873)
* Clio campylura (Tesch, 1948)
* † Clio carinata Audenino, 1895 †
* † Clio chadumica Korobkov, 1966
* Clio chaptalii J. E. Gray, 1850
** Distribution : tropical, circumglobal.
* † Clio colina A. W. Janssen & Zorn, 2001
* Clio convexa convexa (Boas, 1886)
** Distribution: tropical, Indo-Pacific
* Clio convexa cyphosa Rampal, 2002
** Distribution: Red Sea and Gulf of Aden.
* Clio cuspidata (Bosc, 1802)
** Distribution : tropical/subtropical, circumglobal.
* † Clio distefanoi Checchia-Rispoli, 1921
* † Clio fallauxi (Kittl, 1886)
* Clio flabelliforme (Blankenhorn, 1889)
* † Clio gailae Goedert & A. W. Janssen, 2012
* † Clio ghawdexensis A. W. Janssen, 2003
* † Clio giulioi A. W. Janssen, 1995
* † Clio goedertorum Squires, 1989
* † Clio guidottii Simonelli, 1896
* † Clio hataii (H. Noda, 1972)
* † Clio ichishiensis (Shibata, 1983)
* † Clio irenae A. W. Janssen, 1989
* † Clio itoigawai (Shibata, 1983)
* † Clio jacobae A. W. Janssen, 1989
* † Clio kendacensis P. Jung, 1971
* † Clio lavayssei Rutsch, 1934
* † Clio lozoueti A. W. Janssen, 2010
* † Clio lucai A. W. Janssen, 2000
* † Clio merijni A. W. Janssen, 2012
* † Clio multicostata (Bellardi, 1873)
* † Clio nielseni A. W. Janssen, 1990
* † Clio oblonga Rampal, 1996
* † Clio ortheziana (Benoist, 1889)
* Clio orthotheca (Tesch, 1904)
* † Clio pauli A. W. Janssen, 1989
* † Clio pedemontana (C. Mayer, 1868)
* Clio piatkowskii van der Spoel, Schalk & Bleeker, 1992
** Distribution: Antarctic.
* Clio polita Pelseneer, 1888
* † Clio pulcherrima (Mayer, 1868)
* Clio pyramidata Linnaeus, 1767
** Distribution : north Atlantic
** Height : to over 20 mm.
Formae:
*** forma excisa van der Spoel, 1963
*** forma lanceolata Lesueur, 1813 (tropical/subtropical, circumglobal)
*** forma martensi (Pfeiffer, 1880) ??
*** forma sulcata (Pfeffer, 1879)
The true status of these formae has to be evaluated, they might be real formae, subspecies, or even species.
* Clio recurva (Children, 1823)
** Distribution : tropical-subtropical, circumglobal (bathypelagic species)**
*** Height: to over 30 mm
* † Clio ricciolii (Calandrelli, 1844)
* † Clio saccoi Checchia-Rispoli, 1921
* † Clio scheelei (Munthe, 1888)
* † Clio shibatai Ujihara, 1996
* † Clio sulcosa (Bellardi, 1873)
* † Clio triplicata Audenino, 1895
* † Clio vasconiensis A. W. Janssen, 2010
* † Clio vilis A. W. Janssen, 2012

### Species brought into synonymy

* Clio antarctica Dall, 1908: synonym of Clio pyramidata antarctica Dall, 1908 accepted as Clio pyramidata Linnaeus, 1767 (superseded combination)
* Clio australis: synonym of Clione limacina australis (Bruguière, 1792)
* Clio borealis (Pallas, 1774): synonym of Clione limacina (Phipps, 1774)
* Clio helicina Phipps, 1774: synonym of Limacina helicina (Phipps, 1774)
* Clio sulcata (Pfeffer, 1879): synonym of Clio pyramidata f. sulcata (Pfeffer, 1879) accepted as Clio pyramidata Linnaeus, 1767