Aplexa

Aplexa
Shells of Aplexa hypnorum
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Superorder:	Hygrophila
Family:	Physidae
Genus:	Aplexa Fleming, 1820 [1]
Type species
Bulla hypnorumLinnaeus, 1758
Synonyms
AplectaHerrmannsen, 1846 (invalid: an incorrect subsequent spelling of Aplexa) Physa (Aplecta)Herrmannsen, 1846(invalid: an incorrect subsequent spelling of Aplexa)

Aplexa is a genus of small, left-handed or sinistral, air-breathing freshwater snails, aquatic pulmonate gastropod mollusks in the family Physidae. ^[2]

Shell description

These small snails are quite distinctive, because they have shells that are sinistral, which means that if you hold the shell such that the spire is pointing up, then the aperture is on the left-hand side.

The shells of Aplexa species have a long and large aperture, a relatively high and pointed spire, and no operculum. The shells are thin and corneous and rather transparent.

Only two species are still extant.

Species

Species in the genus Aplexa include:

• † Aplexa atava White, 1877
• † Aplexa breviturrita Y.-T. Li, 1983
• † Aplexa canculae Pacaud, 2022
• † Aplexa cotiensis Pacaud, 2022
• † Aplexa delicata Y.-T. Li, 1984
• † Aplexa disjuncta (White, 1879)
• † Aplexa dumonti (Briart & Cornet, 1887)
• † Aplexa fusioidea Tolstikova, 1979
• † Aplexa fuxinensis X.-H. Yu, 1987
• † Aplexa galloprovincialis (Matheron, 1843)
• † Aplexa gardanens (Matheron, 1843)
• † Aplexa gigantea (Michaud, 1837)
• † Aplexa grasseti (Matheron, 1878)
• † Aplexa heberti (Deshayes, 1863)
• Aplexa hypnorum (Linnaeus, 1758) - the moss bladder snail
• † Aplexa iota Pacaud, 2022
• † Aplexa jaimei (Hermite, 1879)
• † Aplexa kasekikabe (Isaji, 2010)
• † Aplexa lipasma Y.-T. Li, 1984
• † Aplexa lubrica W. Yü, 1965
• † Aplexa macerata (Russell, 1937)
• † Aplexa macilenta Y.-T. Li, 1983
• † Aplexa magna Y.-T. Li, 1984
• † Aplexa militaria (Yen & Reeside, 1946)
• † Aplexa montensis (Briart & Cornet, 1887)
• † Aplexa morrisonana (Yen & Reeside, 1946)
• † Aplexa morrisoni MacNeil, 1939
• † Aplexa normalis Y.-T. Li, 1985 (accepted > unreplaced junior homonym of Aplexa hypnorum normalisH. Beck, 1838; no replacement name or synonym known.
• † Aplexa oryza Pacaud, 2022
• † Aplexa panshanensis L.-S. Huang, 1987
• † Aplexa praelonga (Matheron ex Heer, 1861)
• † Aplexa preciosa Y.-T. Li, 1984
• † Aplexa primigenia (Deshayes, 1863)
• † Aplexa prisca (Noulet, 1854)
• † Aplexa pseudogigantea (F. Sandberger, 1870)
• † Aplexa pulchella (A. d'Orbigny, 1850)
• † Aplexa raris Y.-T. Li, 1984
• † Aplexa ricei (Russell, 1957)
• † Aplexa risleius Pacaud, 2022
• † Aplexa subelongata (Meek & Hayden, 1856)
• † Aplexa subhypnorum (Gottschick, 1920)
• Aplexa venezuelensis (E. von Martens, 1859)
• † Aplexa xichuanensis Y.-T. Li, 1983
• † Aplexa yangxiensis Y.-T. Li, 1987
• † Aplexa zhui Pacaud, 2022

=Synonyms

• † Aplexa brevispirata(Cossmann & Pissaro, 1913): synonym of † Aplexa cotiensisPacaud, 2022 (junior homonym of Physa (Isodora) tchadiensis brevispirataGermain, 1905; Aplexa cotiensisPacaud, 2022 is a replacement name)
• Aplexa elongata(Say, 1821) - the lance aplexa: synonym of Sibirenauta elongata (Say, 1821)
• † Aplexa rivalis(Maton & Rackett, 1807): synonym of Physella acuta (Draparnaud, 1805) (junior synonym)

References

1. Fleming J. (1830). Mollusca. pp. 598-635, in: Brewster D. The Edinburgh Encyclopædia. In eighteen volumes. Volume XIV [= 14] [MED-MUS]. pp. [1], 1-748, Pl. CCCLXXII-CCCC [= 372-400]. Edinburgh. (Blackwood).
2. MolluscaBase eds. (2025). MolluscaBase. Aplexa J. Fleming, 1820. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=820399 on 2025-09-17

External links

• Taylor, D.W. (2003). "Introduction to Physidae (Gastropoda: Hygrophila); biogeography, classification, morphology" (PDF). Revista de Biología Tropical. 51 (1): 197–263.

Further reading

• "Genus summary for Aplexa". AnimalBase.
• Janus, Horst, 1965. ‘’The young specialist looks at land and freshwater molluscs’’, Burke, London