Physa

Updated on Oct 25, 2023

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Kingdom Animalia Family Physidae Tribe Physini Higher classification Physidae Rank Genus		Superfamily Planorboidea Subfamily Physinae Scientific name Physa Phylum Mollusca

Lower classifications Physa fontinalis, Physa marmorata

Snail egg just born physa accuta 240x 600x

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

These snails eat algae, diatoms and detritus.

Snail egg physa accuta 240x

Anatomy

Members of the freshwater pulmonate family Physidae possess a complex of muscles that is unique amongst gastropods. This complex was given the name "physid musculature". The physid musculature has two main components, the physid muscle sensu stricto and the fan muscle. The physid musculature is responsible for a unique ability of physids to rapidly flick their shells from side to side — a reaction that frequently enables them to escape predation.

Shell description

Physa hbsbishopmuseumorgwaipioimagesCrittersmollus

These small snails, like all the species in the family Physidae, have shells that are sinistral, which means that when the shell is held with the spire pointing up and the aperture facing the viewer, then the aperture is on the left-hand side.

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

Species

Species in the genus include:

Physa acuta Draparnaud, 1805

Physa ancillaria (Say, 1825) - Pumpkin Physa

† Physa aridi Mezzalira, 1974 - fossil from Brazil

Physa carolinae Wethington, Wise & Dillon, 2009

Physa concolor

Physa fontinalis (Linnaeus, 1758) - Fountain bladder snail - type species

Physa hordacea (I. Lea, 1864)

Physa jennessi Dall, 1919

Physa lordi (Baird, 1863)

Physa marmorata Guilding, 1828 - synonyms: Physa mosambiquensis Clessin, 1886 and Physa waterloti

Physa megalochlamys Taylor, 1988

† Physa mezzalirai Ghilardi, Carbonaro & Simone, 2011 - fossil from Brazil

Physa natricina Taylor, 1988

Physa nuttalli

Physa propingua (Tryon, 1865)

Physa pumilia Conrad, 1834

Physa siberica Westerlund, 1876

Physa skinneri Taylor, 1954

Physa vernalis Taylor et Jokinen, 1984

Physa sp., Lake Winnipeg Physa, lives in Manitoba in Canada. It was classified as endangered by COSEWIC. COSEWIC recommendation has been forwarded to the Minister of the Environment of Canada and a decision for listing at the List of Wildlife Species at Risk of the Canadian Species at Risk Act was pending in 2005.

Synonyms:

Physa acuta Draparnaud, 1805, Physa heterostropha (Say, 1817), Physa integra (Haldeman, 1841) and Physa natricina Taylor, 1988 are synonyms of Physella acuta (Draparnaud, 1805)

Physa columbiana (Hemphill, 1890) is a synonym for Physella columbiana (Hemphill, 1890)

Physa gyrina (Say, 1821) is a synonym for Physella gyrina'' (Say, 1821)

References

Physa Wikipedia

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