''Laevapex'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of small,

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does in ...

, air-breathing

limpet Limpets are a group of aquatic snails that exhibit a conical gastropod shell, shell shape (patelliform) and a strong, muscular foot. Limpets are members of the class Gastropoda, but are polyphyletic, meaning the various groups called "limpets" ...

s, aquatic pulmonate gastropod molluscs in the family

Planorbidae Planorbidae, common name the ramshorn snails or ram's horn snails, is a family of air-breathing freshwater snails, aquatic pulmonate gastropod molluscs. Unlike most molluscs, the blood of ram's horn snails contains iron-based hemoglobin inste ...

, the ram's horn snails and their allies.

Geographic distribution

The genus has a

New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. ...

distribution. It is widespread throughout the eastern United States, occurring in lakes and slow-flowing rivers.

Anatomy

These animals have a pallial lung, as do all pulmonate snails, but they also have a false gill or "

pseudobranch The pseudobranch, also pseudobranchia is the reduced first gill arch of a fish (on the inner surface of the opercle, near the junction of the preopercle) as well as a reduced "false" gill in some gastropods. In teleost fish, the pseudobranchs are ...

" which can serve perfectly well as a

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they ar ...

when they are unable to reach the surface for air. Members of this genus are characterised by their smooth

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics), a teenaged super villainess in the Marvel Universe * Ape-X, a super-intelligent ape in the Squadron Supreme universe *Apex, ...

Species

Species within the genus ''Laevapex'' include: * '' Laevapex diaphanus'' Haldeman, 1841 * ''

Laevapex fuscus ''Laevapex fuscus'', the dusky ancylid, is a species of small, freshwater, air-breathing limpet, an aquatic pulmonate gastropod mollusc or micromollusc in the family Planorbidae, the ram's horn snails and their allies. Geographic distrib ...

'' C. B. Adams, 1841 * ''

Laevapex peninsulae ''Laevapex'' is a genus of small, freshwater, air-breathing limpets, aquatic pulmonate gastropod molluscs in the family Planorbidae, the ram's horn snails and their allies. Geographic distribution The genus has a New World distribution. I ...

'' Pilsbry, 1903 * '' Laevapex vazi'' Santos, 1989 Walther (2008) considers North American ''Laevapex''

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

, collectively synonymising ''L. diaphanus'', ''L. peninsulae'' and unidentified ''Laevapex'' sp. with ''L. fuscus'', the type species.

References

External links

Planorbidae Gastropod genera {{Planorbidae-stub