''Clithon retropictum''( ko, 기수갈고둥, ja, 石蜑螺) is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

of freshwater and

brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

snail A snail is, in loose terms, a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class G ...

with an operculum, a

nerite Neritidae, common name the nerites, is a taxonomic family of small to medium-sized saltwater and freshwater snails which have a gill and a distinctive operculum. MolluscaBase eds. (2021). MolluscaBase. Neritininae Poey, 1852. Accessed through: ...

. It is an aquatic gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is es ...

in the family

Neritidae Neritidae, common name the nerites, is a taxonomic family of small to medium-sized saltwater and freshwater snails which have a gill and a distinctive operculum. MolluscaBase eds. (2021). MolluscaBase. Neritininae Poey, 1852. Accessed through: ...

, the nerites.

Distribution

This species occurs in Japan:

Honshu , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island ...

Kyushu is the third-largest island of Japan's five main islands and the most southerly of the four largest islands ( i.e. excluding Okinawa). In the past, it has been known as , and . The historical regional name referred to Kyushu and its surroun ...

and

Shikoku is the smallest of the four main islands of Japan. It is long and between wide. It has a population of 3.8 million (, 3.1%). It is south of Honshu and northeast of Kyushu. Shikoku's ancient names include ''Iyo-no-futana-shima'' (), ...

.Its habitat is also located in South Korea near Jeju.

Description

Habitat

This nerite lives in brackish water as well as freshwater.

Feeding habits

''Clithon retropictum'' is

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

species.

Life cycle

''Clithon retropictum'' is

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), a ...

.FURUJO Yuki & TOMIYAMA Kiyonori
''Distribution and Microhabitat of Coexisting Two Freshwater Snail Species, Semisulcospira libertina (Gould) (Prosobranchia; Pleuroceridae) and Clithon retropictus (Martens) (Prosobranchia: Neritidae)''
The Japanese journal of malacology. Venus, Vol. 59, No. 3(20000930), pp. 245-260. Juveniles hatch from eggs in September. The lifespan of ''Clithon retropictum'' is up to 12 years and it belongs among the most long-lived of freshwater gastropods.

Parasites

* ''

Vibrio parahaemolyticus ''Vibrio parahaemolyticus'' (V. parahaemolyticus) is a curved, rod-shaped, Gram-negative bacterium found in the sea and in estuaries which, when ingested, may cause gastrointestinal illness in humans. ''V. parahaemolyticus'' is oxidase positiv ...

Status

The species is considered as a second grade endangered species by the Korean ministry of environment.The occurrence of Clithon retropictus (v. Martens, 1879) (Gastropoda: Neritidae) in an unusual habitat, northern Jeju Island, Republic of Korea Ronald G. Noseworthy, Hee-Jung Lee & Kwang-Sik Choi Ocean Science Journal volume 48, pages259–262
/ref>

References

External links

* https://web.archive.org/web/20070909103814/http://shell.kwansei.ac.jp/~shell/pic_book/data08/r000792.html photos of shells * https://web.archive.org/web/20080907101015/http://www.gastropods.com/8/Shell_8638.html photos of shells Neritidae Gastropods described in 1879 Endangered species {{Neritidae-stub