''Nerita japonica''( ja, アマガイ(蜑貝), Amagai, ko, 갈고둥, Galgodung) is a

species In biology, a species is the basic unit of 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 the appropriate s ...

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a marine

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

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 e ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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: ...

. ''Nerita japonica'' is the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of the subgenus '' Heminerita'' von Martens, 1887.

Description

Adult shells are 10–20 mm in both shell diameter and shell height. The shell is hemispherical and hard. The body layer (the lowest part of the winding) is greatly developed, like other molluscs of the family Nebulaidae. The spire has four floors, but it is small and protrudes obliquely upward. The shell surface is dull and varies from weak spiral ribs and growth lines to almost smooth. The ground color is black, and there are yellow-white to orange triangular spots and lightning-bolt-shaped vertical lines, but it is rich in individual variation and various patterns can be seen. In some older individuals, the surface of the shell is abraded to a uniform yellow-gray to gray-brown color. The shell mouth is D-shaped, and a yellow smooth layer spreads around it. 黒田徳米・波部忠重・大山桂生物学御研究所編『相模湾産貝類』1971年丸善 ISBN 4621012177内田亨監修『学生版日本動物図鑑』北隆館 1948年初版・2000年重版 ISBN 4832600427波部忠重監修『学研中高生図鑑貝I』1975年波部忠重・小菅貞男『エコロン自然シリーズ貝』1978年刊・1996年改訂版 ISBN 9784586321063小菅貞男『ポケット図鑑日本の貝』1994年成美堂出版 ISBN 4415080480 奥谷喬司編『日本近海産貝類図鑑』（アマオブネガイ科解説 : 土屋光太郎）2000年東海大学出版会 ISBN 9784486014065三浦知之『干潟の生きもの図鑑』2007年南方新社 ISBN 9784861241390。

Distribution

It is a hemispherical snail found on reefs and rocky areas along the coasts of southern Honshu, Shikoku, Kyushu, and the southern part of the Korean Peninsula .It has a narrow distribution area as a member of the family Amaranthus, and many related species are distributed in the tropical waters south of the Nansei Islands, but this species is not distributed 行田義三『貝の図鑑採集と標本の作り方』2003年南方新社 ISBN 4931376967

References

External links

갈고둥
Neritidae Gastropods described in 1860 {{Neritidae-stub