''Bayerotrochus teramachii'', is a species of

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 ...

mollusc 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 esti ...

in the family

Pleurotomariidae Pleurotomariidae, common name the "slit snails", is a family of large marine gastropods in the superfamily Pleurotomarioidea of the subclass Vetigastropoda. This family is a very ancient lineage; there were numerous species in the geological pas ...

Description

The shell has a depressed turbinate shape with an apical spire angle of approximately 98 degrees, with inflated body whorls that are exponential in expansion, a clearly impressed suture, and the periphery is rounded and indistinct. The base is highly inflated with a small columellar callus at the center covering roughly 22 percent of the base area. The aperture is oval, the slit is positioned roughly halfway between the periphery and the suture and is relatively long, about 21 percent of the circumference. The shell is lightly sculptured with numerous spiral cords over 30 above the

selenizone A selenizone (from the Greek "selene" meaning "moon", and "zone" meaning "girdle") is an anatomical structure that exists in the shells of some families of living sea snails: the slit shells, the little slit shells and the abalones, which are m ...

(the area where the shell growth filled in the slit) and 17 to 19 spiral cords below the selenizone, crossed by strong axial growth lines which gives the effect of a coarse rectangular pattern. The cords are made up of very fine hemispherical beads. The base has fine microscopically beaded spiral cords. The

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...

and primary whorls are a dull cream color or white, the rest of the shell is a golden orange, with a golden metallic iridescent sheen. The entire teleoconch (body whorls) has deep orange axial streaks and flammules. The selenizone has 4 to 5 spiral cords and is usually concave in profile. The base is the same base color as the body, and the interior of the aperture is thinly

nacre Nacre ( , ), also known as mother of pearl, is an organicinorganic composite material produced by some molluscs as an inner shell layer; it is also the material of which pearls are composed. It is strong, resilient, and iridescent. Nacre is f ...

ous (pearly). The operculum is roughly circular, light brown, multispiral, and chitinous. Size range: 64 to 175 mm diameter.Anseeuw, P. & Goto, Y., ''The Living Pleurotomariidae'' (1996), Elle Scientific Publications, Osaka Japan, pp. 202, at pp. 154–155.Original description: Tokubei Kuroda, ''A new Pleurotomaria from Japan with a Note on a specimen of Pleurotomaria rumphii Schepman collected from Taiwan: Perotrochus teramachii n. sp.'' (1955), Venus (The Japanese Journal of Malacology) Vol. 18:211–212.

Distribution

This species has been found at depths of 180 to 500 meters over a large area of the North West Pacific from

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

to the South China Sea, and across to Indonesia and the Philippines.

References

* Williams S.T., Karube S. & Ozawa T. (2008) ''Molecular systematics of Vetigastropoda: Trochidae, Turbinidae and Trochoidea redefined''. Zoologica Scripta 37: 483–506.

External links

* Pleurotomariidae Gastropods described in 1955 {{Pleurotomariidae-stub