''Otukaia kiheiziebisu'' 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 ...

of sea snail, a marine 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 e ...

in the

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

Calliostomatidae Calliostomatidae is a family of sea snails within the superfamily Trochoidea and the clade Vetigastropoda.Gofas, S. (2013). Calliostomatidae. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdeta ...

. The type specimens were collected by amateur conchologist Mr. Kiheizi Oosima in 1938. The specific name ''kiheiziebisu'' is in honour of him. The new species was originally described as ''Calliostoma kiheiziebisu'' by the Japanese

malacologist Malacology is the branch of invertebrate zoology that deals with the study of the Mollusca (mollusks or molluscs), the second-largest phylum of animals in terms of described species after the arthropods. Mollusks include snails and slugs, clams, ...

Yanosuke Otuka (1903-1950) in 1939. ''Otukaia kiheiziebisu'' is the type species of the genus '' Otukaia'' Ikeba, 1942. Some authors recognize ''Otukaia'' as a separate genus.Vilvens & Sellanes (2006). '' The Nautilus'' 120(1): 15-20.

Description

The

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...

is large, conical, thin, semitransparent, pale cinnamon pink in colour with pearly lustre. The shell has 8.5

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

. One and a half coils of nuclear portion of whorls are rounded in outline, smooth, polished on the surface. Subsequent whorls are sculptured with four strong, beaded spiral keels and very fine lines, which are only visible under a magnifying

lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements ...

, and with fine oblique lines of growth. The uppermost spiral keel is situated on the sub

sutural Wormian bones, also known as intrasutural bones or sutural bones, are extra bone pieces that can occur within a suture (joint) in the skull. These are irregular isolated bones that can appear in addition to the usual centres of ossification of ...

area. The second and the third spiral keels are dividing the surface of whorl into three parts with unequal interval; the uppermost part the broadest, having angle of about 120° to the middle one, weakly sculptured with a thread and many exceedingly fine spiral lines near the body whorl. The lowest one is the narrowest of them all. The lowest spiral keel is concealed with succeeding whorl. The number of beads on the upper most spiral keel is ca 165-177 on the last whorl, ca 130 on penultimate whorl, ca 80 on the sixth whorl, ca 50 on the fifth whorl, ca 42 on the fourth whorl, ca 28 on the third whorl and ca 19 on the second whorl. The base is sculptured with about 40 spiral threads. The inner surface is smooth, pearly lustrous, ornamented with four spiral dull grooves which correspond to the outer keels respectively. Callus is extending over the umbilicus so as to occlude it completely, giving a shape of oblique columellar end. The height of the shell is 30 mm. The width of the shell is 33 mm. The operculum is small, round, horny, thin, translucent, marked with a fine spiral line which coils about 13 in number. The diameter of the operculum is about 13 mm. ''Otukaia kiheiziebisu'' is very similar to '' Calliostoma kounjiana'' Yokoyama in general outline, and in

sculpture Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable ...

on the surface, but it differs from ''Calliostoma kounjiana'' in having the spirally sculptured base and the beaded spiral keels, while ''Calliostoma kounjiana'' is quite smooth both on spiral keel and the base. Any other species reported from the northern

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

has much thicker shell and more complicated sculptures than ''Otukaia kiheiziebisu''.

Distribution

The type locality is Kasimanada 600 m in depth, off the east coast of

Ibaraki Prefecture is a prefecture of Japan located in the Kantō region of Honshu. Ibaraki Prefecture has a population of 2,871,199 (1 June 2019) and has a geographic area of . Ibaraki Prefecture borders Fukushima Prefecture to the north, Tochigi Prefecture ...

, Japan.

References

This article incorporates

copyright-free The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because those rights have expired, ...

text from the reference. * Hasegawa K. (2009) ''Upper bathyal gastropods of the Pacific coast of northern Honshu, Japan, chiefly collected by R/V Wakataka-maru''. In: T. Fujita (ed.), Deep-sea fauna and pollutants off Pacific coast of northern Japan. National Museum of Nature and Science Monographs 39: 225-383.

External links

photo of the type specimen (holotype)
in the University Museum,

The University of Tokyo , abbreviated as or UTokyo, is a public research university located in Bunkyō, Tokyo, Japan. Established in 1877, the university was the first Imperial University and is currently a Top Type university of the Top Global University Project by ...

. * http://clade.ansp.org/obis/search.php/71835 * {{Taxonbar, from=Q7110043 kiheiziebisu Gastropods described in 1939