Calliostoma kiheiziebisu
Encyclopedia
Otukaia kiheiziebisu is a species
of sea snail
, a marine gastropod mollusk in the family
Calliostomatidae
.
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 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.
is large, conical, thin, semitransparent, pale cinnamon pink in colour with pearly lustre. The shell has 8.5 whorls
. 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
, and with fine oblique lines of growth. The uppermost spiral keel is situated on the subsutural 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
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 has much thicker shell and more complicated sculptures than Otukaia kiheiziebisu.
, Japan.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
, a marine gastropod mollusk in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Calliostomatidae
Calliostomatidae
Calliostomatidae is a family of sea snails within the superfamily Trochoidea and the clade Vetigastropoda.- Description :The Calliostomatidae are unusually diverse. They are characterized by a stepped spire and a pointy aperture. They may possess or lack an umbilicus. The columella is sometimes...
.
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 Yanosuke Otuka (1903-1950) in 1939.
Otukaia kiheiziebisu is the type species of the genus Otukaia
Otukaia
Otukaia is a genus of medium-sized sea snails, marine gastropod molluscs in the family Calliostomatidae, the top shells. Otukaia has long been considered a subspecies of Calliostoma and is still treated as such by many authorities....
Ikeba, 1942.
Some authors recognize Otukaia as a separate genus.
Description
The shellGastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
is large, conical, thin, semitransparent, pale cinnamon pink in colour with pearly lustre. The shell has 8.5 whorls
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
. 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
Lens (optics)
A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element...
, and with fine oblique lines of growth. The uppermost spiral keel is situated on the subsutural 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
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
. 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
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
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 (mollusc)
The sculpture of a mollusc shell is the three-dimensional ornamentation on the outer surface, as distinct from the basic shape of the shell itself or colouration. Sculpture may be concave as well as convex. Sometimes it has microscopic detail. Sculpture refers to the calcareous outer layer, not the...
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 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 PrefectureIbaraki Prefecture
is a prefecture of Japan, located in the Kantō region on the main island of Honshu. The capital is Mito.-History:Ibaraki Prefecture was previously known as Hitachi Province...
, Japan.
External links
- photo of the type specimen (holotype) in the The University Museum, The University of Tokyo.
- http://clade.ansp.org/obis/search.php/71835