''Spectamen mutabile'' 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 sea snail, a

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

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 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 ...

Solariellidae Solariellidae is a family of small sea snails, marine gastropod mollusks in the superfamily Trochoidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).Gofas, S. (2011). Solariellidae. Accessed through: World Register ...

.Bouchet, P. (2013). Spectamen mutabilis (Schepman, 1908). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=741733 on 2013-12-09 ;Variety: * ''Spectamen mutabile var. plicifera'' (Schepman, 1908)

Description

(Original description by M. Schepman) The height of the shell attains 4¾ mm, its diameter 6 mm. The trochiform shell is moderately strong. it is yellowish, with a rose coloured zone on the upper part of the lower

whorl 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 flo ...

s, the upper ones are nacreous. The shell contains 5½ whorls. The nucleus is smooth, followed by a whorl with 4 or 5 raised striae, and by about four ones provided with two distinct keels, of which one, at a little distance from the suture, the other one at the periphery, accompanied on the body whorl by a third keel, at a little distance from the periphery, nearly on the base. These three keels are in typical specimens adorned by sharp nodules, about 30 on the upper keel, 38 on the peripheral one, and 34 on the visible part of the lower one. Moreover there are 2 raised spiral striae between suture and upper keel, 5 between this and the peripheral one and 2 in the space between periphery and lower keel. This concerns the body whorl; on the upper ones, the finer sculpture disappears gradually. The

umbilicus Umbilicus may refer to: *The navel or belly button *Umbilicus (mollusc), a feature of gastropod, Nautilus and Ammonite shell anatomy * ''Umbilicus'' (plant), a genus of over ninety species of perennial flowering plants *Umbilicus urbis Romae The ...

is bordered by a row of coarse, compressed beads, 17 in number. The space between the basal and the umbilical keel contains 5 smooth lirae. The lower whorls have a distinct, nearly horizontal space, from the suture towards the upper keel, with small, radiating plicae, corresponding to the nodules. The spaces above and below the peripheral keel are slightly concave, the suture laying by this construction in a sort of canal. The base of the shell is nearly flat, but slightly convex. The umbilicus is funnel-shaped, rather large, pervious, its wall with raised, concentric and radiating striae, more or less beade. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An ...

is rounded-quadrangular, with angles at the ends of the keels, especially of the umbilical one. The margin is sharp. The

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the ...

is curved and slightly reflected at the upper part. The interior of aperture is smooth and nacreous. The operculum is many-whorled, outer 2 whorls broad;. The whorlsare sculptured by radiating and concentric striae, causing a latticed appearance, radiating striae stronger on the distal half of each whorl.Schepman 1908-1913, The Prosobranchia of the Siboga Expedition; Leyden,E. J. Brill,1908-13
(described as ''Solariella mutabilis'')

Distribution

This marine species occurs off

Timor Timor is an island at the southern end of Maritime Southeast Asia, in the north of the Timor Sea. The island is divided between the sovereign states of East Timor on the eastern part and Indonesia on the western part. The Indonesian part, al ...

, Indonesia.

References

External links

World Register of Marine Species

Williams S.T., Smith L.M., Herbert D.G., Marshall B.A., Warén A., Kiel S., Dyal P., Linse K., Vilvens C. & Kano Y. (2013) ''Cenozoic climate change and diversification on the continental shelf and slope: evolution of gastropod diversity in the family Solariellidae (Trochoidea).'' Ecology and Evolution 3(4): 887–917
{{Commons category mutabile Gastropods described in 1908