''Oxystele merula'' 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 ...

mollusk in the family Trochidae, the top snails.Bouchet, P. (2013). Oxystele merula (Dillwyn, 1817). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=739283 on 12 February 2014

Description

The height of the shell varies between 27 mm and 40 mm, its diameter between 35 mm and 41 mm. The rather depressed conoidal shell is imperforate. Its color is lusterless purplish-black. The conical spire has an eroded yellowish apex. The following

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 floral ...

is spirally striate. The last two whorls are smooth. The six whorls are convex. The sutures are distinct. The

body whorl The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the b ...

is not carinated at the periphery, rather flattened on the base, and usually slightly eroded in front of the aperture. The large aperture is oblique. The outer lip has a black margin and is within silvery. The

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 ...

is smooth, but apparently lirate. The thin, white columella is arcuate and simple. The umbilico-columellar region is surrounded by a beautiful rose-colored tract. Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
(described as ''Monodonta merula'')

Distribution

This marine species occurs in the Atlantic Ocean off Angola, Namibia and the Cape Region, South Africa.

References

''Contributions to the knowledge of South African marine Mollusca''; Annals of The South African Museum vol. 47; 1963

External links

G.B. Sowerby (1892), ''Marine shells of South Africa: a catalogue of all the known species''

AJH Goodwin; ''Archaeology of the Oakhurst Shelter, George: Part VI. Stratified Deposits and Contents''; Transactions of the Royal Society of South Africa, 1937
{{DEFAULTSORT:Oxystele Merula merula Gastropods described in 1817