''Asthelys munda'' 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

Seguenziidae Seguenziidae is a family of very small deepwater sea snails, marine gastropod mollusks in the superfamily Seguenzioidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).Bouchet, P. (2012). Seguenziidae. Accessed through ...

. This species is spelled as ''Asthelys mundus'' in CLEMAM.CLEMAM: ''Asthelys mundus''
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Description

(Original description by Watson) The height of the shell attains 3.3 mm. The shell is broadly conical, flat on the base, and sharply angulated. It is small, thin, delicate, smooth, glossy, and nacreous under a thin white calcareous surface. Sculpture: There are longitudinals, which are very faint but still sharp, sinuated, showing the old lines of growth. There are over the whole surface very faint traces of spirals. At the bottom of each

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 ...

, about 0.25 mm. above the suture, is a sharp narrow thread, which on 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 bordered below by a second, rather higher and sharper, which forms the carina, and which on the spire is buried by the overlap of the succeeding whorl. On the base of the shell there are about eleven fine spirals, within which is a strong furrow, and a projecting, crenulated, or ropelike thread forming the edge of the umbilicus. The colour of the shell is opalescent, from the underlying

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 ...

shining through the polished, thin, translucent calcareous layer of the surface. The spire is high and conical. The apex is flattened, with the minute smooth embryonic 1½ whorl slightly projecting. The 6

s show a regular and slow increase (but the specimen is not full-grown). The spire is perfectly flat, the slope being scarcely broken by the suprasutural thread. The suture is linear, almost invisible. The aperture is perpendicular, irregularly rectangular, broader than high. The outer lip is sharp and thin, with a slight open sinus. It is sharply angled at the periphery, slightly arched across the base, apparently nicked at the point of the columella. The inner lip is arched, strengthened by a thin pad, reverted on the umbilicus so as to leave a groove behind it, with a slight tooth in front. From the body it bends very much over to the left, so as largely to cover the umbilicus. It then advances straight and is toothed in front. The umbilicus is small, oblique-edged, with a crenulated margin (described as ''Basilissa munda'').

Distribution

This marine species occurs in European waters off the Canary Islands.

References

* Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). ''European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification''. Collection Patrimoines Naturels, 50: pp. 180–213

External links

Serge GOFAS, Ángel A. LUQUE, Joan Daniel OLIVER,José TEMPLADO & Alberto SERRA (2021) - The Mollusca of Galicia Bank (NE Atlantic Ocean); European Journal of Taxonomy 785: 1–114

Natural History Museum, London (NHM): Collections Management Database System
{{Taxonbar, from=Q3172926 munda Gastropods described in 1879