''Vaceuchelus semilugubris'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

, a marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Chilodontaidae Chilodontaidae is a taxonomic family of mostly small deepwater sea snails, marine gastropod molluscs in the clade Vetigastropoda (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). Taxonomy The family was previously in ...

.Bouchet, P. (2012). ''Vaceuchelus semilugubris'' (Deshayes, 1863). Retrieved through:

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive catalogue and list of names of marine organisms. Content The content of the registry is edited and maintained by scien ...

at http://www.marinespecies.org/aphia.php?p=taxdetails&id=547174 on 2013-04-14

Description

The height of the shell attains 3.5 mm. The small shell has a turbinate, subglobose shape. Its color is white, marbled with black. The

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spire ...

is somewhat obtuse. The five

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). In nature File:Photograph and axial plane floral diagra ...

s are declivous above and spirally deeply sulcate. The sulci are subgranulose. The

body whorl The body whorl is part of the morphology (biology), morphology of the gastropod shell, 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 ...

is large with a perforate base. The very oblique

aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

is circular and pearly within. The flat

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

is arcuate and truncate anteriorly.G.W. Tryon (1888), Manual of Conchology X; Academy of Natural Sciences, Philadelphia
(described as ''Leptothyra semilugubris'')

Distribution

This marine shell occurs in the Indian Ocean off

Réunion Réunion (; ; ; known as before 1848) is an island in the Indian Ocean that is an overseas departments and regions of France, overseas department and region of France. Part of the Mascarene Islands, it is located approximately east of the isl ...

and

Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...

References

External links

Deshayes, G. P. (1863). Catalogue des mollusques de l'île de la Réunion (Bourbon). Pp. 1-144. In Maillard, L. (Ed.) Notes sur l'Ile de la Réunion. Dentu, Paris.

Encyclopedia of Life

Herbert, D. G. (2012). A Revision of the Chilodontidae (Gastropoda: Vetigastropoda: Seguenzioidea) of Southern Africa and the South-Western Indian Ocean. African Invertebrates. 53(2): 381-502

World Register of Marine Species
* {{Taxonbar, from=Q14512408 semilugubris Gastropods described in 1863