''Tritia recidiva'' 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 ...

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

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 ...

Nassariidae The Nassariidae, Nassa mud snails (US), or dog whelks (UK) are a taxonomic family of small to medium-sized snails, mostly marine gastropod mollusks in the clade Neogastropoda. These snails have rounded shells with a high spire, an oval ap ...

, the nassa mud snails or dog whelks.

Description

The shell grows to a length of 12 mm. It has a high, slightly cyrtoconoid (almost with the shape of a cone, but having convex sides)

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 ...

and a somewhat constricted

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 ...

. The

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called " ...

consists of three rather large and smooth

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. The first three

teleoconch The gastropod shell is part of the body of many gastropods, including snails, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium ...

whorls contain spiral cords and axial folds, which fade out on the next two except for the subsutural spirals. The body whorl resumes a spiral

sculpture Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...

of very even, flattened cords much that are broader than the interspaces. The

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 lanceolate. The outer lip is slightly thickened externally and bears five or six strong rounded denticles inside. The parietal callus is appressed and devoid of a parietal denticle. It continues into a

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 ...

r callus which has a rounded edge, slightly raised over the

siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water i ...

and bearing a few tubercles. The colour of the shell has a brown hue over a white background. The subsutural and median cords are articulated with darker brown. The aperture is white.

Distribution

''T. recidiva'' occurs in the Western Mediterranean Sea and in the Atlantic Ocean off

Madeira Madeira ( ; ), officially the Autonomous Region of Madeira (), is an autonomous Regions of Portugal, autonomous region of Portugal. It is an archipelago situated in the North Atlantic Ocean, in the region of Macaronesia, just under north of ...

References

* Adam W. & Glibert M. (1974). ''Contribution à la connaissance de Nassarius semistriatus (Brocchi, 1814). (Mollusca : Gastropoda).'' Bulletin de l'Institut Royal des Sciences Naturelles de Belgique 50(3): 1–78. * 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

Watson, R. B. (1897). On the marine Mollusca of Madeira; with descriptions of thirty-five new species, and an index-list of all the known sea-dwelling species of that island. Journal of the Linnean Society of London, Zoology. 26(19): 233-329, pl. 19-20

Pallary, P. (1900). Coquilles marines du littoral du département d'Oran. Journal de Conchyliologie. 48(3): 211-422

Dautzenberg, Ph. (1889). Contribution à la faune malacologique des Iles Açores. Résultats des Campagnes Scientifiques Accomplies sur son Yacht par Albert Ier Prince Souverain de Monaco, I. Imprimerie de Monaco: Monaco. 112, IV plates pp

Gofas, S.; Luque, Á. A.; Templado, J.; Salas, C. (2017). A national checklist of marine Mollusca in Spanish waters. Scientia Marina. 81(2) : 241-254, and supplementary online materia
* {{DEFAULTSORT:Tritia Recidiva recidiva Gastropods described in 1876