''Phorcus lineatus'', common name the lined top shell, 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 ...

Trochidae The Trochidae, common name top-snails or top-shells, are a family of various sized sea snails, marine gastropod molluscs in the subclass Vetigastropoda. This family is commonly known as the top-snails because in many species the shell resembles ...

, the top snails.Gofas, S. (2012). ''Phorcus lineatus'' (da Costa, 1778). Accessed 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=689176 on 2012-11-23 It is native to shores of the eastern North Atlantic Ocean.

Description

The size of the shell varies between 10 mm and 35 mm. The very thick and solid imperforate shell is subperforate in the young. It has a globose-conic shape. It is dull grayish, densely marked all over with very numerous fine flexuous or zigzag braided purplish-black lines. 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 conic. The 6 to 7

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 convex. The

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics) A-Bomb Abomination Absorbing Man Abraxas Abyss Abyss is the name of two characters appearing in Ameri ...

is usually eroded and orange-colored. 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 flattened around the superior portion. The base of the shell is eroded in front of 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 ...

. The aperture is oblique. The

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 short, obtusely subdentate near the base, spreading at the insertion into a heavy callous, which covers the

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

. This species is similar to ''

Phorcus turbinatus ''Phorcus turbinatus'', common name the turbinate monodont, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.Gofas, S. (2012). ''Phorcus turbinatus'' (Born, 1780). Accessed through: World Register of ...

'' in form, but usually has the outlines of the spire more convex. The columella projection or tooth is nearer the base than in the ''Phorcus turbinatus'', and the diverse color patterns will serve to further distinguish the two species.Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
(described as ''Monodonta crassa'') Patella lusitanica-Mytilus edulis-Monodonta lineata-Balanus balanoides

Patella lusitanica-Mytilus edulis-Monodonta lineata-Balanus balanoides

Distribution

This species occurs in the following locations: * European waters ( ERMS scope) * Portuguese Exclusive Economic Zone * Spanish Exclusive Economic Zone * United Kingdom Exclusive Economic Zone * Wimereux * Atlantic Ocean off

Mauritania Mauritania, officially the Islamic Republic of Mauritania, is a sovereign country in Maghreb, Northwest Africa. It is bordered by the Atlantic Ocean to the west, Western Sahara to Mauritania–Western Sahara border, the north and northwest, ...

References

External links

World Register of Marine Species
* {{Taxonbar, from=Q7187373 lineatus Gastropods described in 1778 Gastropods of Africa Gastropods of Europe Taxa named by Emanuel Mendes da Costa