''Nucella lamellosa'', commonly known as the frilled dogwinkle or wrinkled purple whelk, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of sea snail, a marine gastropod

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Muricidae Muricidae is a large and varied taxonomic family of small to large predatory sea snails, marine gastropod mollusks, commonly known as murex snails or rock snails. With about 1,600 living species, the Muricidae represent almost 10% of the Neoga ...

, the murex snails or rock snails. This species occurs in the eastern Pacific Ocean, its range extending in the intertidal zone from the Aleutian Islands southward to central California.

Description

''Nucella lamellosa'' is a large snail with a strong shell growing to a length of and width of . The shell has no more than seven whorls and has a horny operculum. The spire is well developed, with a short notch to accommodate the siphon. This snail is rather variable in colour, shape and surface texture. Some specimens are smooth, others rough and others have frilled

lamellae Lamella (plural lamellae) means a small plate or flake in Latin, and in English may refer to: Biology * Lamella (mycology), a papery rib beneath a mushroom cap * Lamella (botany) * Lamella (surface anatomy), a plate-like structure in an animal * ...

(angular plates). Some of these features may be as a result of abrasion and wave action, and when present, the spiral sculpture takes the form of one or two ridges per whorl, the whorls being flattened near their joints making them appear to be angled. This snail can be white, grey, brown or orange, occasionally purplish, and is sometimes spirally banded.

Distribution

This whelk is found in shallow waters in the eastern Pacific Ocean. Its range extends from the Bering Strait and the

Aleutian Islands The Aleutian Islands (; ; ale, Unangam Tanangin,”Land of the Aleuts", possibly from Chukchi ''aliat'', "island"), also called the Aleut Islands or Aleutic Islands and known before 1867 as the Catherine Archipelago, are a chain of 14 large v ...

to central California. It is found intertidally on rocks from the mid to lower shore and is one of the commonest whelks in this habitat in the Pacific Northwest.

Ecology

This whelk is a

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

, feeding largely on mussels and barnacles. The radula is used to scrape through the shell of the prey and the soft tissue is extracted. The whelk is itself eaten by crabs such as the red rock crab '' Cancer productus'' and the seastar '' Pisaster ochraceus''. In the presence of the crabs, there is a tendency for the whelk's shell to grow thicker and be more robust, and thus less easy for the crab to crush. This may be as a result of chemicals released into the water by the crabs because the thickness of the whelk's shell seems unaffected by the presence of ''

Carcinus maenas ''Carcinus maenas'' is a common littoral crab. It is known by different names around the world. In the British Isles, it is generally referred to as the shore crab, or green shore crab. In North America and South Africa, it bears the name europ ...

'', a recently introduced invasive species of crab that also feeds on whelks. A different response in shell morphology was evinced in the presence of the seastar. Here, the shell tended to get longer with a high spire, enabling the whelk to retract its soft tissues as far as possible from the seastar. If both crabs and seastars were present, the shell phenotype that tended to evolve reflected the response to the predator that caused the greatest mortality. The whelks also show behavioural responses to both crabs and seastars by seeking refuge. Breeding takes place in hidden locations such as under rocks, with many whelks congregating to mate and lay eggs in capsules which resemble clusters of

oat The oat (''Avena sativa''), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural, unlike other cereals and pseudocereals). While oats are suitable for human con ...

s as they dangle from the substrate.

References

{{DEFAULTSORT:Nucella lamellosa Muricidae Gastropods described in 1791 Taxa named by Johann Friedrich Gmelin