''Lirabuccinum dirum'', commonly known as the dire whelk, the spindle shell or the spindle 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 ...

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 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 Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Buccinidae, the true whelks. It used to be known as ''Searlesia dira'' and ''Buccinum dirum'' before being transferred to the genus '' Lirabuccinum''.

Taxonomy and nomenclature

The dire whelk was first described by

Lovell Augustus Reeve Lovell Augustus Reeve (19 April 1814 – 18 November 1865) was an English conchologist and publisher. Life Born at Ludgate Hill, London, on 19 April 1814, he was a son of Thomas Reeve, draper and mercer, by his wife Fanny Lovell. After attendi ...

in 1846 as ''Buccinum dirum''. In the early 20th century, William Healey Dall would come to the conclusion that the species belong to a genus up until then known only from the Atlantic fossil record, '' Searlesia''. This remained the status quo for most of the century, with more living species from both the Atlantic and Pacific added to ''Searlesia'' until 1991, when

Geerat J. Vermeij Geerat J. Vermeij is a Dutch-born paleoecologist and evolutionary biologist in the Department of Earth and Planetary Sciences at the University of California, Davis. He studies marine molluscs both as fossils and as living creatures. He received ...

split the Pacific species into a separate genus '' Lirabuccinum'' with ''B. dirum'' as its type.

Description

''L. dirum'' is a medium-sized, elongated whelk with a strong heavy shell, growing to a length of . There are four or five whorls separated by shallow grooves, and several rounded axial ribs, mainly on the spire. The first whorl of the shell (and the second whorl in young individuals) is sculptured with many narrow, evenly-spaced spiral ridges, which are also visible on the inside of the outer margin of the aperture. The aperture is an elongated oval-shape and can be closed with a horny operculum. There is a short

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 is ...

to accommodate the

siphon A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in a ...

, and a polished columella with no folds. This snail is usually grey or brownish-grey, but is occasionally orangish.

Distribution and habitat

This whelk is found in shallow waters in the northeastern Pacific Ocean. Its range extends from the

Chirikof Island Chirikof Island (russian: Остров Чирикова) is located in the Gulf of Alaska approximately southwest of Kodiak Island. Terrain Chirikof Island consists of of grasses and sedges. Treeless, it lies west of the western tree line in Al ...

in Alaska to Monterey Bay in central California. It is particularly common in

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

Washington state Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washington ...

and

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

, but uncommon in California. It is found intertidally on rocky shores and in the shallow subtidal zone, and is found down to about on the Cobb Seamount. As well as occurring on rocks, it is sometimes found on gravel or mud close to the foot of rocks in bays.

Ecology

''L. dirum'' is a predator and scavenger. It feeds on winkles,

limpet Limpets are a group of aquatic snails that exhibit a conical shell shape (patelliform) and a strong, muscular foot. Limpets are members of the class Gastropoda, but are polyphyletic, meaning the various groups called "limpets" descended indep ...

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

barnacle A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in eros ...

chiton Chitons () are marine molluscs of varying size in the class Polyplacophora (), formerly known as Amphineura. About 940 extant and 430 fossil species are recognized. They are also sometimes known as gumboots or sea cradles or coat-of-mail s ...

worm Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always). Worms vary in size from microscopic to over in length for marine polychaete wor ...

s and other invertebrates. It seems to specialise on dead or injured prey, and does not seem able to drill into intact shells in the way that many whelks do. When living intertidally it is subject to variations in salinity, and is particularly tolerant of low salinities. In fact it seeks out low salinity environments where other less tolerant organisms are stressed. It also consumes

carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures, c ...

, and extends its

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. In vertebrates, a proboscis is an elong ...

to feed on

tubeworm A tubeworm is any worm-like sessile invertebrate that anchors its tail to an underwater surface and secretes around its body a mineral tube, into which it can withdraw its entire body. Tubeworms are found among the following taxa: * Annelida, the ...

s inside their tubes or to share the prey being digested by the everted stomach of the ochre sea star.

Taxonomy and nomenclature

Description

Distribution and habitat

Ecology

References

Further reading