''Lirabuccinum dirum'', commonly known as the dire whelk, the spindle shell or the spindle whelk, is a species of

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 in the family 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 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 in Alaska to Monterey Bay in central California. It is particularly common in British Columbia, Washington state and Oregon, 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 ...

s, worms 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 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