''Bullia digitalis'', the finger plough shell or plough snail, 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 ...

Nassariidae The Nassariidae, Nassa mud snails (USA), or dog whelks (UK), are a taxonomic family of small to medium-sized sea snails, marine gastropod mollusks in the clade Neogastropoda. "Dog whelk" also refers to ''Nucella lapillus''. Shell description T ...

, the Nassa mud snails or dog whelks. These dominant scavengers are attracted by the scent of decaying animal matter from a considerable distance so that they converge from all directions to feed.

Description

Length: 60 mm Narrow, smooth shell with a long, pointed spire, usually light yellow or creamy, often tinged with violet or yellow. The large, oval foot is offwhite. The operculum has serrated margins. Bullia digitalis - Animation small

The ovate shell is elongated, subturreted, smooth and polished. It is of a reddish yellow color. The shell is composed of seven

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). Whorls in nature File:Photograph and axial plane floral ...

s, hardly convex. The suture which separates them is simple, shallow and submargined. The

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics), a teenaged super villainess in the Marvel Universe * Ape-X, a super-intelligent ape in the Squadron Supreme universe *Apex ...

is moderately pointed. Pretty prominent striae of growth are seen upon the lowest whorl. The ovate

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...

is smooth, widened at the middle and strongly emarginated at its base. The

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the wo ...

is yellowish, smooth and arched. A keel, continues from the upper third of the aperture to the base of the outer

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

. The space between the keel and the edge of the lip is filled with oblique folds. The outer lip is simple, thin, sharp, and slightly effuse towards the middle.Kiener (1840). General species and iconography of recent shells : comprising the Massena Museum, the collection of Lamarck, the collection of the Museum of Natural History, and the recent discoveries of travellers; Boston :W.D. Ticknor,1837
(described as ''Buccinum achatinum'')

Distribution

Lower east, south, south-west and west coast of

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

. Best viewing:

Kei Mouth Kei Mouth (Afrikaans: ''Keimond'') is a resort town on the southeast coast of South Africa, situated in the Wild Coast region of the Eastern Cape Province, situated 94 kilometres from the city of East London. The town is situated on the Indian ...

Status

Common to locally very common; the dominant plough shell on

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

shores.

Habitat

Sandy beaches along the surf zone, low on the shore from middle tidal zone seawards where the sand is not too coarse.

Behaviour

When the tide starts to rise, this snail emerges from the sand, spreads its large "foot" like a sail, and surfs up the beach in response to the smell of carrion. The large foot is also used to burrow into the sand when the tide recedes. Sticks its proboscis into the prey to suck up soft tissues. Often gathers in large numbers to feed on dead and stranded

jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...

and bluebottles.

Similar species

Various plough shells on the southern African coast look similar, including ''

Bullia rhodostoma ''Bullia rhodostoma'', common name the smooth plough shell, is a species of sea snail, a marine gastropod mollusk in the family Nassariidae, the nassa mud snails or dog whelks. Description The length of the shell varies between 25 mm and 5 ...

'' on the south coast and ''

Bullia natalensis ''Bullia natalensis'', the pleated plough shell, is a species of sea snail, a marine gastropod mollusk in the family Nassariidae, the Nassa mud snails or dog whelks. Description The length of the shell varies between 20 mm and 60 mm. ...

'' (pleated plough shell) on the coast of

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN and known as "the garden province") is a province of South Africa that was created in 1994 when the Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu) and Natal Province were merged. It is locate ...

. ''B. digitalis'' however does not have pleated whorls like the pleated plough shell. All the common plough shells on the coast can only de differentiated for each other by their colour.

References

External links

{{Taxonbar, from=Q3643336 Nassariidae Gastropods described in 1817 Articles containing video clips