''Turritella communis'',

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contra ...

the "common tower shell" is a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

of medium-sized sea snails with an operculum,

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

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 es ...

s in the family

Turritellidae Turritellidae, common name the "tower shells" or "tower snails", is a taxonomic family of small to medium-sized sea snails, marine gastropod molluscs in the clade Sorbeoconcha. These snails are filter feeders. This method of feeding is somewhat ...

Distribution and habitat

This species occurs in the Eastern

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

from the

Lofoten Lofoten () is an archipelago and a traditional district in the county of Nordland, Norway. Lofoten has distinctive scenery with dramatic mountains and peaks, open sea and sheltered bays, beaches and untouched lands. There are two towns, Svolv� ...

Isles south to the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

and North Africa. It is rare or absent from the eastern

English Channel The English Channel, "The Sleeve"; nrf, la Maunche, "The Sleeve" ( Cotentinais) or (Jèrriais), ( Guernésiais), "The Channel"; br, Mor Breizh, "Sea of Brittany"; cy, Môr Udd, "Lord's Sea"; kw, Mor Bretannek, "British Sea"; nl, Het Kan ...

and the southern

North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian S ...

. This tower shell can be found in the

sublittoral zone The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminated ...

to depths up to 200 m, where it is usually found burrowed in gravelly mud at an angle of about 10°. There it remains stationary for long periods. It can be locally abundant on muddy sediment in shallow waters.

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

and subfossil shells of ''Turritella communis'' have been found in

interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene ...

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...

in the North Sea, from the

Late Pliocene Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effe ...

to the Quaternary Period.

Description

The tall, conical shell is brownish-yellow to white. It is sharply pointed and contains 16-20 enlarged whorls. The spiral ridges are numerous (with 3 - 6 more prominent) and may have a beaded appearance. The shell grows to a length of 3 cm and may become 1 cm wide. The angulate shell

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 ...

is small. The outer lip is crenulate. There is no

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

. The concave operculum is small and circular and has numerous pinnate bristles on its edges. The snail shows white markings on the tentacles, siphon and foot. This small foot shows dark spots and streaks.

Feeding habits

''Turritella communis'' feeds on deposits through ciliary feeding. In order to prevent larger particles entering the mantle cavity, it possesses at the mantle edge a curtain of tentacles of which the larger ones are pinnate.

References

*
Michelle Carter 2008. Turritella communis. An auger shell. Marine Life Information Network

Distribution and habitat

Description

Feeding habits

References

Further reading