Bolinus brandaris and commonly known as the purple dye murex or the spiny dye-murex, is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of medium-sized predatory sea snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

, an edible marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusk in the family Muricidae

Muricidae

Muricidae, common name murex snails or rock snails, is a large and varied taxonomic family of small to large predatory sea snails. With approximately 1,600 living species the Muricidae represent almost 10% of the Neogastropoda. Additionally, 1,200 fossil species have been recognised...

, the murex snails or the rock snails.

Distribution

This snail lives in the central and western parts of the Mediterranean Sea

Mediterranean Sea

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

 and has been found on isolated coral atoll beaches in the Indian Ocean and South China Sea. It was known since ancient times as a source for purple

Purple

Purple is a range of hues of color occurring between red and blue, and is classified as a secondary color as the colors are required to create the shade....

 dye and also as a popular food source under various names, among which sconciglio, from which comes the word scungilli.

Habitat

This species lives on rocks in shallow water.

Shell description

The shell is usually golden-brown in color with a very long siphonal canal

Siphonal canal

Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. In many carnivorous snails, where the siphon is particularly long, the structure...

 and a rounded body whorl

Body whorl

Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...

 with a low spire

Spire (mollusc)

A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...

. There are a row of spines corresponding to the end of each growth stage.

The adult shell size of this species is about 60 to 90 mm.

Human use

This species, like many other species in the family Muricidae, can produce a secretion which is milky and without color when fresh but which turns into a powerful and lasting dye when exposed to the air.

This was the mollusc species used by the ancients to produce Tyrian purple

Tyrian purple

Tyrian purple , also known as royal purple, imperial purple or imperial dye, is a purple-red natural dye, which is extracted from sea snails, and which was possibly first produced by the ancient Phoenicians...

 fabric dye.

Sea snails of the species Banded dye-murex Hexaplex trunculus

Hexaplex trunculus

Hexaplex trunculus is a medium-sized species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex shells or rock snails....

were also used to produce a purple-blue or indigo dye

Indigo dye

Indigo dye is an organic compound with a distinctive blue color . Historically, indigo was a natural dye extracted from plants, and this process was important economically because blue dyes were once rare. Nearly all indigo dye produced today — several thousand tons each year — is synthetic...

. In both cases the mollusks secrete the dye in mucus from their hypobranchial glands.

It is a cannibalistic species. Intensive breeding in ancient Minoan civilizations revealed shells were pierced by fellow individuals possibly due to the high density of population in breeding tanks.

Further reading

• Radwin, G. E. & D'Attilio A. (1986). Murex shells of the world. An illustrated guide to the Muricidae. Stanford Univ. Press, Stanford, x + pp. 1-284 incl 192 figs. + 32 pls.