Scaly-foot gastropod
Encyclopedia
Crysomallon squamiferum, common name the scaly-foot gastropod, 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 deep sea hydrothermal vent 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...

, a 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 Peltospiridae
Peltospiridae
Peltospiridae is a small family of gastropods in the clade Vetigastropoda .This family has no subfamilies but contains two genera each with a single described species....

.

Habitat

This species was discovered in 2001 on the bases of black smokers at the Kairei hydrothermal vent
Hydrothermal vent
A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots. Hydrothermal vents exist because the earth is both...

 field, on the Central Indian Ridge
Central Indian Ridge
The Central Indian Ridge is a divergent tectonic plate boundary between the African Plate and the Indo-Australian Plate, traversing the western regions of the Indian Ocean...

, just north of the Rodrigues Triple Point
Rodrigues Triple Point
The Rodrigues Triple Point is a geologic triple junction in the southern Indian Ocean where three tectonic plates meet: the African Plate, the Indo-Australian Plate, and the Antarctic Plate...

 and about 2420 metres (7,939.6 ft) below the surface.

Description

The snail's foot is armored with iron-mineral scales. It is protected by scale-shaped sclerite
Sclerite
A sclerite is a hardened body part. The term is used in various branches of biology for various structures including hardened portions of sponges, but it is most commonly used for the hardened portions of arthropod exoskeletons....

s composed of the iron sulfides greigite
Greigite
Greigite is an iron sulfide mineral with formula Fe3S4. It is the sulfur equivalent of the iron oxide magnetite . It was first described in 1964 for an occurrence in San Bernardino County, California, and named after the mineralogist and physical chemist Joseph W...

 and pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...

. No other animal is known to use iron sulfides in this way.

The snail's shell is unusual in that its structure is composed of three layers. The outer layer is made of the aforementioned iron sulfides, containing greigite
Greigite
Greigite is an iron sulfide mineral with formula Fe3S4. It is the sulfur equivalent of the iron oxide magnetite . It was first described in 1964 for an occurrence in San Bernardino County, California, and named after the mineralogist and physical chemist Joseph W...

 Fe3S4 about 30 μm thick. This makes this gastropod the only metazoan, known so far, to employ this material in its skeleton. The middle layer is organic, and is also the thickest of the three (about 150 μm). It is comparable to the periostracum
Periostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...

, a thin protein coating found on other snail shells. The innermost layer is made of aragonite
Aragonite
Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...

, a calcium mineral that is found in the shells of mollusks and various corals.

Each layer contributes to the effectiveness of the snail's shell in different ways. The middle organic layer appears to absorb the mechanical strain and energy generated by a squeezing attack (as by the claws of a crab), making the shell much tougher. The organic layer also acts to dissipate heat.

The United States military is currently funding research on the armor of the snail in hopes of developing insights into new military armor designs.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK