Saturday, April 9, 2011
April 9, 2011 : Scaly-foot Gastropod
Crysomallon squamiferum, common name the scaly-foot gastropod, is a species of deep sea hydrothermal vent snail, a marine gastropod mollusk in the family Peltospiridae.
This species was discovered in 2001 on the bases of black smokers at the Kairei hydrothermal vent field, on the Central Indian Ridge, just north of the Rodrigues Triple Point and about 2,420 metres (7,940 ft) below the surface.
The snail's foot is armored with iron-mineral scales. It is protected by scale-shaped sclerites composed of the iron sulfides greigite and pyrite. 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 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, a thin protein coating found on other snail shells. The innermost layer is made of aragonite, 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.