Scaly-foot gastropod

Scaly-foot gastropod
Preserved specimen of Crysomallon squamiferum.
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Vetigastropoda
Superfamily:	Neomphaloidea
Family:	Peltospiridae
Genus:	Crysomallon
Species:	C. squamiferum
Binomial name
Crysomallon squamiferum Van Dover et al., 2001[1]

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.^[2]

Habitat

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.

Description

The snail's foot is armored with iron-mineral scales. It is protected by scale-shaped sclerites composed of the iron sulfides^[3] greigite and pyrite.^[4] 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.^[2]

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.^[5]

The United States military is currently funding research on the armor of the snail in hopes of developing insights into new military armor designs.^[5]

References

1. ^ Van Dover CL, Humphris SE, Fornari D, Cavanaugh CM, Collier R, Goffredi SK, Hashimoto J, Lilley MD, Reysenbach AL, Shank TM, Von Damm KL, Banta A, Gallant RM, Gotz D, Green D, Hall J, Harmer TL, Hurtado LA, Johnson P, McKiness ZP, Meredith C, Olson E, Pan IL, Turnipseed M, Won Y, Young CR 3rd, Vrijenhoek RC (2001). "Biogeography and ecological setting of Indian Ocean hydrothermal vents". Science 294 (5543): 818–23. doi:10.1126/science.1064574. PMID 11557843. http://www.sciencemag.org/cgi/content/abstract/294/5543/818. 
2. ^ ^{a b} Yao, H., Dao, M., Imholt, T., Huang, J., Wheeler, K., Suresh, S., and C. Ortiz (2010). "Protection Mechanisms Informed by the Unique Iron-Plated Armor of a Deep Sea Hydrothermal Vent Gastropod". PNAS. 
3. ^ Warén A, Bengtson S, Goffredi SK, Van Dover CL (2003). "A hot-vent gastropod with iron sulfide dermal sclerites". Science 302 (5647): 1007. doi:10.1126/science.1087696. PMID 14605361. http://www.scienceonline.org/cgi/content/full/302/5647/1007. 
4. ^ Pickrell, John (2003-11-07). "Armor-Plated Snail Discovered in Deep Sea". National Geographic News. http://news.nationalgeographic.com/news/2003/11/1107_031107_snailarmor.html. 
5. ^ ^{a b} "Snail's iron armour eyed by military". CBC News. 2010-01-19. http://www.cbc.ca/technology/story/2010/01/18/tech-biology-snail-shell.html. 

Further reading

• Goffredi SK, Warén A, Orphan VJ, Van Dover CL, Vrijenhoek RC (2004). "Novel forms of structural integration between microbes and a hydrothermal vent gastropod from the Indian Ocean". Appl Environ Microbiol 70 (5): 3082–90. doi:10.1128/AEM.70.5.3082-3090.2004. PMC 404406. PMID 15128570. http://aem.asm.org/cgi/content/full/70/5/3082. 
• Suzuki Y, Kopp RE, Kogure T, Suga A, Takai K, Tsuchida S, Ozaki N, Endo K, Hashimoto J, Kato Y, Mizota C, Hirata T, Chiba H, Nealson KH, Horikoshi K, Kirschvink JL (2006). "Sclerite formation in the hydrothermal-vent scaly-foot gastropod - possible control of iron sulfide biomineralization by the animal". Earth Planet Sci Lett 242: 39–50. doi:10.1016/j.epsl.2005.11.029. http://www.gps.caltech.edu/%7Ejkirschvink/pdfs/SuzukiGastropodGreigite.pdf. 

External links

• photo of Crysomallon squamiferum
• New Scaly-Foot Gastropod found in Indian Ocean; discovery of a white scaly-foot gastropod; 1 July 2011