animalworld:

SCALY FOOD GASTROPOD
Crysomallon squamiferum
© JAMSTEC

The first scaly-foot gastropod, Crysomallon squamiferum, was found in 2000 at the bases of black smokers at the Kairei hydrothermal vent field, on the Central Indian Ridge. In contrast to the approximately 2 °C/32 °F ambient water temperature at these depths, water emerges from these vents at temperatures ranging from 60 °C/140 °F up to as high as 464 °C/867 °F.

The snail thriving in these extreme conditions continues to attract deep-sea fan especially with its black, iron-fortified shell and operculum. 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.

Last December a team from JAMSTEC (Japan Agency for Marine-Earth Science and Technology) reported the discovery of a similar white scaly-foot gastropod also in the Indian Ocean.

They found white scaly-foot gastropod during an investigation of habitats at newly found hydrothermal vents in November 2010. Several aggregations of white scaly-foot gastropods were found at the sites. However the white scaly-foot gastropod does not assimilate iron sulfide. The physiological details have not yet been revealed so the questions remain: Are they same species? How did they evolved? Why do black scaly-foots need iron scales? Source and Source

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