Armored snail

Given that hydrothermal vents—geysers on the deep ocean floor emitting mineral compounds that support a thriving ecosystem—were only discovered in 1977, it is perhaps unsurprising that novel organisms showing unique environmental adaptations are regularly reported from expeditions to these areas. In the November 7 Science, Anders Warén and colleagues at the Swedish Museum of Natural History report a gastropod mollusk from black-smoker chimneys in the Indian Ocean with its soft foot covered by a chain mail of imbricating scale-shaped iron sclerites (Science, 302:1007, November 7, 2003).

The so-far unnamed snail lives a sedentary life at the base of the black smokers—the hottest of the oceanic vents that spew mostly iron and dissolved sulfides, which combine to form iron sulfides. These compounds give the smoker its color and also provide the ingredients for the armored boot of the snail. The main component of the scales is...