The scaly-foot gastropod, also known as the scaly-foot snail, sea pangolin, or volcano snail, is a unique species of deep-sea hydrothermal-vent snail that has captured the attention of scientists and marine enthusiasts alike. This vent-endemic gastropod is found only in the Indian Ocean, where it thrives in the extreme conditions of deep-sea hydrothermal vents at depths of about 2,400-2,900 m (1.5-1.8 mi).
One of the most distinctive features of the scaly-foot gastropod is its shell. Unlike other gastropods found in the deep sea, the shell of the scaly-foot gastropod is constructed with three layers. The outer layer is made of iron sulphides, the middle layer is equivalent to the organic periostracum found in other gastropods, and the innermost layer is made of aragonite. This unique shell construction gives the scaly-foot gastropod a distinctive appearance and makes it one of the most visually striking creatures found in the deep sea.
Another fascinating feature of the scaly-foot gastropod is its foot, which is armored at the sides with iron-mineralized sclerites. This armor provides protection against predators and may also help the snail navigate the rugged terrain around hydrothermal vents. Additionally, the snail's oesophageal gland houses symbiotic gammaproteobacteria from which it obtains its nourishment. This feature allows the snail to survive in the harsh conditions of the deep sea where food is scarce.
Perhaps the most remarkable aspect of the scaly-foot gastropod is its ability to incorporate iron sulfide into its skeleton. The snail is the only known extant animal that does this, using iron sulfide to create both its sclerites and its shell as an exoskeleton. This adaptation allows the snail to withstand the high temperatures and chemical concentrations found in the vicinity of hydrothermal vents.
Despite its fascinating features, the scaly-foot gastropod is at risk of extinction. In 2019, it was declared endangered on the IUCN Red List, making it the first species to be listed as such due to the risks posed by deep-sea mining of its vent habitat. As deep-sea mining becomes more prevalent, it is important to recognize the potential impact it could have on this unique and remarkable species.
In conclusion, the scaly-foot gastropod is a remarkable creature that showcases the incredible adaptability of life in the deep sea. Its unique shell, armored foot, and ability to incorporate iron sulfide into its skeleton make it one of the most distinctive species found in the deep sea. As we continue to explore and exploit the deep sea, it is important to recognize the potential impact our actions could have on this and other unique species.