Scaly-foot gastropod

Appearance

The shell is of a unique construction, with three layers. The outer layer consists 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 species is considered to be one of the most peculiar deep-sea hydrothermal-vent gastropods, and it is the only known extant animal that incorporates iron sulfide into its skeleton (into both its sclerites and into its shell as an exoskeleton).

Range and habitat

The scaly-foot gastropod is a vent-endemic gastropod known only from the deep-sea hydrothermal vents of the Indian Ocean, that are around 2,780 metres (1.73 mi) in depth. The species has subsequently also been found in the Solitaire field, 19°33.413′S 65°50.888′E, Central Indian Ridge, within the Exclusive Economic Zone of Mauritius and Longqi (means "Dragon flag" in Chinese) field, 37°47.027′S 49°38.963′E, Southwest Indian Ridge. Nakamura et al. Hypothesized that the occurrence of the scaly-foot gastropod in the Indian Ocean suggests a relationship of the hydrothermal vent faunas between these two areas.

Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.

Diet

Snails move on a single foot and feed with a rasping tongue. Island and spring species rarely recolonise once the site is emptied.

In crisis

This vent-endemic gastropod is known only from deep-sea hydrothermal vents in the Indian Ocean, where it has been found at depths of about 2,400–2,900 m (1.5–1.8 mi). In 2019, it was declared endangered on the IUCN Red List, the first species to be listed as such due to risks from deep-sea mining of its vent habitat. Its potential habitat across all Indian Ocean hydrothermal vent fields has been estimated to be at most 0.27 square kilometres (67 acres), while the three known sites at that it has been found, between that only negligible migration occurs, add up to 0.0177 square kilometres (4.4 acres), or less than one-fifth of a football field.

The population at the Longqi vent field may be of particular concern. Furthermore, by genetic measures the population at Longqi is poorly connected to those at the Kairei and Solitaire vent fields, over 2000 km away within the Central Indian Ridge.

Scaly-foot gastropod is Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.

Sources

Written for this catalog from the English Wikipedia article on Scaly-foot gastropod, Wikidata item Q5962358. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.