Dr. Chong Chen, Japan
Info
The RRS James Cook JC67 expedition in 2011 investigated the biota of the Longqi hydrothermal field on the Southwest Indian Ridge for the first time and discovered a previously unknown population of “scaly snails.”
Chrysomallon squamiferum has a unique characteristic among gastropods: it has hundreds of hard skin sclerites on its foot.
These sclerites are curved, elongated, proteinaceous, non-calcified, and measure approximately 1 x 5 mm in adult animals.
The color of the sclerites ranges from white to metallic black, depending on the extent of iron sulfide coating, while newly grown sclerites are milky white.
The shell of the armored sea snail consists of three whorls, is spherical with an indented tip, and is tightly coiled.
The operculum is located in the metapodium, hidden under layers of sclerites, and is multiple spiral-shaped, concentric in young animals, and curved and bent in adults.
The large foot cannot be completely retracted into the shell and is red in living snails.
Chrysomallon squamiferum is considered an iconic species and ferrimagnetic species and has evolved to withstand a hostile environment, making it certainly no ordinary snail...
What is completely unique is that iron sulfide has also been found in the snail's shell, further enhancing the protection provided by its natural casing.
Nature has developed special adaptations to life and survival in such a toxic and harsh environment.
Chrysomallon squamiferum occurs exclusively in hydrothermal vents on deep-sea ridges in the Indian Ocean and is currently known from both active black smokers and diffuse flow areas at depths of 2400 meters to 2900 meters below sea level.
Populations of this species occur in hydrothermal vents several kilometers below sea level, surrounded by toxic chemicals and extremely high temperatures of over 300 °Celsius.
They obtain their food from endogenous bacteria that grow in a special pouch in their throat and convert the chemicals in the vents into energy.
The entire body and life cycle of the snails revolve around bacteria that grow in a special pouch in their throat. These convert chemicals that escape from the openings into energy, thus providing the snails with food. In order to feed their microbes well, the scale snails have developed huge gills with which they absorb oxygen and chemicals from the seawater and transport them via their bloodstream and an enormous heart.
See also: Endosymbiont theory.
Theories for the presence of the iron sulfide coating on the foot:
1.) Protection from predators such as predatory crabs?
2.) Protection of the otherwise soft foot against excessive ambient temperatures?
3.) Protection against toxic chemical cocktails from the different mineral compositions of the hydrothermal vents?
> In 2019, scientists discovered that the scales on the snails' feet do not serve to protect them from predators, but rather ward off a toxic danger that comes from within. The bacteria found in the throat of a scale foot snail release sulfur as a waste product, which is lethal to snails (it is a common active ingredient in snail pellets).
Etymology:
The genus name Chrysomallon comes from Greek and means “golden-haired” or “golden fleece,” referring to the metallic coating often found on the shell and sclerites of the snail, which contains pyrite, commonly known as fool's gold.
Etymology:
The species name “squamiferum” is Latin and means “scaly,” referring to the numerous hard sclerites that cover the foot (of the snail).
We would like to express our sincere thanks to Dr. Chong Chen, the lead author of the original description and a passionate deep-sea researcher of mollusks (including snails, mussels, octopuses, and chitons).
Dr. Chen is particularly interested in the diversity of organisms and their novelties, how they help organisms adapt to their environment, and how these novelties arise (and whether there are common laws that govern them).
We wish Dr. Chen many more wonderful discoveries like that of Chrysomallon squamiferum.
Chrysomallon squamiferum has a unique characteristic among gastropods: it has hundreds of hard skin sclerites on its foot.
These sclerites are curved, elongated, proteinaceous, non-calcified, and measure approximately 1 x 5 mm in adult animals.
The color of the sclerites ranges from white to metallic black, depending on the extent of iron sulfide coating, while newly grown sclerites are milky white.
The shell of the armored sea snail consists of three whorls, is spherical with an indented tip, and is tightly coiled.
The operculum is located in the metapodium, hidden under layers of sclerites, and is multiple spiral-shaped, concentric in young animals, and curved and bent in adults.
The large foot cannot be completely retracted into the shell and is red in living snails.
Chrysomallon squamiferum is considered an iconic species and ferrimagnetic species and has evolved to withstand a hostile environment, making it certainly no ordinary snail...
What is completely unique is that iron sulfide has also been found in the snail's shell, further enhancing the protection provided by its natural casing.
Nature has developed special adaptations to life and survival in such a toxic and harsh environment.
Chrysomallon squamiferum occurs exclusively in hydrothermal vents on deep-sea ridges in the Indian Ocean and is currently known from both active black smokers and diffuse flow areas at depths of 2400 meters to 2900 meters below sea level.
Populations of this species occur in hydrothermal vents several kilometers below sea level, surrounded by toxic chemicals and extremely high temperatures of over 300 °Celsius.
They obtain their food from endogenous bacteria that grow in a special pouch in their throat and convert the chemicals in the vents into energy.
The entire body and life cycle of the snails revolve around bacteria that grow in a special pouch in their throat. These convert chemicals that escape from the openings into energy, thus providing the snails with food. In order to feed their microbes well, the scale snails have developed huge gills with which they absorb oxygen and chemicals from the seawater and transport them via their bloodstream and an enormous heart.
See also: Endosymbiont theory.
Theories for the presence of the iron sulfide coating on the foot:
1.) Protection from predators such as predatory crabs?
2.) Protection of the otherwise soft foot against excessive ambient temperatures?
3.) Protection against toxic chemical cocktails from the different mineral compositions of the hydrothermal vents?
> In 2019, scientists discovered that the scales on the snails' feet do not serve to protect them from predators, but rather ward off a toxic danger that comes from within. The bacteria found in the throat of a scale foot snail release sulfur as a waste product, which is lethal to snails (it is a common active ingredient in snail pellets).
Etymology:
The genus name Chrysomallon comes from Greek and means “golden-haired” or “golden fleece,” referring to the metallic coating often found on the shell and sclerites of the snail, which contains pyrite, commonly known as fool's gold.
Etymology:
The species name “squamiferum” is Latin and means “scaly,” referring to the numerous hard sclerites that cover the foot (of the snail).
We would like to express our sincere thanks to Dr. Chong Chen, the lead author of the original description and a passionate deep-sea researcher of mollusks (including snails, mussels, octopuses, and chitons).
Dr. Chen is particularly interested in the diversity of organisms and their novelties, how they help organisms adapt to their environment, and how these novelties arise (and whether there are common laws that govern them).
We wish Dr. Chen many more wonderful discoveries like that of Chrysomallon squamiferum.
