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Scaly-foot SnailChrysomallon squamiferum

Every figure, record and mechanism on the Scaly-foot Snail profile was written from a source, and this is the working table behind it: 46 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

Animal Diversity Web, University of Michigan

Chrysomallon squamiferum. Animal Diversity Web, University of Michigan.

The page saysDeep-sea hydrothermal vent fields in the Indian Ocean (Kairei, Solitaire, Longqi and others), 2,400 to 2,900 meters down
The source saysVolcano Snails (Chrysomallon squamiferum) live in 3 different deep-sea hydrothermal vent fields, all located in the Indian Ocean ... Originally found in the Kairei vent field, and later found in the Solitaire and Longqi vent fields. ... Range depth 2400 to 2900 mNote: 'and others': endosymbiont-2022 (newer) samples five vent fields, claimed below
The page saysEnergy supplied by sulfur-oxidizing bacteria living inside its enlarged oesophageal gland
The source saysThey have a larger oesophageal gland that houses chemosynthetic bacteria, that provide energy to the snails.
The page sayslives at deep-sea hydrothermal vents on the floor of the Indian Ocean, 2,400 to 2,900 meters down, at vent fields including Kairei, Solitaire and Longqi
The source saysVolcano Snails (Chrysomallon squamiferum) live in 3 different deep-sea hydrothermal vent fields, all located in the Indian Ocean off the Eastern and Southern coasts of Madagascar. Originally found in the Kairei vent field, and later found in the Solitaire and Longqi vent fields. ... Range depth 2400 to 2900 m
The page saysIt measures 5 to 45 millimeters long, 32 millimeters on average.
The source saysRange length 5 to 45 mm ... Average length 32 mm
The page saysSnails at the iron-rich Kairei field are black and magnetic, because their armor contains a mineral called greigite.
The source saysthose in the Kairei vent field have a black color and are also magnetic because of the greigite presence
The page saysand are white
The source saysThose that live in the Solitaire vent field have a white color due to lack of iron
The page saysThe scaly-foot snail is what biologists call an obligate symbiotroph: it depends on its bacteria to survive.
The source saysVolcano snails are obligate symbiotrophs, meaning they need a symbiotic relationship to survive.
The page saysthe sulfur-oxidizing bacteria living inside it
The source saysThey have a larger oesophageal gland that houses chemosynthetic bacteria
The page saysThe sclerites and shell also defend it against predatory snails of the genus Phymorhynchus, which inject venom into their prey.
The source saysVolcano snails have their sclerites and protected shells to protect themselves from predators like the genus Phymorhynchus. They inject venom into their prey, so the volcano snail's protection prevents these attacks.

Source
02

Sun et al. 2020

Sun et al. (2020). The Scaly-foot Snail genome and implications for the origins of biomineralised armour. Nature Communications.

The page sayswhose foot scales and shell are often mineralised with iron sulfide
The source saysThe Scaly-foot Snail, Chrysomallon squamiferum , is unique among gastropod molluscs in having dense, imbricating chitinous sclerites covering the whole distal surface of the soft foot ... These hard parts, including sclerites and the shell, are often mineralised with iron sulfide
The page saysFoot scales and shell often mineralised with iron sulfide
The source saysThese hard parts, including sclerites and the shell, are often mineralised with iron sulfide
The page saysDensely packed, overlapping plates called sclerites cover its foot
The source saysThe Scaly-foot Snail, Chrysomallon squamiferum , is unique among gastropod molluscs in having dense, imbricating chitinous sclerites covering the whole distal surface of the soft foot
The page saysboth the sclerites and its shell are often mineralised with iron sulfide
The source saysThese hard parts, including sclerites and the shell, are often mineralised with iron sulfide
The page saysThat makes it the only known animal using iron as a significant part of its skeleton.
The source saysmaking it the only known metazoan using iron as a significant component of skeleton construction
The page saysiron-rich Kairei field
The source saysOn its discovery in the iron-rich Kairei hydrothermal vent field in the Indian Ocean in 2001
The page saysThe Solitaire field has about 1/58 of Kairei's iron, and the snails there lack the iron sulfide coating
The source saysa second population lacking iron sulfide mineralisation was discovered in the Solitaire hydrothermal site 11 characterised by low concentrations of iron (1/58 of that found at Kairei 12 )
The page saysThe living snail supplies sulfur through nano-scale, channel-like columns in its scales, and that sulfur reacts with iron diffusing in from the vent fluid to make iron sulfide nanoparticles.
The source saysthe Scaly-foot Snail mediates its scale biomineralisation by supplying sulfur through nano-scale channel-like columns in the scales, which reacts with iron ions diffusing inwards from the vent fluid to make iron sulfide nanoparticles
The page saysDense, overlapping scales cover its foot
The source saysThe Scaly-foot Snail, Chrysomallon squamiferum , is unique among gastropod molluscs in having dense, imbricating chitinous sclerites covering the whole distal surface of the soft foot
The page saysthey and its shell are often mineralised with iron sulfide
The source saysThese hard parts, including sclerites and the shell, are often mineralised with iron sulfide
The page saysbuilt from iron in the vent fluid around it
The source sayssupplying sulfur through nano-scale channel-like columns in the scales, which reacts with iron ions diffusing inwards from the vent fluid to make iron sulfide nanoparticles

Source
03

Okada et al. 2019

Okada et al. (2019). The making of natural iron sulfide nanoparticles in a hot vent snail. Proceedings of the National Academy of Sciences.

The page saysThe living snail supplies sulfur
The source saysthe living animal mediates biomineralization of iron sulfide nanoparticles via a channel-like columnar organic matrix that transports sulfur, which then reacts with iron ions diffusing in from the surrounding vent fluid

Source
04

Chen et al. 2015

Chen et al. (2015). The heart of a dragon: 3D anatomical reconstruction of the 'scaly-foot gastropod' (Mollusca: Gastropoda: Neomphalina) reveals its extraordinary circulatory system. Frontiers in Zoology.

The page sayswith a heart that takes up about 4% of its body volume
The source saysthe heart complex represents approximately 4 % of the body volume
The page saysand a heart that's about 4% of its body volume
The source saysthe heart complex represents approximately 4 % of the body volume
The page saysIts oesophageal gland is huge
The source saysthe body cavity is occupied by a huge oesophageal gland
The page saysEven its armor may serve the bacteria. The researchers who mapped its anatomy view its sclerites, its circulatory system and its high fecundity as adaptations that benefit its microbes.
The source saysall of its remarkable features—protective dermal sclerites, circulatory system, high fecundity—can be viewed as adaptations beneficial to its endosymbiont microbes
The page saysThose researchers infer that its elaborate circulatory system most likely evolved to oxygenate the bacteria in an oxygen-poor environment, or to supply them with hydrogen sulfide.
The source sayswe infer the elaborate cardiovascular system most likely evolved to oxygenate the endosymbionts in an oxygen poor environment and/or to supply hydrogen sulfide to the endosymbionts
The page saysIts auricle and ventricle together take up about 4% of its body volume.
The source saysBased on the volume of the auricle and ventricle, the heart complex represents approximately 4 % of the body volume.
The page saysThe same paper puts a healthy adult human's heart at around 1.3% of body volume: the snail's share is roughly three times bigger.
The source saysThe heart of Chrysomallon is estimated at 4 % of the body volume; by contrast the heart of a healthy human is averages at around 1.3 % of the body volume (mean total heart volume of adult humans 778 mlNote: the paper's own comparison, computed from its cited inputs (778 ml / 61.05 L = 1.27%); 4 / 1.3 = 3.1
The page saysIts muscular ventricle is thought to work by suction, drawing blood through the gill
The source saysWe interpret the heart, and particularly the muscular ventricle, functions to create suction that draws blood through the gillNote: ctenidium is the gastropod gill; the paper uses 'gill' itself here
The page saysthe giant heart mainly serves the gill and the gland full of bacteria
The source saysthe giant heart primarily serves the ctenidium and the oesophageal gland
The page saysA mouth on the underside of its snout opens into a buccal cavity holding a rhipidoglossate radula, a long toothed ribbon, though it has no jaws.
The source saysThe mouth opening on the ventral side of snout leads to buccal cavity contains a rhipidoglossate radula ... There are no jaws. ... The radula ribbon is long
The page saysPast the mouth its gut is small: a distinct stomach
The source saysthe digestive system apart from the oesophageal gland is relatively small and forms a simple loop (Fig. 5b ). The midgut is forms a clearly discernable stomach
The page saysthen an intestine reduced to a single loop, most likely because it relies on its bacteria for food
The source saysThe intestine however is reduced [ 17 ] and only has a single loop, unlike grazing peltospirids [ 25 , 26 ], most likely because of its nutritional reliance on endosymbiotic bacteria
The page saysIt has no eyes, and a detailed reconstruction of its anatomy found no sign of even a leftover optic nerve.
The source saysThere are no eyes and no evidence of even a remnant optic nerve emerging from the oesophageal nerve ring.
The page saysIts brain is a more or less solid lump of nerve tissue
The source saysThe brain is a more or less solid neural mass without clear structure or ganglia
The page sayswith a large nerve running out to each of its head tentacles
The source saysa large, prominent tentacular nerve projecting into the cephalic tentacles

Source
05

Lan et al. 2022

Lan et al. (2022). Endosymbiont population genomics sheds light on transmission mode, partner specificity, and stability of the scaly-foot snail holobiont. The ISME Journal.

The page saysand others
The source saysmultiple scaly-foot snail populations dwelling in five vent fields
The page sayssulfur-oxidizing bacteria
The source saysrelies on its sulphur-oxidising gammaproteobacterial endosymbionts for nutrition and energy
The page sayssupply the snail's nutrition and energy
The source saysrelies on its sulphur-oxidising gammaproteobacterial endosymbionts for nutrition and energy
The page saysFrom its surroundings, picked up afresh in each generation.
The source saysscaly-foot snails acquire endosymbionts through horizontal transmission from the environment at each generation
The page saysComparing the snail's own DNA against its bacteria's DNA shows mismatched family trees between hosts and symbionts across five vent fields, meaning the hosts are not simply inheriting a ready-made colony from a parent.
The source saysResults of population genomics analyses reveal an incongruent phylogeny between the endosymbiont and mitochondrial genomes of the scaly-foot snails in the five vent fields sampled, indicating that the hosts obtain endosymbionts via horizontal transmission in each generation.
The page saysMany of the symbiont populations are genetically very alike, though, and that leaves open the chance of a parent passing some along too.
The source saysthe genetic homogeneity of many symbiont populations implies that vertical transmission cannot be ruled out either

Source
06

Sigwart, J. 2017

Sigwart, J. (2017). Deep-sea conservation and the 'scaly-foot gastropod'. Tentacle: The Newsletter of the IUCN/SSC Mollusc Specialist Group.

The page saysAssuming the snail could live anywhere within any vent site in the Indian Ocean, a generous estimate puts its total potential habitat at around 0.27 square kilometers.
The source saysan assumption that the scaly-foot could potentially live anywhere within any vent site in this ocean basin, provides a generous estimate of total global potential habitat for the scaly-foot gastropod of around 0.27 km 2
The page saysIn 2017, both of its high-seas sites lay under licenses for mining exploration, which could reasonably be expected to shrink that habitat further.
The source saysTentacle No. 25—February 2017 ... Its two high seas localities are under license for mining exploration, which could reasonably be projected to lead to further reduction in habitat.Note: dated to the source (Tentacle No. 25, February 2017) rather than stated as a current state

Source
07

Sigwart, Chen & Thomas 2019

Sigwart, Chen & Thomas (2019). Chrysomallon squamiferum. The IUCN Red List of Threatened Species 2019: e.T103636217A103636261.

The page saysThe IUCN Red List assesses the scaly-foot snail as Endangered
The source saysIUCN Red List category: Endangered (EN).

Source
08

Lambert 2019

Lambert (2019). Ocean snail is first animal to be officially endangered by deep-sea mining. Nature.

The page saysin 2019 it became the first deep-sea animal declared endangered because of the threat of mining
The source says22 July 2019 Ocean snail is first animal to be officially endangered by deep-sea mining ... has become the first deep-sea animal to be declared endangered because of the threat of mining.Note: Nature news dated 22 July 2019; hand-cached (paywalled page, lede only)

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.