🧲🐌 The Iron Snail 🧲🐌

As you know I love sharing strange or even alien looking creatures on my blog.

Well, this one has pretty much normal looks. But it really stands out for being the only extant animal we know of that uses iron in the form of iron sulfide into its skeleton!

Meet Chrysomallon squamiferum, commonly known as scaly-foot gastropod, scaly-foot snail, sea pangolin. Oh, it has an even more badass and imo fitting nickname. The volcano snail!

source

But why volcano snake?

Simple. It likes heat. A lot! It lives several miles below the ocean surface on hydrothermal vents at depths of about 2.5 km. This environment isn't only super hot at temperatures often over 300C but also full of toxic chemicals lethal for most organisms.

Talk about a bad ass! These temperatures would kill almost all single celled organisms, let alone multicellular ones.

As aforementioned, this is the only known animal whose body is largely comprised of mineralized iron.

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. The foot is also unusual, being armored at the sides with iron-mineralised sclerites. source

As a result their shell is super hard and can actually be picked with a magnet 🧲 🐌

But that's the only weird thing about these creatures. Surviving in such deep and extremes environments means that the volcano snail had to come up with some othe crazy adaptations to survive.

For example...They don't eat! That have an underdeveloped digestive system, that is proportionally about 10% of their more normal counterparts. For their actual nutritional needs they depend on endosymbiotic bacteria to cover their nutritional needs:

The snail's oesophageal gland houses symbiotic gammaproteobacteria from which the snail appears to obtain its nourishment. source

Another interesting fact is their heart. It's huge! About 4% of their total weight, one of the largest numbers in the animal kingdom. The reason for this is probably to provide enough oxygen both for the snail and the abnormally large number of the aforementioned symbiots.

Actually, many of the snail's adaptations appear as if they were made to first serve the bacteria and then the snail

It is hypothesized that the derived strategy of housing endosymbiotic microbes in an oesophageal gland, has been the catalyst for anatomical innovations that serve primarily to improve the fitness of the bacteria, over and above the needs of the snail. source

Unfortunately, Chrysomallon squamiferum was listed by the IUCN as endangered in 2019 due to risks from deep-sea mining in their habitat. Imagine losing such an amazing species that took one god knows how many million years to evolve just up satisfy human greed. Oh well.. Won't be the first.. Won't be the last 😅

Anyways, I hope you enjoyed reading about this unbelievable creature. This post has only touched the surface of all the anatomical peculiarities the species had to come up with, there's just a shit ton of cool stuff to say about it and I highly recommend you to visit the corresponding Wikipedia entry if you want to a more thorough read.

This is also a great video for those of you to lazy to read walls of text