Spadefoot molluscs: huge 18 cm “teeth” on the ocean floor (8 photos)
Giant fangs are scattered along the bottom of all oceans, all seas, bays and lagoons. The largest ones reach 18 centimeters - three times longer than the teeth of a great white shark! The beast from which such teeth grow must be at least the size of a megalodon! But why are scientists silent? Are there really huge superpredators living somewhere in the depths, whose existence is carefully hidden? 
The tooth fairy on the seabed hit the jackpot.
Those with strange fangs live at the bottom, in the dark depths of deep water. These are ancient carnivorous creatures that date back to the beginning of time - their remains are 485 million years old! During this time, they filled the entire ocean... But there is nothing to hide here, because all these “teeth” found are not teeth at all. And the shells! Meet spadefoot molluscs, or scaphopods, very ancient and very simple animals. 
Hello, nice to meet you! Hey, where are you running to?
From a taxonomy point of view, spadefoots are something between an octopus and a snail. But outwardly they are not similar to either one or the other. But they are very similar to each other! Spadefoots have 26 genera and almost 1000 species. Do you know what makes this whole bunch different? The ribbing of the shell, the color and minor modifications of a couple of organs - the legs and pharynx. What a variety! This feature explains why the same “teeth” are found in all seas and oceans - it’s just that all spadefoots are almost identical! 
Free sharpening in the middle of the ocean. Go - collect!
If you look into the inner world of a mollusk, you can see something interesting. Their body gets by with almost no organs! Heart, kidneys, lungs, gills, brains - all this is bullshit for nerds. But the digestive and reproductive apparatus of the mollusk are developed to 5+. 
This creature is so secretive that there are not even normal pictures of it!
The digestive apparatus is located at the head end of the spadefoot, where the shell is wider. Thin tentacles-captaculas with Velcro at the ends search for the smallest edible particles and microorganisms in the substrate. The shovelfish will crush them with a radula - a thing that replaces teeth for mollusks. She grinds what she has honestly obtained, as if on a grater, sending her on a further journey through the gastrointestinal tract. 
Someone: don't bury yourself in work! So it’s not far from burnout! I'm at work:
The reproductive apparatus is located approximately in the middle of the shell and is one large gland. Despite the simplicity of the structure of spadefoots, they are dioecious. That is, every clam is either a boy or a girl—no middle ground. After maturation, the sex cells are ejected from the rear end of the animal and, by some miracle, find cells of the opposite sex. How exactly does this happen? Scientists have not yet figured out whether sea “teeth” lead too secretive a lifestyle. 
No, this is not a sudden transformation of a mollusk into a crab. It’s just that arthropods brazenly occupied the empty shells of the spadefoot.
For modern humans, spadefoot mollusks are of little value. Unless paleontologists can determine the approximate age of the found remains from their accumulations. But animals used to be highly valued for their shells! 
What if this is really someone’s fang, and not a mollusk shell?!
For some tribes and nationalities, spadefoot shells served as money. Unlike the shells of other mollusks, the “teeth” are not so easy to obtain. They rarely wash ashore, because the animals do not live in the intertidal zone. Mollusks burrow into the ground at a depth of up to 6 kilometers! 
They don’t want to meet a person so much that they sit at great depths, and even in the ground.
This is why spadefoot shells were so prized. The longer and more beautiful, the more expensive they were. The rich could even afford jewelry made from mollusk shells - beads, necklaces and stripes symbolized the status of their owner. The most chic thing is a nose ring made of shell!
