Chiton glaucus
Chiton glaucus

Description: Chitons are in the class Polyplacophora (meaning “many plates.”) The class Polyplacophora is comprised of sluggish marine animals with flattened bodies. The order that Chiton glaucus is a part of is Chitonida. A distinctive feature of these primitive marine animals is a shell composed of eight separate but overlapping dorsal plates. Their heads are reduced and they have broad feet for locomotion. There are no eyes or tentacles. Chiton glaucus can grow up to 55m long.

Like most mollusks, they feed with a rasp like organ called the radula. Unlike most other mollusks their radulae are coated in an iron-containing mineral called magnetite. The most unique thing about chitons is their incorporation of this mineral into their teeth. From the name, you can tell that magnetite is a mineral that can become magnetized. That's not why chitons cover their teeth in it, though. In order to eat, chitons need incredible abrasive teeth that can scour away at rocks and expose algae, which means the teeth need to be coated in a tough material. Normal geologically produced magnetite is pretty tough, but, remarkably, the magnetite that chitons produce to coat their teeth is much tougher despite being made from the same molecules. The chiton's biochemical toolkit is able to produce magnetite in which the three dimensional structure is tweaked towards a tougher end result. It is absolutely astonishing!

Structure of a Chiton
Structure of a Chiton
Habitat: Cold water and tropical areas are areas that support all types of Chitons. They usually live on or underneath rocky surfaces, but do not be confused. Chiton glaucus is exclusively a marine animal. Low tide areas near the shore are common for shelled-mollusks, like Chitons.

Niche: Animals that feed on Chiton glaucus include humans, seagulls, seastars, crabs, lobsters and fish. The overwhelming amount of predators puts it close to the bottom rungs of the food chain. Their diet consists of algae and some bacteria, so they are herbivorous. Although some Chitons are predatory and feed on small invertebrates, like shrimp, Chiton glaucus is not.

Reproduction: Chitons partake in external fertilization. The male releases sperm, while the female releases eggs. More than likely, fertilization will occur in the surrounding water, or in the mantle cavity of the female. The eggs are equipped with a tough spiny coat and, like many other mollusks, a free-swimming larva is made. Uniquely, there is no intermediate stage between the larva and the adult for the Chiton glaucus. A segmented shell and foot form on opposite sides of the larva and the body elongates, instead.

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