I learned about a new animal that I had never heard of before this last visit to Costa Rica. It’s called a Chiton, and it is in a class of its own, the Polyplacophora, in the Mollusc phylum. To give you an idea of the taxonomy, all insects are in the same class, Insecta, so this is a very taxonomically distinct group. It’s also globally distributed, so if I had looked closer, I probably would have found these guys at other intertidal zones I’ve visited.
The reason I never saw them is that they are very cryptic little animals. Many species live in dark crevices between rocks in the intertidal zone, and they don’t like being exposed to too much light. Wikipedia mentions a species that lives 6,000 m deep in the ocean! (okay, so I haven’t had a chance to run into that one!)
Chitons are like tanks, they have a dorsal shell of interlocking, rock hard plates. They are unique among animals in that they have teeth made of iron crystals (magnetite) along their scraping tongue, so they are really good scrapers of algae!
The largest chiton is 33 cm in length (that’s more than a ft long)!
Just goes to show…the closer you look, the more you see!
Have you seen a chiton where you are? If there’s an ocean nearby, maybe you should see if you can find one in the intertidal zone!