Rock-a-bye Chiton, on the sea floor… What ARE these things? Aaron and I encountered these strange creatures on Maddie’s memorial walk through the tidal pools in La Jolla. The colorful crabs, sea anemones, snails and mollusks (sort of) outstripped my interest in these creatures. In going through possible photos to share, I came back to this one and the question I had immediately upon seeing them for the first time: What ARE these things?
That day the word “trilobite” came to mind. I have no clue how I even know that word. Perhaps something stored away during my middle grade obsession with archeology. Maybe through popular culture (sigh, from where too damned much of my knowledge comes).
Turns out my classification was wrong. ‘Dead’ wrong, in fact. You see, trilobites are—well, kind of, sort of extinct. Sure, they had a good run. They feasted in the swarmy milieu of ocean brine for roughly 270 million years, from the Early Cambrian through the end of the Permian era (the writing was on the wall as early as the Devonian era, though).
My little modern day guys are Chitons, which aren’t even arthropods (whereas trilobites are). You know, arthropods-invertebrate, exoskeletal animals with jointed appendages and the ultimate creep factor. Herein lays the key to my confusion. Some people refer to Chitons as trilobite imposters because they too have a hard external component (shell in this case) composed multiple plates (resembling the exoskeleton). Flip these guys over to tickle their bellies and you find not feet but a “snail-like” foot. A little brainless, Chitons perceive the word through photosensitivity (not “true” sight) and through tactile sensation.
Alas, Chitons beat out trilobites in terms of longevity. 400 million years of fossil records instead of 270 million. And while I don’t like to make fun of names, Chiton does strike me as strange. It refers to a Greek word for clothing. Perhaps it has something to do with the way the shell is draped around the soft flesh.
What prehistoric creatures have you encountered?