Identification
Commonly known as the Bristly Chiton, this "armored wanderer" is a master of camouflage. Reaching up to 60mm in length, its body is dominated by eight overlapping valves (plates) that are often beautifully mottled in shades of olive-green, russet, and slate grey. The clinching field mark, however, is the fleshy girdle surrounding the plates. Look closely for 18 distinct tufts of translucent, needle-like bristles—four arranged around the head and seven pairs running down the sides. While it resembles *Acanthochitona crinita*, the Bristly Chiton is notably larger and more elongated, with a more "shaggy" appearance due to those prominent tufts.
Habitat & Range
This species is a staple of the Northeast Atlantic, ranging from the fjords of Norway down to the Mediterranean and North Africa. It thrives in the lower intertidal and sublittoral zones, down to depths of 50 meters. To find one, wait for a low spring tide and peer under stable, medium-sized boulders or deep within damp, shaded crevices where the humidity remains high.
Behaviour & Diet
By day, the Bristly Chiton is a sedentary hermit, suctioning itself so tightly to the rock that it becomes nearly impossible to remove without injury. It is a nocturnal grazer with a remarkable "homing" instinct; it leaves its specific resting spot (or "home scar") at dusk to forage, only to return to the exact same indentation before sunrise. It feeds using a radula—a tongue-like ribbon tipped with magnetite-capped teeth—to scrape films of algae, diatoms, and encrusting bryozoans off the rock surface.
Fascinating Fact
The Bristly Chiton literally sees through its own skeleton. Its valves are embedded with thousands of microscopic sensory organs called aesthetes. Some of these even contain tiny lenses made of aragonite (a mineral form of calcium carbonate), allowing the chiton to detect shadows of approaching predators through its armor!