Chitons are fascinating marine mollusks that often go unnoticed due to their appearance, resembling specks of seaweed on intertidal rocks. However, these creatures possess remarkable features, such as eyes embedded in their plate mail shell and teeth coated in the iron mineral magnetite, making them the hardest material created by a living organism. Some species even use the iron mineral santabarbaraite.
Despite their relation to squid, snails, and scallops, chitons’ eyes are not located on their soft bodies but are instead embedded directly into their segmented shell. These sensory organs, known as aesthetes, are still being studied to understand their function, but they may have rudimentary light-detecting capabilities.
These aesthetes likely served as the basis for the evolution of two types of eyes in some chitons: shell eyes and eyespots. The shell eyes are relatively large and have a lens made of the mineral aragonite, similar to human eyes, while the eyespots are more numerous and less complex.
2024-03-05 02:00:04
Original from phys.org