#exoskeleton

• Acanthophorous — A scholarly morphological term used as an adjective to describe an organism, organ, or anatomical structure equipped with spine-bearing elements, thorns, or sharp rigid protrusions. As a masculine noun, it defines a skeletal part, an appendage, or a specialized cuticular zone that supports or bears a defensive spine (frequently encountered in the exoskeleton structure of some marine crustaceans, bryozoans, or fossil fishes from the Paleozoic era).
• Protective shell — A rigid anatomical structure resembling a shield, shell, test, or protective skeletal frame, composed of calcareous, chitinous, or siliceous matter, which partially or fully encloses the body of certain invertebrates (such as some crustaceans, mollusks, or protozoans). It serves an essential function as a predator barrier, structural support for soft tissues, and defense against dehydration.
• Apodemes — Internal ingrowths or ridges of the arthropod exoskeleton that serve as structural supports and provide solid points of attachment and leverage for locomotory muscles; internal cuticular projections. These chitinous formations fulfill the function of a functional endoschelet, being essential for the biomechanics of insect and crustacean movement.
• Arthropod — An invertebrate animal characterized by the presence of an articulated chitinous exoskeleton and legs or appendages made of movable segments. As an adjective, the term describes an organism or anatomical structure specific to this group of creatures, which includes insects, arachnids, crustaceans, and myriapods, representing the most numerous and diverse phylum in the animal kingdom.