Cephalothorax

Cephalothorax

The cephalothorax is a major body part found in certain arthropods, particularly within the subphylum Chelicerata and the class Malacostraca of the subphylum Crustacea. It is a fused body region that combines the head and the thorax, distinct from the abdomen.

Diagram of a general malacostracan showing the cephalothorax.

Structure

In arthropods with a cephalothorax, this body region typically houses the sensory organs, mouthparts, and appendages used for locomotion and feeding. The cephalothorax is covered by a hard protective shell called the carapace, which provides support and protection to the internal organs.

Function

The cephalothorax serves several critical functions:

• Protection: The carapace shields the internal organs from physical damage and predation.
• Support: It provides a rigid structure for muscle attachment, facilitating movement.
• Sensory Integration: Houses sensory organs such as eyes and antennae, allowing the organism to interact with its environment.

Examples

The cephalothorax is a characteristic feature of several arthropod groups:

• Arachnids: In spiders and scorpions, the cephalothorax bears the legs and pedipalps.
• Crustaceans: In crabs, lobsters, and shrimp, the cephalothorax includes the head and thoracic segments, often covered by a large carapace.

Related pages

• Arthropod anatomy
• Carapace
• Chelicerata
• Crustacea