Crustaceans Subphylum Crustacea

Typically have: 2 Pairs of antennae 2 body sections (sometimes 3) Chewing mouth parts called mandibles

Abdomen Cephalothorax Carapace Antenna (2 nd ) Cheliped with claws Walking legs Swimmerets 1 st pair of antennae Tail (1 st pair of legs) (Fusion of head + thorax)

Carapace covers the cephalothorax. Protects the gills

Appendages: Have different functions: Walking, Sensing the environment, Feeding, Defending against predators, Attracting mates 1 st pair: Chelipeds – used for collecting and manupilating food (catch, pick up, crush, cut) Decapods – 5 pairs of legs (Deca = 10)

Fiddler crabs – Male crabs use its large claw to attract females Some hermit crabs use the claws to block the entrance of the shell

4 Pairs of walking legs Swimmerets - Used for swimming and reproduction (males for transfer of sperm, females to hold Eggs and young)

Male

Groups of Crustaceans: 1. Decapods: Primarily live in saltwater environments. 5 Pairs of appendages Fused body segments – Cephalothorax and abdomen

Antennae – Have sensory hairs – used for sensing the environment. (Crayfish mainly) Other crustaceans – Swimming and Filter feeding Mandible – mouthpart used for biting and chewing Tail – paddle-like appendages fused with last segment

2. Barnacles: Sessile Carapace similar to mollusk mantle, secretes a calcium shell Feed by sweeping food into its mouth with feet

3. Isopods Seven pairs of legs Most are marine and freshwater scavengers Pill bugs and Wood lice (terrestrial)

4. Tongue worms: Parasitic No eyes, mandibles or antennae. Have lost most of their limbs