Order Decapoda
Crabs, Lobsters, Shrimp, and Crayfish
| Size: Very small to large; from a few millimeters to half a meter | Antennae: Two pairs |
| Diet: Other living organisms, decaying matter, and wastes of living things | Mouthparts: Mandibles |
| Habitat: Most aquatic areas | Legs: Four pairs |
| Morphology: Young are similar in appearance to adults | Front Wings: Not present |
| Segmentation: Two body regions, a cephalothorax and an abdomen | Hind Wings: Not present |
| Distinctive Characteristics and Behaviors: Decapods possess chelipeds, a pair of legs that have become modified into pinching claws. They lack normal orientation capabilities, and each time they molt, they must pick up grains of sand. The sand shifts with gravity, telling them which way is up and which is down.
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Champaign, IL, 9-18-02, R. Sandretto
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