Antenna (biology) - Crustaceans

Crustaceans

Crustaceans bear two pairs of antennae. The first pair are uniramous and are often referred to as antennules, while the second pair are biramous, meaning that each antenna is composed of two parts, joined at their base . In most adults, the antenna are sensory organs, but they are used by the nauplius larva for swimming. In some groups of crustaceans, such as the spiny lobsters and slipper lobsters, the second antennae are enlarged, while, in others, such as crabs, the antennae are reduced in size.

The large flattened plates in front of the eyes of a slipper lobster are the modified second antennae. The crab Cancer pagurus, showing its reduced antennae Antennules of the Caribbean hermit crab