Amphipoda
Amphipoda is an order of crustaceans that includes about 10,000 species. They are commonly called amphipods, and can be found in marine, freshwater, and terrestrial environments. Amphipods are typically small, ranging in size from a few millimeters to several centimeters. They are characterized by a laterally compressed body, with a pair of antennae, seven pairs of legs, and a pair of uropods. The first pair of legs are often enlarged and used for grasping prey. Amphipods are important members of the food web, serving as prey for fish, birds, and other marine animals. Some species are also known to be scavengers, feeding on dead organisms.
Characteristics
Amphipods have a number of distinguishing characteristics that set them apart from other crustaceans. These include:
- Laterally compressed bodies: Their bodies are flattened from side to side, which allows them to move easily between rocks and other objects.
- Lack of a carapace: Unlike many other crustaceans, amphipods do not have a hard outer shell covering their head and thorax.
- Seven pairs of legs: Amphipods have seven pairs of walking legs, the first pair of which is often enlarged and used for grasping prey.
- Antennae: They have a pair of antennae that are used to sense their surroundings.
- Uropods: Amphipods have a pair of uropods, or tail appendages, that are used for swimming and maneuvering.
Environments
Amphipods are found in a wide variety of environments, including:
- Marine: Most amphipod species are found in the ocean, where they inhabit a variety of habitats, from the intertidal zone to the deep sea.
- Freshwater: A number of amphipod species are found in freshwater lakes, rivers, and streams.
- Terrestrial: Some amphipod species are adapted to living on land, particularly in damp environments such as leaf litter or under rocks.
References
- Wikipedia: Amphipoda
- WoRMS: Amphipoda
- NCBI: Amphipoda