Class Branchiopoda (Branchiopods)

Major Atributes:

  1. Small, mostly freshwater crustaceans; usually live in absence of fish.
  2. Use leaf-like trunk appendages for swimming and filter-feeding.
  3. Flattened leg-like structures extend from first segment and act as gills ("Gill legs"--branchio-poda).
  4. Carapace present in all groups but one.
  5. Reproduce both sexually and asexually; keep eggs in brood chamber.
  6. Ability to resist dessication in eggs.
  7. Egg-laying is closely related to moulting.


Description:

The branchiopods consist of two major groups, the Anostracans and Cladocerans which are called fairy shrimp and water fleas respectively. Fairy shrimp live in freshwater pools and springs, and unlike other branchiopods, they lack a carapace and have stalked eyes. Their bodies are elongated, often with more than 20 trunk segments. Most are about 1cm in legth, however some giants have been known to reach 10cm. Fairy shrimp swim upside down, beating their trunk appendages in rhythm. Setea located on their legs capture food particles throughout the beating movement and the particles are then passed along a groove on the ventral side to the mouth. Mating occurs by the male fairy shrimp clasping the female with its second antennae. The female lays and stores its eggs in a brood sac before releasing them. Fairy shrimp hatch as nauplii and are usually mature adults in one week. Water fleas are laterally flattened with a carapace which covers the body trunk but not the head. Most of these branchiopods are between 1-5mm in length. A powerful set of second antennae serve in swimming and usually two of the five segments of the trunk serve as filtering appendages. Most water fleas live in freshwater environments, filtering small particles, however a few are marine carnivores. These organisms reproduce mostly by parthenogenesis and brood their eggs in a dorsal chamber.

Some Interesting Facts:


Some Pertinent Books Found in Lamson Library:

  1. Banister, Dr. Keith and Dr. Andrew Campbell. 1985. The Encyclopedia of Aquatic Life. New York: Facts on File.
  2. Bertin, Leon. 1976. Larousse Encyclopedia of Animal Life. New York: The Hamlyn Publishing Group Limited.

(Danielle M. Mayhew, Fall 1994; edited by T. Shultz, Spring 1995)