Pleopod

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Pleopods of a shrimp
Eggs attached to the pleopods in American lobsters

As pleopods , Abdominalbeinpaare or webbed feet , also swimming legs (ger .: swimmerets) called, refers to the first five pairs of limbs of the abdominal segments at higher crustaceans .

As a rule, pleopods are split legs and thus divided into exopodite and endopodite (outer branch and inner branch), which are usually built similarly. They are stylus-shaped, flattened or leaf-shaped and can have bristles. Originally the pleopods are swimming organs and are therefore well developed in swimming crustaceans such as shrimp . In benthic crabs or land crabs that move continuously using striding legs , pleopods may be regressed or completely absent. For example, males of crabs almost always lack the pleopods of the 3rd to 5th pleon segment and the females the first pair.

Sometimes the endopodites have a small hook-shaped appendix, the appendix interna , with which the pleopods of a pair can hook to form a common unit. The second pleopods of the males can have a finger-shaped extension on the endopodite, the appendix masculina .

In males, the first two pleopods can be transformed into gonopods as auxiliary organs for copulation . Females of the decapods , with the exception of all Dendrobranchiata except for the Luciferidae , attach fertilized eggs to the pleopods, where they remain until the larvae hatch. In Thymops birsteini , the larvae also remain briefly on the pleopods of the mother.

The limbs of the sixth abdominal segment (in the case of the amphipods, those of the last three segments) are called uropods .

See also

literature

  • Alfred Kaestner: Textbook of special zoology . Ed .: Hans-Eckhard Gruner. 4th edition. tape 1 : invertebrates. 4th part: Arthropoda (without Insecta) . Gustav Fischer Verlag, Jena Stuttgart New York 1993, ISBN 3-334-60404-7 , p. 473, 714, 858, 931 .
  • Uwe Werner: Pleopods. In: Claus Schaefer, Torsten Schröer (Hrsg.): The large lexicon of aquaristics. Eugen Ulmer, Stuttgart 2004, ISBN 3-8001-7497-9 , p. 784.

Web links

  • Joel Martin: Pleopod. In: Crustacea Glossary. Natural History Museum Los Angeles County, accessed July 4, 2012 .
  • Joel Martin: Appendix interna. In: Crustacea Glossary. Natural History Museum Los Angeles County, accessed July 4, 2012 .
  • Joel Martin: Appendix masculina. In: Crustacea Glossary. Natural History Museum Los Angeles County, accessed July 4, 2012 .