Uropod

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Underside of a lobster , the finger in the lower left corner of the picture is touching the exopodite of a uropod.

As uropods the last is Pleopodenpaar the Higher crabs (Malostraca, Eumalostraca) because it differs in construction from the others.

They are the limbs of the sixth abdominal segment and are usually two-part, that is, as a split bone, divided into exo- and endopodites. The somewhat larger exopodite can be divided by a diaeresis , a transverse seam or furrow. Uropods have a plate-like, flat shape in most groups. If they are fanned out, they represent the tail fan with the telson . In case of danger, this can be moved forward by ventral , powerful blows of the pleon , so that the cancer is suddenly pushed backwards and can flee quickly. Some groups of higher crustaceans, such as most of the Peracarida , the Bathynellacea, and the Cumacea , have rather rod-shaped uropods instead.

In hermit crabs , uropods serve as holding organs, in almost all crabs and some Lithodidae the uropods have regressed.

literature

  • W. Westheide, R. Rieger: Special Zoology. Part 1. Protozoa and invertebrates . Gustav Fischer Verlag, Stuttgart / Jena / New York 1996, ISBN 3-437-20515-3 .
  • 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. 931 f .

Web links

  • Joel Martin: Diaeresis. In: Crustacea Glossary. Natural History Museum Los Angeles County, accessed July 4, 2012 .
  • Joel Martin: Uropod. In: Crustacea Glossary. Natural History Museum Los Angeles County, accessed July 4, 2012 .