Anamerism
Anamerism occurs in some groups of arthropods, and especially in cancers . This means that at the time of hatching, the complete number of body segments typical for the adult is not yet available. The missing segments are created postembryonally in the larva, which can be done in two different ways:
With regular anamerism , the new segments are formed in stages, that is, with each moult, a new segment is activated from the head downwards. Regular anamerism is particularly typical of the crayfish nauplius larvae .
In the case of irregular anameria , the rear body segments function earlier than those closer to the head, which can be an adaptation to special living conditions.
See also
literature
- Rüdiger Wehner, Walter Gehring: Zoology . 23rd, revised edition. Georg Thieme, Stuttgart 1995, ISBN 3-13-367423-4 , p. 682.
Web links
- Anamerie in the lexicon of biology science online; Retrieved February 10, 2012