Querder

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The eyeless, worm-like larvae of the lampreys (Petromyzontidae) are called Querder (from Old High German querdar , 'bait', 'bait'), also called Ammocoetes . The lampreys belong to a group of primeval vertebrates without a jaw apparatus, the round-mouthed (formerly: " Agnathen "). During the larval time in fresh water, which lasts up to five (exceptionally probably seven) years and ends with the conversion to adult lamprey, which takes around three to four months , the animals live hidden in the soft bottom of slowly flowing water. There they make an arch-shaped mud pipe, which they solidify with the help of a glandular substance. Only the bilobed mouth protrudes slightly into the flowing water in order to filter food particles such as plankton and suspended particles from the water with bristle-like appendages, the cirrus . In the event of a fault, they withdraw far into the tube. The breathing is largely through the skin, until the adult lamprey is a simple, well from intestinal separate gill bag trained.

In the past, lamprey larvae were considered to be a separate species and given the scientific name Ammocoetes branchialis (in German also "Steinquerder").

  • Querder or Ammocoetes

  • Older lateral derailleur of the brook lamprey from the Spree

  • Side view of the head of a cross of the S of the sea lamprey .

  • Mouth of a sea lamprey cross-earth.

  • Body end of a sea lamprey transverse rod.

literature

Individual evidence

  1. ↑ Brockhaus Encyclopedia , 1989, Volume XIII, p. 31.