Glass crabs
| Glass crabs | ||||||||||||
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larva |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Leptodora kindtii | ||||||||||||
| ( Focke , 1844) |
The glass crayfish ( Leptodora kindtii ) is the only representative of the order or suborder Haplopoda. This belongs to the claw tails (Onychura) within the leaf crabs (Branchiopoda).
The glass crayfish lives predatory in lakes and large rivers of various small crustaceans ( anomopods , copepods ) and rotifers .
Construction of the glass crab
The glass crab reaches a maximum body length of 14 millimeters. It has reduced the shell, which is typical for the other representatives of the clawed tail, to a dorsal brood sac in the females and has adapted to a predatory way of life. The body is very transparent, elongated and has a short trunk, the segment boundaries of which are completely dissolved. The abdomen is long and consists of three segments and the telson with an abdominal fork ( furca ).
The first antennae is short and single-branched in females, the second antennae are large two-branched swimming legs with long swimming bristles. The mandibles are rod-shaped biting tools, the two pairs of maxillae are missing. The ventral side of the torso is bent perpendicular to the body axis so that the thorax legs protrude forward. In this way, these form a collecting basket, with the first pair of legs being significantly longer than the others. At the front end of the head lies a single, large compound eye .
Reproduction and development
The glass crabs only have one sexual reproduction phase in autumn (monocyclic reproduction). The males, which are a little smaller than the females, take hold of them with the help of their first antenna, which has been developed into grasping organs, as well as the first trunk bone and fertilize it. The eggs are released freely into the water and after winter they hatch Meta nauplius larvae with very large antennae. They develop into adult animals over several moults.
Parthenogenetic reproduction occurs in summer , with the young developing in the female's brood sac.
Systematics of the Haplopoda
The Haplopoda used to be grouped together with the Onychopoda and the Anomopoda as water fleas (Cladocera), but this group probably does not represent a natural unit. The actual assignment in the system of the clawed tails is controversial.
literature
- Ax P (1999): "The system of the Metazoa II. A textbook of phylogenetic systematics"; Gustav Fischer Verlag.
- Gruner HE (1993): "Class Crustacea"; in Gruner HE (Ed.): "Textbook of Special Zoology, Volume I, Part 4: Arthropoda (without Insecta)"; Gustav Fischer Verlag
- Schminke HK (1997): "Crustacea, Krebse"; in Westheide, Rieger (Ed.): "Special Zoology Part 1: Protozoa and Invertebrates"; Gustav Fischer Verlag
- Vijverberg J. (2005): "Effects of Predation and Food on the Population Dynamics of the Raptorial Cladoceran Leptodora kindtii"; Limnology and Oceanography, 50 (2), 455-464