Lynceidae
| Lynceidae | ||||||||||||
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Lynceus brachyurus mating |
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| Systematics | ||||||||||||
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| Scientific name of the subordination | ||||||||||||
| Laevicaudata | ||||||||||||
| Linder, 1945 | ||||||||||||
| Scientific name of the family | ||||||||||||
| Lynceidae | ||||||||||||
| Baird , 1845 |
The Lynceidae represent the only family in the suborder Laevicaudata that belongs to the gill pods (Branchiopoda). About 40 species of Laevicaudata are known worldwide, all of which are part of the Lynceidae family.
Like the Spinicaudata , the Laevicaudata live mainly on the ground and in the mud of small bodies of water that regularly dry out.
Construction of the Laevicaudata
Lynceidae usually reach body lengths of about 6 millimeters, with the males being significantly smaller than the females. Like almost all members of the clawed tail, the body of the animals is surrounded by a two-lobed shell ( carapace ), the head has a large head shield, which is articulated to the carapace. The shell has no or only indistinct growth rings and is held together with a sphincter muscle.
The trunk (thorax) of the Lynceidae consists of 12 segments in the female and 10 in the male. Each segment has 1 pair of leaf legs, the original structure of which is difficult to recognize. The oar stroke of the legs creates a stream of water that transports oxygen and nutrient-rich water into the centrally located food channel and to the gills. Food particles are filtered out by bristles and transported forward to the mouth opening. The last segment ( telson ) has no strong claws and is only occupied by small spines.
The second antenna of the animals is very strong and has two branches and serves as a swimming leg, for this reason it has numerous long swimming bristles. All Lynceidae have a pair of compound eyes and a nauplius eye with 4 cup oocelles.
Reproduction and development
The reproduction is bisexual in all Lynceidae. In the males, the first two leaf bones have been transformed into grasping organs with which they can hold the females for copulation.
The female attaches the eggs in large egg balls to the 9th and 10th pairs of legs and releases them during the next molt. The eggs are drought-resistant and can survive for some time in dry soil. No nauplius larvae hatch from the eggs , but more developed larvae with a head shield and lateral lobes at the front end.
Systematics of the Laevicaudata
The Lynceidae used to be grouped together with the Spinicaudata to form the mussel shells (Conchostraca), but it is highly likely that this group does not represent a natural unit.
literature
- P. Ax: The system of Metazoa II. A textbook of phylogenetic systematics. Fischer, 1999, ISBN 3-437-35528-7 .
- HE Gruner: Class Crustacea. In: HE Gruner (Ed.): Textbook of Special Zoology. Volume I, Part 4: Arthropoda (without Insecta). Fischer, 1993, ISBN 3-334-60404-7 .
- J. Olesen: A phylogenetic analysis of the Conchostraca and Cladocera (Crustacea, Branchiopoda, Diplostraca). In: Zool. J. Linn. Soc. Volume 122, Issue 4, London, April 1998, pp. 491-536.
- EW Roessler: Review of Colombian Conchostraca (Crustacea) - ecological aspects and life cycles - family Cyclestheriidae. In: Hydrobiologia. 298, 1995, pp. 113-124.
- HK make-up: Crustacea, crayfish. In: W. Westheide, R. Rieger (Ed.): Special Zoology. Part 1: Protozoa and invertebrates. Fischer, 1996, ISBN 3-437-20515-3 .