Scalidophora
| Scalidophora | ||||||||||||
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Body sections and anatomy of a scalidophore. |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Scalidophora | ||||||||||||
| Luxembourg , 1995 |
The scalidophora ( Gr . Skaliden wearing) are a rank loose taxon , are united in the three strains of invertebrates, which priapulida (Priapulida) which loricifera (Loricifera) and the kinorhyncha (Kinorhyncha). All species in the group are bottom-dwelling marine animals.
features
The Scalidophora have a common feature of a body that can be divided into three sections, the front body, called introvert, the "neck" and the torso or rear body.
The introvert is formed by an evertable trunk, with the help of which the Scalidophora can move and which also carries the sensory organs. It is covered by special scales, the scalids. Each scalid contains sensory cells, is hollow inside and ends in a terminal pore. The mobility of the introvert is ensured by pulling back muscles, which are arranged in two rings and attach to long ectoderm cells . At the top of the introvert is the mouth, which is surrounded by sensory cells, and directly behind it is the brain. The introvert is radially symmetrical . The outer body cover (endocuticle) contains chitin .
Legend for the picture:
- Body sections (right):
- mc = mouth cone
- in = introvert
- nk = neck
- tk = trunk
- Organs (left):
- os = mouth stylets
- rb = annular ganglion
- sc = scalide
- ng = ganglion
- ir = intro representatives
- vn = ventral nerve cord
- gn = gonad
- gt = intestine
- pn = protonephridia
- cg = caudal ganglion
- ca = bristles
Most species of Scalidophora are very small, corset animals are only 100 to almost 500 micrometers in length, hookweeds are between 200 micrometers and one millimeter long and priapworms between 0.05 centimeters and 39 centimeters long.
The Scalidophora have been found in fossils since the Cambrian (e.g. Markuelia ) and are only the remainder of a group that was once much more species-rich.
literature
- Hynek Burda , Gero Hilken, Jan Zrzavý: Systematic Zoology. UTB, Stuttgart; : 1st edition 2008, pages 143-142, ISBN 3825231194
