Tube worms
The division of living beings into systematics is a continuous subject of research. Different systematic classifications exist side by side and one after the other. The taxon treated here has become obsolete due to new research or is not part of the group systematics presented in the German-language Wikipedia.
The tubular worms (Nemathelminthes or Aschelminthes), also known as round worms or hollow worms , are cylindrical, non-symmetrical worms with a length of a few millimeters to one meter. Tube worms form a group of primordial mouths (protostomia), which were previously regarded as taxons due to some similarities in their body structure . All tubular worms have a strongly developed foregut , which forms a muscular pharynx with cuticular stiffeners . Since the body cavity is not lined with an epithelium , it is usually interpreted as a primary body cavity (blastocoel). In addition, syncytia and multiple cell constancy (eutelia) often occur.
Systematics
The exact extent of the tube worms has always been controversial, the following taxa were usually assigned to them:
- Scratchworms (Acanthocephala)
- Belly parsley (Gastrotricha)
- Hookweed (Kinorhyncha)
- Corset animal (Loricifera)
- Roundworms (Nematoda), for example the intestinal parasites roundworm , whipworm , pinworm , hookworm and dwarf threadworm
- String worms (Nematomorpha)
- Priapulida (Priapulida)
- Rotifers (Rotatoria)
With the exception of the belly curls, the scratch worms and the rotifers, they form the subgroup Cycloneuralia of molting animals (Ecdysozoa) in the modern system .
proof
- Volker Storch, Ulrich Welsch: Short textbook of zoology . 7th edition. Gustav Fischer, Stuttgart, Jena, New York 1994, ISBN 3-437-20507-2 , pp. 426-433 .
Individual evidence
- ↑ Hans Adolf Kühn: intestinal parasites. In: Ludwig Heilmeyer (ed.): Textbook of internal medicine. Springer-Verlag, Berlin / Göttingen / Heidelberg 1955; 2nd edition ibid. 1961, pp. 834-841, here: pp. 837-840: Rundworms (Nemathelminthes).