Schlundegel
| Schlundegel | ||||||||||||
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| Scientific name | ||||||||||||
| Erpobdelliformes | ||||||||||||
| Sawyer , 1986 |
The throat leeches (Erpobdelliformes, formerly Pharyngobdelliformes Caballero , 1952 , Pharyngobdellida or Pharyngobdellae Johansson , 1913 ) are a subordination of the leeches (Hirudinea), which as predators feed on various small animals - mostly insect larvae or annelids.
features
The throat leeches are characterized by a long, strong, very muscular throat, with the help of which prey animals are devoured as a whole. Proboscis and jaws are missing. Likewise, the intestine has no blind sacs, which is why the pharynx are dependent on more frequent meals than the jaw rule . The Schlundegel have 3 to 4 pairs of eyes.
The coelom of Schlundegel is formed as in the jaw leeches as a system close vessels through which the hemoglobin-containing , as blood flows serving coelomic fluid and therefore constitute a secondary vascular system, while the primary vascular system is fully reduced. The two laterally running muscular main vessels pulsate and thus have a cardiac function . The space between the vessels is criss-crossed with muscle cords and filled with connective tissue.
The hermaphrodite animals lack a penis; the sperm is exchanged in spermatophores and attached to the sex partner's body, and the sperm penetrate the skin.
Occurrence, habitat and species examples
The throat leeches are common in standing and flowing inland waters around the world, but there are also some species known as earth leeches that live on land in moist soils. There are no gullet leeches in sea water.
The eight-eyed pharynx or dog leech ( Erpobdella octoculata ), which belongs to the family of roller gels and which feeds on mosquito larvae and mud- tube worms , is very common in rivers of Central Europe that are heavily polluted by saprobial activity . The Freiburg Bächle leech ( Trocheta intermedia ), found exclusively in the rivers of the city of Freiburg im Breisgau , shows a similar way of life .
Systematics
Peter Ax calls the autapomorphism of the monophyletic group Pharyngobdelliformes or Erpobdelliformes the large, spiraling pharynx , with the help of which large prey can be devoured. On the basis of recent molecular genetic studies, a number of jawless leeches have been added to the Hirudiniformes , most of which include the jaw rule. The Erpobdelliformes are hereby limited to the following families :
- Erpobdellidae Blanchard, 1894
- Gastrostomobdellidae Richardson, 1971
- Orobdellidae Nakano, Ramlah & Hikida, 2012
- Salifidae Johansson, 1910
literature
- Peter Ax: The system of Metazoa II. A textbook on phylogenetic systematics. Gustav Fischer Verlag, Stuttgart / Jena 1999. Chapter Hirudinea , pp. 65–73.
- Urania Tierreich , Volume 2. Urania-Verlag, Leipzig / Jena / Berlin 1966. p. 89, order Pharyngobdelliformes, Schlundegel .
- Roy T. Sawyer: Leech Biology and Behavior. Clarendon Press, Oxford 1986. Suborder: Erpobdelliformes. New name. = Pharyngobdelliformes Caballero, 1952. p. 693.
- C. Wesenberg-Lund, O. Storch: Biology of freshwater animals - invertebrates. Published by Julius Springer, Vienna 1939. p. 366.
- Hugh F. Clifford: Aquatic Invertebrates of Alberta: An Illustrated Guide. University of Alberta Press, Edmonton (Alberta) 1991. pp. 70-85.
- Takafumi Nakano (2011): Holotype redescription of Mimobdella japonica (Hirudinida, Arhynchobdellida, Erpobdelliformes) and taxonomic status of the genus Mimobdella. ZooKeys 119, pp. 1-10. Doi 10.3897 / zookeys.119.1501
- Takafumi Nakano, Zainudin Ramlah, Tsutomu Hikida (2012): Phylogenetic position of gastrostomobdellid leeches (Hirudinida, Arhynchobdellida, Erpobdelliformes) and a new family for the genus Orobdella. Zoologica Scripta 41 (2), pp. 177-185. Doi 10.1111 / j.1463-6409.2011.00506.x