Arhynchobdellida
| Proboscisless leeches | |
|---|---|
 |
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| A giant Americobdella species from southern Chile. | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Class: | Clitellata |
| Subclass: | Hirudinea |
| Infraclass: | Euhirudinea |
| Order: |
Arhynchobdellida Blanchard, 1894 |
| Suborders | |
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Erpobdelliformes |
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| Synonyms | |
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Arhynchobdellae Stuart, 1982 |
|
Erpobdelliformes
Hirudiniformes
and see text
Arhynchobdellae Stuart, 1982
Pharyngobdellae
Pharyngobdellida Johnson, 1913
The proboscisless leeches, Arhynchobdellida, are classified as an order of the Hirudinea. But leech taxonomy and systematics will eventually be revised in due time, not because there are many uncertainties about their phylogeny, but because the major clades of clitellate annelids - and whether the clitellates are themselves a clade - have not been fully elucidated. For example, the "true leeches" (Euhirudinea) might actually be synonymous with the Hirudinea, as all other leech-like annelids might not be very closely related to the true leeches.
Proboscisless leeches are generally freshwater or animals. They have usually 6-8, sometimes 5 pairs of eyes. Some - among them the well-known European Medical Leech (Hirudo medicinalis) of the Hirudiniformes - are bloodsuckers, while most - including the Kinabalu Giant Red Leech (Mimobdella buettikoferi) of the Erpobdelliformes - are predators that hunt small invertebrates which are swallowed whole.
Given the systematic uncertainties, the proboscisless leeches have been treated at varying ranks, and the alternate name Arhynchobdellae is also sometimes found.
Arhynchobdellida systematics has been revised in modern times. Formerly it was believed that they can be divided into a jawed and a jawless order. However, the lack of jaws does not denote a particularly close relationship. Jawed leeches are more numerous but exclusively found among the Hirudiniformes, while the jawless "Pharyngobdellida" (or "Pharyngobdellae"), also known as "worm-leeches", are more diverse and occur in the Hirudiniformes and the Erpobdelliformes alike.
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