Rhynchobdellida
Order of annelids
From Wikipedia, the free encyclopedia
Rhynchobdellida (from the Greek rhynchos, mouth, and bdellein, sucking),[1] the jawless leeches[2] or freshwater leeches,[3] are an order of aquatic leeches.[4][5] Despite the common name "freshwater leeches", species are found in both sea and fresh water. They are defined by the presence of a protrusible proboscis instead of jaws, and having colourless blood.[6][7][8] They move by "inchworming"[9] and are found worldwide. The order contains 110 species, divided into 41 genera and three families.[9] Members of the order range widely in length, usually between 7 and 40 mm.[3] They are hermaphrodite.[3] The order is not monophyletic.[10]
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| Jawless leeches | |
|---|---|
| |
| Branchellion parkeri | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Clade: | Pleistoannelida |
| Clade: | Sedentaria |
| Class: | Clitellata |
| Subclass: | Hirudinea |
| Infraclass: | Euhirudinea |
| Order: | Rhynchobdellida Blanchard, 1893 |
| Families | |
| |
Appearance and eating habits
Instead of jaws and teeth, Rhynchobdellidae have protrusible proboscises, which they use to penetrate the host's skin.[3][11] Mouths of Rhynchobdellidae species are small holes from which the proboscis can be protruded.[11] The proboscis then sucks out the desired bodily fluid from the host: usually blood or coelomic fluid in the case of invertebrate victims.[10]
Rhynchobdellidae are either sanguivorous or predatory.[citation needed] Sanguivorous species usually feed on a variety of other animals, using their proboscis to host's skin. They generate anticoagulants (like mosquitoes) and natural anaesthesia to help the feeding.[3] Predatory Rhynchobdellidae have digestive enzymes that help break down their prey, which usually consists of small invertebrates such as insect larvae or amphipods.[3]
Families
Glossiphoniidae (Freshwater jawless leeches)
The Glossiphoniidae, the freshwater jawless leeches,[citation needed] or leaf leeches (due to their shape)[12] are freshwater leeches, flattened, and with a poorly defined anterior sucker.[3] The family Glossiphoniidae contains one of the world's largest species of leech, the giant Amazon leech, which can grow up to 45 cm in length.[13] Many species show extended parental care, keeping eggs in nests or pouches and caring for and feeding the young.[3][14] They feed on both vertebrate and invertebrate animals.[5]
Piscicolidae (Fish leeches)
The Piscicolidae occur in both freshwater and seawater, have cylindrical bodies, and a usually well-marked, bell-shaped, anterior sucker.[3][5] They are parasites of fish.[12][5] The family was originally divided into three subfamilies based on species' pulsatile vesicles, but the subfamilies were disbanded in 2006.[5]
Ozobranchidae (Turtle leeches)
Ozobranchidae are primarily parasitic on marine turtles, and are sometimes merged with the Piscicolidae.[3][5]
