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