| True leeches | |
|---|---|
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| A true leech in a Sydney suburb | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Class: | Clitellata |
| Subclass: | Hirudinea |
| Infraclass: | Euhirudinea |
| Orders | |
Euhirudinea, the true leeches, are an infraclass of the Hirudinea. [1]
These clitellate annelids are of somewhat unclear relationships; namely the relationships of Hirudinea with oligochaetes are in need of revision. It may be that the presumed sister taxon of the Euhirudinea, the Acanthobdellidea, turns out to be more distantly related, as was already the case with the Branchiobdellida. Thus, eventually Euhirudinea might become a junior synonym of Hirudinea.
True leeches are subdivided into two groups, the Arhynchobdellida or Arhynchobdellae (proboscisless leeches), and the Rhynchobdellida or Rhynchobdellae (jawless leeches). Note that the lack of jaws is a plesiomorphy, while the presence of a proboscis is an apomorphy – not all Arhynchobdellida have jaws, but all Rhynchobdellida have a proboscis. The best-known leech species, Hirudo medicinalis (European Medical Leech), belongs to the Arhynchobdellida.
Euhirudinea leeches tend to hunt for nutrients in the morning or afternoon. Leeches that hunt in the morning are found in larger sizes than those who hunt in the afternoon. Therefore, feeding in the morning seems to be more nutritious for the leeches than in the afternoon. Terrestrial Euhirudinea leeches, which inhabit tropical or subtropical environments have been found a greater number on-trails compared to off-trail numbers. [2]
Rhynchobdellida, the jawless leeches or freshwater leeches, are an order of aquatic leeches. 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. They move by "inchworming" and are found worldwide. The order contains 110 species, divided into 41 genera and three families. Members of the order range widely in length, usually between 7 and 40 mm. They are hermaphrodite. The order is not monophyletic.
The Clitellata are a class of annelid worms, characterized by having a clitellum - the 'collar' that forms a reproductive cocoon during part of their life cycles. The clitellates comprise around 8,000 species. Unlike the class of Polychaeta, they do not have parapodia and their heads are less developed.
Haemadipsidae are a family of jawed leeches. They are a monophyletic group of hirudiniform proboscisless leeches. These leeches have five pairs of eyes, with the last two separated by two eyeless segments. The family is monotypic, containing only the subfamily Haemadipsinae, though as the family can apparently be divided into two or three distinct lineages, at least one of the proposed splits, while not a distinct family, might be a valid subfamily.
Arhynchobdellida, the proboscisless leeches, are a monophyletic order of leeches. They are defined by the lack of the protrusible proboscis that defines their sister taxon, the Rhynchobdellida. Arhynchobdellida is a diverse order, compromising both aquatic and terrestrial, besides sanguivorous and predatory, leeches. The order is divided into two suborders, Erpobdelliformes and Hirudiniformes.
The Hirudiniformes are one of the currently-accepted suborders of the proboscisless leeches (Arhynchobdellida). Their best-known member is the European medical leech, Hirudo medicinalis, and indeed most of the blood-sucking "worms" as which leeches are generally perceived belong to this group. In general, though some leeches suck blood, many are predators which hunt small invertebrates.
Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodies that can lengthen and contract. Both groups are hermaphrodites and have a clitellum, but leeches typically differ from the oligochaetes in having suckers at both ends and in having ring markings that do not correspond with their internal segmentation. The body is muscular and relatively solid, and the coelom, the spacious body cavity found in other annelids, is reduced to small channels.
Xerobdellidae are a small family of jawed leeches in the order Arhynchobdellida. Xerobdellidae have three jaws and five pairs of eyes, the fourth and fifth being separated by one or two eyeless segments. The genera placed herein occur in Chile (Mesobdella), Europe (Xerobdella) and Diestecostoma is found in Central and northern South America. This peculiar distribution strongly suggests they are a relict Pangaean group, which had already been present by the start of the Jurassic 250 million years ago.
Phytobdella catenifera is a large terrestrial leech found in Peninsular Malaysia. John Percy Moore chose this species’ epithet ‘catenifera’ after the striking chain-striped pattern on the creature's back.
Americobdella is a genus of carnivorous leeches from southern Chile, comprising only the species, Americobdella valdiviana.
Erpobdella is a genus of leeches in the family Erpobdellidae. Members of the genus have three or four pairs of eyes, but never have true jaws, and are typically 20–50 millimetres (0.8–2.0 in) long. All members do not feed on blood, but instead are predators of small aquatic invertebrates, which they often swallow whole.
Branchiobdellida is an order of freshwater leech-like clitellates that are obligate ectosymbionts or ectoparasites, mostly of astacoidean crayfish. They are found in the Northern Hemisphere and have a holarctic distribution in East Asia, the Euro-Mediterranean region and North and Central America, with the greatest species diversity being in North and Central America.
Erpobdellidae is a family of leeches. It is one of the four families belonging to the suborder Erpobdelliformes of the proboscisless leeches order, Arhynchobdellida.
The annelids, also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments.
Erpobdella octoculata is a freshwater leech in the Erpobdellidae family. This species can be found in Europe, the Mediterranean, and the Middle East.
Acanthobdella peledina is a species of leech-like clitellate in the order Acanthobdellida. It feeds on the skin and blood of freshwater fishes in the boreal regions of northern Europe, Asia and North America.
Placobdelloides is a genus of glossophoniid leeches.
Acanthobdellidea is an infraclass of primitive leeches; some authors place them in a separate subclass from the Hirudinea. However, the World Register of Marine Species places them within the Hirudinea, as a sister group to Euhirudinea, the true leeches.
Limnatis nilotica is a species of leech in the family Hirudinidae. It is hematophagous, living on the mucous membranes of mammals.
Dinobdella ferox is a species of leech in the family Praobdellidae. The species is found widely in Southeast Asia and mainly feeds on the mucosal membranes of the mammalian upper respiratory tract. It has been documented to feed on humans.
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