The Hirudiniformes are one of the currently-accepted

suborder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

s of the proboscisless

leech 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 bodie ...

es (

Arhynchobdellida 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.Uttam, Suneha, and Seema Langer.Distribution and Ide ...

). Their best-known member is the

European medical leech ''Hirudo medicinalis'', the European medicinal leech, is one of several species of leeches used as "medicinal leeches". Other species of ''Hirudo'' sometimes also used as medicinal leeches include ''Hirudo orientalis, H. orientalis'', ''H. troc ...

, ''Hirudo medicinalis'', and indeed most of the blood-sucking "

worm Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always). Worms vary in size from microscopic to over in length for marine polychaete wor ...

s" as which leeches are generally perceived belong to this group. In general, though some leeches suck blood, many are

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

s which hunt small

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

Taxonomy

"Jawed leeches" - termed "Gnathobdellae" or "Gnathobdellida" - are exclusively found among the Hirudiniformes, but the order contains a number of jawless

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

as well. The jawed, toothed forms make up the aquatic Hirudidae and the

terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...

Haemadipsidae __NOTOC__ Haemadipsidae (From Greek "haima" and "dipsa" ("blood" and "thirst", respectively)) are a family of jawed leeches. They are a monophyletic group of hirudiniform proboscisless leeches. These leeches have five pairs of eyes, with the l ...

and

Xerobdellidae 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 ( ...

(sometimes included in the preceding but worthy of recognition as an independent family). These might actually form a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

, which would then be placed at superfamily rank,The

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

would thus become "Gnathobdelloidea" according to

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...

rules, but the issue has neither been sufficiently studied nor formally proposed. but it seems that the Hirudidae might rather be close relatives of the

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

Haemopidae instead. (2008): On the classification, evolution and biogeography of terrestrial haemadipsoid leeches (Hirudinida: Arhynchobdellida: Hirudiniformes). '' Mol. Phylogenet. Evol.'' 46(1): 142–154. (HTML abstract) Many of the most well-known leeches belong to this family, most notably the medical leeches, such as the European

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

, already mentioned, which is prominent among these. Other medical Hirudiniformes of lesser importance are for example other species of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Hirudo ''Hirudo'' is a genus of leeches of the family Hirudinidae. It was described by Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a ...

'', the North American medical leech ('' Macrobdella decora''), and the Asian medical leech ('' Hirudinaria manillensis''). Among the better-known bloodsucking land leeches are species belonging to the Asian genus '' Haemadipsa'': they include the Indian leech (''H. sylvestris'') and the ''yamabiru'' or Japanese Mountain Leech (''H. zeylanica'').

References & footnotes

{{Taxonbar, from=Q5771852 Leeches Protostome suborders