Arhynchobdellida, the proboscisless leeches, are a monophyletic

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

leeches Leeches are segmented parasitism, parasitic or Predation, predatory worms that comprise the Class (biology), subclass Hirudinea within the phylum Annelida. They are closely related to the Oligochaeta, oligochaetes, which include the earthwor ...

. They are defined by the lack of the protrusible proboscis that defines their sister taxon, the

Rhynchobdellida Rhynchobdellida (from the Greek ''rhynchos'', mouth, and ''bdellein'', sucking), 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 wa ...

.Uttam, Suneha, and Seema Langer.
Distribution and Identification key for species of freshwater leech genus Erpobdella Blainville, 1818 (Hirudinida: Arhynchobdellida: Erpobdelliformes: Erpobdellidae)."
/ref> Arhynchobdellida is a diverse order, comprimising both aquatic and

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 ...

, besides sanguivorous and

predatory 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 ...

, leeches. The order is divided into two suborders,

Erpobdelliformes The Erpobdelliformes are one of the currently-accepted suborders of the proboscisless leeches (Arhynchobdellida). It includes five families: * Americobdellidae * Erpobdellidae Blanchard, 1894 * Gastrostomobdellidae Richardson, 1971 *Orobdellid ...

and Hirudiniformes (sometimes also called the Pharyngobdelliformes and Gnathobdelliformes, respectively).

Taxonomy

Historically, the Arhynchobdellida were split into two orders, the Gnathobdellida and the Pharyngobdellida. The Gnathobdellida were jawed and carnivorous of parasitic while the Pharyngobdellida were jawless and carnivorous. Current taxonomy accepts the order Arhynchobdellida and divides into two suborders. There are 215 species of Arhynchobdellid leech, in 47 genera and 13 families. The placement of Americobdellidae is uncertain; it has rudimentary jaws and is terrestrial. Achtäugiger Roll Egel

Erpobdelliformes

are jawless predators of aquatic invertebrates of varying sizes, including insect larvae, mollusks, and other annelids. Unlike other leeches, they do not penetrate the skin of hosts; and are not at all parasitic. The

pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...

is spirally twisted and very large to allow for large prey; it can constitute up to one third of the leech's body length. Haemadipsa zeylanica japonica 0s1

Taxonomy

Erpobdelliformes

Hirudiniformes

Cladogram

References