Malacostraca is the largest of the six classes of crustaceans, containing about 40,000 living species, divided among 16 orders. Its members, the malacostracans, display a great diversity of body forms and include crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, amphipods, mantis shrimp, tongue-eating lice and many other less familiar animals. They are abundant in all marine environments and have colonised freshwater and terrestrial habitats. They are segmented animals, united by a common body plan comprising 20 body segments, and divided into a head, thorax, and abdomen.
Oligochaeta is a subclass of animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms. Specifically, oligochaetes comprise the terrestrial megadrile earthworms, and freshwater or semiterrestrial microdrile forms, including the tubificids, pot worms and ice worms (Enchytraeidae), blackworms (Lumbriculidae) and several interstitial marine worms.
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.
Erpobdella obscura is a freshwater ribbon leech common in North America. It is a relatively large leech and is commonly used as bait by anglers for walleye and other sport fish. In Minnesota, live bait dealers annually harvest over 45,000 kg of bait-leeches, raising concerns of over-harvest.
Triops longicaudatus is a freshwater crustacean of the order Notostraca, resembling a miniature horseshoe crab. It is characterized by an elongated, segmented body, a flattened shield-like brownish carapace covering two thirds of the thorax, and two long filaments on the abdomen. The genus name Triops comes from Ancient Greek ὤψ or ṓps, meaning "eye" prefixed with Latin tri-, "three", in reference to its three eyes. Longicaudatus is a Latin neologism combining longus ("long") and caudatus ("tailed"), referring to its long tail structures. Triops longicaudatus is found in freshwater ponds and pools, often in places where few higher forms of life can exist.
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.
Motobdella montezuma is a species of leech which is only found in Montezuma Well, central Arizona, United States. It is a nocturnal pelagic predator that feeds almost exclusively on the endemic amphipod Hyalella montezuma, which it detects using passive sonar and swallows whole.
A sucker in zoology refers to a specialised attachment organ of an animal. It acts as an adhesion device in parasitic worms, several flatworms, cephalopods, certain fishes, amphibians, and bats. It is a muscular structure for suction on a host or substrate. In parasitic annelids, flatworms and roundworms, suckers are the organs of attachment to the host tissues. In tapeworms and flukes, they are a parasitic adaptation for attachment on the internal tissues of the host, such as intestines and blood vessels. In roundworms and flatworms they serve as attachment between individuals particularly during mating. In annelids, a sucker can be both a functional mouth and a locomotory organ. The structure and number of suckers are often used as basic taxonomic diagnosis between different species, since they are unique in each species. In tapeworms there are two distinct classes of suckers, namely "bothridia" for true suckers, and "bothria" for false suckers. In digeneal flukes there are usually an oral sucker at the mouth and a ventral sucker posterior to the mouth. Roundworms have their sucker just in front of the anus; hence it is often called a pre-anal sucker.
Haemopis sanguisuga is a species of freshwater leech in the family Haemopidae. It is commonly called the horse-leech, but that is due to the similarity of its appearance to the leech Limnatis nilotica, which sometimes enters the nasal cavities of livestock. Haemopis sanguisuga does not behave in this way. Another synonym for this leech is Aulastomum gulo.
Crustaceans belong to the subphylum Crustacea,, and form a large, diverse group of arthropods including decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. Some crustaceans are more closely related to insects and the other hexapods than they are to certain other crustaceans.
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.
Hirudo orientalis is a species of medicinal leech. It has been confused with Hirudo medicinalis, but has recently been recognized as a different species. This Asian species is associated with mountainous areas in the subboreal eremial zone and occurs in Azerbaijan, Iran, Uzbekistan and Kazakhstan. It occurs also in Georgia, and probably in Armenia.
Erpobdella octoculata is a freshwater leech in the Erpobdellidae family. This species can be found in Europe, the Mediterranean, and the Middle East.
Erpobdella punctata is a leech in the family Erpobdellidae. It is found in freshwater streams and ponds in many parts of North America.
The Piscicolidae are a family of jawless leeches in the order Rhynchobdellida that are parasitic on fish. They occur in both freshwater and seawater, have cylindrical bodies, and typically have a large, bell-shaped, anterior sucker with which they cling to their host. Some of the leeches in this family have external gills, outgrowths of the body wall projecting laterally, the only group of leeches to exchange gases in this way.
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.
Barbronia weberi is a species of predatory freshwater leech in the family Salifidae. It is native to southeastern Asia but has spread to other parts of the world, including Australia, South America, southern Europe and the United States.
Myzobdella lugubris, the crab leech, is a species of jawless leech widespread in North America, especially in central and Eastern Canada. It is an ectoparasite of fish and crustaceans, and is responsible for several dangerous conditions in fish, including lesions infected by bacteria and fungi and possibly viral hemorrhagic septicemia. It lays its egg capsules on crabs and possible other arthropods, which then disperse the eggs.
