| Theromyzon tessulatum | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Class: | Clitellata |
| Subclass: | Hirudinea |
| Order: | Rhynchobdellida |
| Family: | Glossiphoniidae |
| Genus: | Theromyzon |
| Species: | T. tessulatum |
| Binomial name | |
| Theromyzon tessulatum (O. F. Müller, 1774) [1] | |
Theromyzon tessulatum is a species of leech in the family Glossiphoniidae. It is a haematophagous (blood-sucking) leech, found in freshwater habitats in Europe.
The cuticle of T. tessulatum is transparent, olive green or brownish in colour, with larger individuals often exhibiting six longitudinal rows of small yellow spots. This leech is active and frequently changes shape, being up to 6 cm (2.4 in) long when extended. The posterior sucker is broad and conspicuous but the anterior sucker is small, and invisible when the animal is viewed from above. [2]
This leech is found in freshwater habitats in Europe. [3] It is common in the coastal flat parts of Holland which are visited by the waterfowl that act as its hosts. [1] It is uncommon in Britain, where it has a discontinuous range, probably being distributed by movements of its bird hosts. [2] It has also been recorded in North America from a number of locations. [3]
When parasitizing ducks and other waterfowl, T. tessulatum invades their mouths and respiratory passages. At other times, it is free-living in freshwater habitats. The adult broods its egg capsules on its under surface, where there may be as many as two hundred eggs. [2] When the young are ready to emerge, the adult uses its sensilla organs to detect vibrations in the water and will move towards any disturbance that might be caused by a potential host. Suitable hosts are those with body temperatures of between 37 and 40 °C (99 and 104 °F). Although generally nocturnal and negatively phototactic (avoiding light), when the brooding adult is ready to release its young, it may swim in open water in the middle of the day. [3] If it finds a suitable host, it attaches itself with its sucker to the nasal passages, the respiratory tract or inside the mouth. [1] This leech is unique in that the adult attaches to the host but does not itself feed on it; instead, the young that it was brooding transfer to the host to take their first blood meal. [3]
The flatworms, flat worms, Platyhelminthes, or platyhelminths are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates. Unlike other bilaterians, they are acoelomates, and have no specialised circulatory and respiratory organs, which restricts them to having flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. The digestive cavity has only one opening for both ingestion and egestion ; as a result, the food cannot be processed continuously.
Trematoda is a class of flatworms known as flukes or trematodes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive host, where the flukes sexually reproduce, is a vertebrate. Infection by trematodes can cause disease in all five traditional vertebrate classes: mammals, birds, amphibians, reptiles, and fish.
Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this pouch and are not free-swimming characterises the order. The mysid's head bears a pair of stalked eyes and two pairs of antennae. The thorax consists of eight segments each bearing branching limbs, the whole concealed beneath a protective carapace and the abdomen has six segments and usually further small limbs.
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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 longnose sucker is a species of cypriniform freshwater fish in the family Catostomidae. It is native to North America from the northern United States to the top of the continent. It is also found in Russia in rivers of eastern Siberia, and thus one of only two species of sucker native to Asia.
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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.
Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, to spawn refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquatic mammals and reptiles, reproduce through the process of spawning.
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.
Eustrongylidosis is a parasitic disease that mainly affects wading birds worldwide; however, the parasite's complex, indirect lifecycle involves other species, such as aquatic worms and fish. Moreover, this disease is zoonotic, which means the parasite can transmit disease from animals to humans. Eustrongylidosis is named after the causative agent Eustrongylides, and typically occurs in eutrophicated waters where concentrations of nutrients and minerals are high enough to provide ideal conditions for the parasite to thrive and persist. Because eutrophication has become a common issue due to agricultural runoff and urban development, cases of eustrongylidosis are becoming prevalent and hard to control. Eustrongylidosis can be diagnosed before or after death by observing behavior and clinical signs, and performing fecal flotations and necropsies. Methods to control it include preventing eutrophication and providing hosts with uninfected food sources in aquaculture farms. Parasites are known to be indicators of environmental health and stability, so should be studied further to better understand the parasite's lifecycle and how it affects predator-prey interactions and improve conservation efforts.
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.
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.
Polystoma integerrimum is a flatworm (platyhelminth) from the class Monogenea found in amphibians in Asia and Europe. It is an endoparasite of frogs and toads and has an unusual life cycle which synchronises with that of its host.
Piscicola geometra is a species of leech in the family Piscicolidae. It is an external parasite of marine, brackish and freshwater fishes. It was first described as Hirudo geometra by the Swedish naturalist Carl Linnaeus in his Systema Naturae in 1758.
Pontobdella muricata is a species of marine leech in the family Piscicolidae. It is a parasite of fishes and is native to the northeastern Atlantic Ocean, the Baltic Sea, the North Sea, and the Mediterranean Sea.
Limnatis nilotica is a species of leech in the family Hirudinidae. It is hematophagous, living on the mucous membranes of mammals.
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.
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.