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 Pentastomida are an enigmatic group of parasitic arthropods commonly known as tongue worms due to the resemblance of the species of the genus Linguatula to a vertebrate tongue; molecular studies point to them being highly-derived crustaceans.
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.
Haemogregarina is a genus of haemoprotozoans, parasitic mainly on cold-blooded vertebrates. They are unicellular organisms which are parasitic in the red blood cells. Haemogregarina infects lower vertebrates as intermediate hosts and leeches.
The Cymothoidae are a family of isopods in the suborder Cymothoida found in both marine and freshwater environments. Cymoithoids are ectoparasites, usually of fish, and they include the bizarre "tongue-biter", which attaches to a fish's tongue, causing it to atrophy, and replaces the tongue with its own body. Ceratothoa oestroides is one of the most devastating ectoparasites in Mediterranean aquaculture. Around 40 genera and more than 380 species of cymothoid are recognised. Species of the Cymothoidae are generally found in warmer waters and rarely in the cool and cold climates.
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 ring markings that do not correspond with their internal segmentation. The body is muscular and relatively solid; the coelom, the spacious body cavity found in other annelids, is reduced to small channels.
Hirudo verbana is a species of leech.
Hemibdella soleae is a marine species of leech in the family Piscicolidae and the type taxon of its genus. Found in the northeastern Atlantic Ocean, it is a parasite of flatfish such as the common sole.
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.
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.
Anna J. Phillips is an American Research Zoologist and curator of Clitellata and Cestoda at the National Museum of Natural History's Department of Invertebrate Zoology. As a parasitologist her research focuses on leeches and tapeworms, by studying their diversity, relationships, and host associations. She has traveled all over the world with her fieldwork to study the diversity of these invertebrates on a long range.
Microcotyle donavini is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae.
Microcotyle toba is a species of monogenean, parasitic on the gills of a marine fish. It belongs to the family Microcotylidae.
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.
Mark E. Siddall is a Canadian biologist and former curator at the American Museum of Natural History. Siddall has studied the evolution and systematics of blood parasites and leeches, and systematic theory. Siddall was hired as an assistant curator at the American Museum of Natural History in July, 1999 and worked there as a curator until September, 2020, when he was terminated for allegedly having violated the museum's policy prohibiting sexual relationships between staff and mentees. Siddall denied the claim.
Trachelobdella lubrica is a species of marine leech in the family Piscicolidae. It is a parasite of fish and has a worldwide distribution in the equatorial belt. It was first described in 1840 by the German zoologist Adolph Eduard Grube, the type locality being Palermo, Sicily, in the Mediterranean Sea.
Cystobranchus is a monotypic genus of annelids belonging to the family Piscicolidae. The species of this genus are found in Europe and Northern America. The World Register of Marine Species accepts one species within Cystobranchus. Cystobranchus is also known as a leech, and it is a freshwater leech, usually found in revisers, streams, lakes, and ponds across North America. They often attach themselves on the external part of freshwater fish and feed on their blood. In doing so, a possible process of infestation could occur causing the fish to be more suspectable to stressors and diseases. E. M., Light, J. E., & Williams, J. I. (2005). Redescription of Cystobranchus virginicus Hoffman, 1964, and Cystobranchus salmositicus from Freshwater Fishes in North America. Comparative Parasitology, 72(2), 157–165. https://doi.org/10.1654/4161/
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.
Pontobdella californiana is a species of marine leech found off the southern Pacific coast of North America. They are relatively large, greenish, tubercle-covered leeches who parasitize skates and rays. The species was scientifically described in 2015 based on previously-collected specimens and has since been recorded elsewhere.
Pontobdella is a species of marine leeches with a cosmopolitan distribution. They are covered with tubercles and their primary hosts are rays, sharks, skates, and sawfish.
