The Percopsiformes are a small order of freshwater teleost fishes measuring less than 20 cm in length, comprising the trout-perch and its allies. It contains just ten extant species, grouped into seven genera and three families. Five of these genera are monotypic.
Centrarchidae, better known as sunfishes, is a family of freshwater ray-finned fish belonging to the order Centrarchiformes, native only to North America. There are eight universally included genera within the centrarchid family: Lepomis, Micropterus, Pomoxis (crappies), Enneacanthus, Centrarchus, Archoplites, Ambloplites, and Acantharchus. A genetic study in 2012 suggests that the highly distinct pygmy sunfishes of the genus Elassoma are also centrarchids.
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 Unionidae are a family of freshwater mussels, the largest in the order Unionida, the bivalve molluscs sometimes known as river mussels, or simply as unionids.
Physidae, commonly called the bladder snails, is a family of small air-breathing freshwater snails, aquatic pulmonate gastropod molluscs in the superfamily Lymnaeoidea.
Unionida is a monophyletic order of freshwater mussels, aquatic bivalve molluscs. The order includes most of the larger freshwater mussels, including the freshwater pearl mussels. The most common families are the Unionidae and the Margaritiferidae. All have in common a larval stage that is temporarily parasitic on fish, nacreous shells, high in organic matter, that may crack upon drying out, and siphons too short to permit the animal to live deeply buried in sediment.
The red stingray is a species of stingray in the family Dasyatidae, found in the northwestern Pacific Ocean off Japan, Korea, and China, and possibly elsewhere. It primarily inhabits shallow, sandy habitats close to shore, and has been known to enter brackish water. The red stingray has a diamond-shaped pectoral fin disc and gains its common name from its bright orange-red underside; there may also be patches of orange at various spots on its upper surface. Most individuals are no more than 1 m (3.3 ft) long.
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.
The cowtail stingray is a species of stingray in the family Dasyatidae, widespread in the Indo-Pacific region and occasionally entering freshwater habitats. Other common names include banana-tail ray, drab stingray, fantail ray, feathertail stingray, and frill tailed sting ray. This species is sometimes placed in the genus Dasyatis or Hypolophus. The most distinctive characteristic of the cowtail stingray is the large, flag-like ventral fold on its tail, which is especially prominent when the ray is swimming. This species is targeted by commercial fisheries as a source of high-quality shagreen, a type of leather, and its populations are now under threat from heavy exploitation.
Babesiosoma is a genus of parasitic alveolates in the phylum Apicomplexia.
Placobdella parasitica is a species of leech found in North America. Leeches are habitual ectoparasites of vertebrates in aquatic environments. Placobdella parasitica is differentiated from other members of the genus Placobdella by its smooth dorsal surface, simple to complicated pigmentation, and abdomen with 8 to 12 stripes.
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.
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.
Philobdella is a genus of Nearctic leeches belonging to the family Macrobdellidae.
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.
Macrobdella decora, also known as the North American medicinal leech, is a species of freshwater leech found in much of eastern North America in freshwater habitats, although there is one disjunct population in northern Mexico. M. decora is both a parasite of vertebrates, including humans, and an aquatic predator of eggs, larvae, and other invertebrates. Macrobdella decora is a medium-sized leech with a spotted greenish-brown back and a reddish underbelly. It has ten ocelli, or simple eyes, arranged in a horseshoe shape, as well as three long jaws. Internally, a pharynx takes up a tenth of its digestive tract; a stomach, the majority of its body length. The stomach connects to an intestine, followed by a colon, a rectum, and finally an anus located on the leech's back. M. decora, like all leeches, is hermaphroditic, and has ten testisacs and two ovisacs, in addition to male and female genital pores. First described by Thomas Say in 1824, the species is now placed in the genus Macrobdella. Its sister taxon is believed to be the species Macrobdella diplotertia.
