| Macrostomidae | |
|---|---|
 | |
| An adult Antromacrostomum armatum | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Platyhelminthes |
| Order: | Macrostomida |
| Family: | Macrostomidae |
| Genera | |
Macrostomidae [1] is a family of small basal free-living flatworms, and are found in marine, brackish, and freshwater environments. [1] There are currently about 180 named species in this family. [2]
Species of the family Macrostomidae are small (~0.5 to 5 mm in length) and generally highly transparent microturbellarians. They are usually round in cross section, and with only the largest forms being dorso-ventrally flattened. They are distinguished from related animals by the possession of a simple pharynx and intestine, a single pair of lateral nerve cords, and by the absence of a statocyst. [2]
Species of the family Macrostomidae are members of a large range of aquatic faunas, ranging from the meiobenthos, epibenthos, to plankton. Moreover, they occur in marine, brackish, and freshwater habitats, and many forms are particularly abundant in the intertidal meiobenthos, where they can be exposed to highly variable environmental conditions. There are also many sub-tidal and a few deep-sea forms. They can be found in all major bodies of water worldwide, and in the freshwater of all continents, except Antarctica.
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater and fresh water together, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root brak. Certain human activities can produce brackish water, in particular civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming. Brackish water is also the primary waste product of the salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment.
Tetraodontidae is a family of primarily marine and estuarine fish of the order Tetraodontiformes. The family includes many familiar species variously called pufferfish, puffers, balloonfish, blowfish, blowers, blowies, bubblefish, globefish, swellfish, toadfish, toadies, toadle, honey toads, sugar toads, and sea squab. They are morphologically similar to the closely related porcupinefish, which have large external spines.
The gastrotrichs, commonly referred to as hairybellies or hairybacks, are a group of microscopic (0.06–3.0 mm), cylindrical, acoelomate animals, and are widely distributed and abundant in freshwater and marine environments. They are mostly benthic and live within the periphyton, the layer of tiny organisms and detritus that is found on the seabed and the beds of other water bodies. The majority live on and between particles of sediment or on other submerged surfaces, but a few species are terrestrial and live on land in the film of water surrounding grains of soil. Gastrotrichs are divided into two orders, the Macrodasyida which are marine, and the Chaetonotida, some of which are marine and some freshwater. Nearly 800 species of gastrotrich have been described.
Gastropods, commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda.
Meiobenthos, also called meiofauna, are small benthic invertebrates that live in marine or freshwater environments, or both. The term meiofauna loosely defines a group of organisms by their size—larger than microfauna but smaller than macrofauna—rather than by their taxonomy. This fauna includes both animals that turn into macrofauna later in life, and those small enough to belong to the meiobenthos their entire life. In marine environments there can be thousands of individuals in 10 cubic centimeters of sediment, and counts animals like nematodes, copepods, rotifers, tardigrades and ostracods, but protists like ciliates and foraminifers within the size range of the meiobethos are also often included. In practice, the term usually includes organisms that can pass through a 1 mm mesh but are retained by a 45 μm mesh, though exact dimensions may vary. Whether an organism will pass through a 1 mm mesh also depends upon whether it is alive or dead at the time of sorting.
The Turbellaria are one of the traditional sub-divisions of the phylum Platyhelminthes (flatworms), and include all the sub-groups that are not exclusively parasitic. There are about 4,500 species, which range from 1 mm (0.039 in) to large freshwater forms more than 500 mm (20 in) long or terrestrial species like Bipalium kewense which can reach 600 mm (24 in) in length. All the larger forms are flat with ribbon-like or leaf-like shapes, since their lack of respiratory and circulatory systems means that they have to rely on diffusion for internal transport of metabolites. However, many of the smaller forms are round in cross section. Most are predators, and all live in water or in moist terrestrial environments. Most forms reproduce sexually and with few exceptions all are simultaneous hermaphrodites.
Thymallus or graylings is a genus of freshwater salmonid ray-finned fish and the only genus within the subfamily Thymallinae. Although all Thymallus species can be generically called graylings, without specific qualification the term "grayling" typically refers to the type species Thymallus thymallus, the European grayling.
Hemichromis is a genus of fishes from the cichlid family, known in the aquarium trade as jewel cichlids. Jewel cichlids are native to Africa. Within West Africa, Hemichromis species are found in creeks, streams, rivers and lakes with a variety of water qualities including brackish water lagoons. As traditionally defined, the genus includes two distinctly different groups: The five-spotted cichlid group and the true jewel cichlid group (Rubricatochromis), which sometimes are recognized as distinct genera.
The Ariidae or ariid catfish are a family of catfish that mainly live in marine waters with many freshwater and brackish water species. They are found worldwide in tropical to warm temperate zones. The family includes about 143 species.
The Pacific ladyfish, also known as the Pacific tenpounder and machete, is a species of ray-finned fish in the genus Elops, the only genus in the monotypic family Elopidae. The Pacific ladyfish can be found throughout the southwest U.S. and other areas in the Pacific Ocean.
Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the absence of a visible shell.
Theodoxus fluviatilis, common name the river nerite, is a species of small freshwater and brackish water snail with a gill and an operculum, an aquatic gastropod mollusk in the family Neritidae, the nerites.
Eels are ray-finned fish belonging to the order Anguilliformes, which consists of eight suborders, 20 families, 164 genera, and about 1000 species. Eels undergo considerable development from the early larval stage to the eventual adult stage and are usually predators.
Acochlidiacea, common name acochlidians, are a taxonomic clade of very unusual sea snails and sea and freshwater slugs, aquatic gastropod mollusks within the large clade Heterobranchia. Acochlidia is a variant spelling.
Freshwater snails are gastropod mollusks that live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs to major rivers. The great majority of freshwater gastropods have a shell, with very few exceptions. Some groups of snails that live in freshwater respire using gills, whereas other groups need to reach the surface to breathe air. In addition, some are amphibious and have both gills and a lung. Most feed on algae, but many are detritivores and some are filter feeders.
The Dolichomacrostomidae are a family of small basal free-living flatworms, and members of the marine, but also brackish, meiobenthos. The name was coined by Reinhard M. Rieger (1971), who designated the Dolichomacrostomidae as a family within the taxon Macrostomida. There are currently about 40 named species in this family.
The Microstomidae are a family of small basal free-living flatworms, and members of the marine, brackish, freshwater meiobenthos and plankton. There are currently about 40 named species in this family.
Macrostomum rostratum is a free-living, hermaphroditic flatworm in the family Macrostomidae, found in freshwater and brackish environments.
Cyclotella is a genus of diatoms often found in oligotrophic environments, both marine and fresh water. It is in the family Stephanodiscaceae and the order Thalassiosirales. The genus was first discovered in the mid-1800s and since then has become an umbrella genus for nearly 100 different species, the most well-studied and the best known being Cyclotella meneghiniana. Despite being among the most dominant genera in low-productivity environments, it is relatively understudied.
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