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Apteronotid
The ghost knifefishes consist of the family Apteronotidae, which are ray-finned fishes in the order Gymnotiformes. These fish are native to Panama and South America. They inhabit a wide range of freshwater habitats, but more than half the species in the family are found deep in rivers (typically deeper than ) where there is little or no light. The genus ''Apteronotus'' is "artificial" and some of the species do not actually belong in it; it is polyphyletic. They are distinguished from other gymnotiform fishes by the presence of a caudal fin (all other families lack a caudal or tail fin) as well as a fleshy Dorsal (anatomy), dorsal organ represented by a longitudinal strip along the dorsal midline. They vary greatly in size, ranging from about in total length in the smallest species to in the largest. It has been claimed that ''Apteronotus magdalenensis'' is up to , but this is not supported by recent studies, which indicate that it does not surpass about . These nocturnal fish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sternarchogiton Nattereri
''Sternarchogiton nattereri'' is a species of weakly electric fish, weakly electric Gymnotiformes, knifefish in the family Apteronotidae. It is native to the Amazon basin, Amazon River system and feeds on sponges. Unlike other members of the genus ''Sternarchogiton'', there is pronounced sexual dimorphism in ''S. nattereri'', with reproductively mature males developing strong external teeth on tips of their jaws. These males are so different from the females and juvenile (organism), juveniles that they were thought to be a different genus and species, the "tooth-lip knifefish" ''Oedemognathus exodon'', for over 40 years. Distribution and habitat ''S. nattereri'' is restricted to large river channels in the lowlands of the Amazon basin. Its habitat ranges from high-Electrical conductivity, conductivity, sediment-rich Whitewater river (river type), whitewater rivers such as the Rio Solimões, to low-conductivity, sediment-poor blackwater river, blackwaters such as the Rio Negro (Ama ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnotiformes
The Gymnotiformes are an order of teleost bony fishes commonly known as Neotropical knifefish or South American knifefish. They have long bodies and swim using undulations of their elongated anal fin. Found almost exclusively in fresh water (the only exceptions are species that occasionally may visit brackish water to feed), these mostly nocturnal fish are capable of producing electric fields to detect prey, for navigation, communication, and, in the case of the electric eel (''Electrophorus electricus''), attack and defense. A few species are familiar to the aquarium trade, such as the black ghost knifefish (''Apteronotus albifrons''), the glass knifefish (''Eigenmannia virescens''), and the banded knifefish (''Gymnotus carapo''). Description Anatomy and locomotion Aside from the electric eel (''Electrophorus electricus''), Gymnotiformes are slender fish with narrow bodies and tapering tails, hence the common name of "knifefishes". They have neither pelvic fins nor d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sternarchella
''Sternarchella'', the bulldog knifefishes, is a genus of ghost knifefishes found at depths of in the main channel of large rivers in South America. Most are from the Amazon basin, but ''S. orthos'' is found both in the Amazon and Orinoco, ''S. orinoco'' is restricted to the Orinoco and ''S. curvioperculata'' restricted to the upper Paraná basin (however, the last species likely belongs in another genus, possibly ''Apteronotus''). They are often common in their habitat.Lundberg, J.G., Cox Fernandes, C., Campos-Da-Paz, R. & Sullivan, J.P. (2013): ''Sternarchella calhamazon'' n. sp., the Amazon’s most abundant species of apteronotid electric fish, with a note on the taxonomic status of ''Sternarchus capanemae'' Steindachner, 1868 (Gymnotiformes, Apteronotidae). ''Proceedings of the Academy of Natural Sciences of Philadelphia, 162: 157-173.'' They have a blunt or pointed snout (none have the greatly elongated snout found in some other knifefish), reduced pigmentation and reach ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Ghost Knifefish
The black ghost knifefish (''Apteronotus albifrons'') is a tropical fish belonging to the ghost knifefish Family (biology), family (Apteronotidae). They originate in freshwater habitats in South America where they range from Venezuela to the Paraguay River, Paraguay–Paraná River, including the Amazon Basin. They are popular in aquarium, aquaria. The fish is all black except for two white rings on its tail, and a white blaze on its nose, which can occasionally extend into a stripe down its back. It moves mainly by undulating a long fin on its underside. It will grow to a length of . Black ghost knifefish are Nocturnality, nocturnal. They are a weakly electric fish which use an Electric organ (biology), electric organ and receptors distributed over the length of their body in order to locate prey, including insect larvae.Nelson M. E. & MacIver M. A. (1999). "Prey capture in the weakly electric fish ''Apteronotus albifrons'': sensory acquisition strategies and electrosensory conse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Organ Discharge
An Torpediniformes.html" ;"title="electric ray (Torpediniformes">electric ray (Torpediniformes) showing location of paired electric organs in the head, and electrocytes stacked within it In biology, the electric organ is an organ (biology), organ that an electric fish uses to create an electric field. Electric organs are derived from modified muscle or in some cases nerve tissue, called electrocytes, and have evolved at least six times among the Elasmobranchii, elasmobranchs and teleosts. These fish use their electric discharges for navigation, communication, mating, defence, and in strongly electric fish also for the incapacitation of prey. The electric organs of two strongly electric fish, the torpedo ray and the electric eel, were first studied in the 1770s by John Walsh, Hugh Williamson, and John Hunter. Charles Darwin used them as an instance of convergent evolution in his 1859 ''On the Origin of Species''. Modern study began with Hans Lissmann's 1951 study of electr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales. Marine plankton include bacteria, archaea, algae, protozoa, microscopic fungi, and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. fresh water, Freshwater plankton are similar to marine plankton, but are found in lakes and rivers. Mostly, plankton just drift where currents take them, though some, like jellyfish, swim slowly but not fast enough to generally overcome the influence of currents. Although plankton are usually thought of as inhabiting water, there are also airborne versions that live part of their lives drifting in the at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large Woody Debris
Large woody debris (LWD) are the logs, sticks, branches, and other wood that falls into streams and rivers. This debris can influence the flow and the shape of the stream channel. Large woody debris, grains, and the shape of the bed of the stream are the three main providers of flow resistance, and are thus a major influence on the shape of the stream channel. Some stream channels have less LWD than they would naturally because of removal by watershed managers for flood control and aesthetic reasons. The study of woody debris is important for its forestry management implications. Plantation thinning can reduce the potential for recruitment of LWD into proximal streams. The presence of large woody debris is important in the formation of pools which serve as salmon habitat in the Pacific Northwest. Entrainment of the large woody debris in a stream can also cause erosion and scouring around and under the LWD. The amount of scouring and erosion is determined by the ratio of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porifera
Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a Basal (phylogenetics) , basal clade and a sister taxon of the Eumetazoa , diploblasts. They are sessility (motility) , sessile filter feeders that are bound to the seabed, and are one of the most ancient members of macrobenthos, with many historical species being important sponge reef , reef-building organisms. Sponges are multicellular organisms consisting of jelly-like mesohyl sandwiched between two thin layers of cell (biology) , cells, and usually have tube-like bodies full of pores and channels that allow water to circulate through them. They have unspecialized cells that can cellular differentiation , transform into other types and that often migrate between the main cell layers and the mesohyl in the process. They do not have complex nervous system , nervous, digestive system , digestive or circulatory systems. Instead, most rely on maintaining a constant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthos
Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.Benthos from the Census of Antarctic Marine Life website This community lives in or near marine or freshwater sedimentary environments, from tidal pools along the , out to the continental shelf, and then down to the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Bed
A streambed or stream bed is the bottom of a stream or river and is confined within a channel or the banks of the waterway. Usually, the bed does not contain terrestrial (land) vegetation and instead supports different types of aquatic vegetation (aquatic plant), depending on the type of streambed material and water velocity. Streambeds are what would be left once a stream is no longer in existence. The beds are usually well preserved even if they get buried because the banks and canyons made by the stream are typically hard, although soft sand and debris often fill the bed. Dry, buried streambeds can actually be underground water pockets. During times of rain, sandy streambeds can soak up and retain water, even during dry seasons, keeping the water table close enough to the surface to be obtainable by local people. The nature of any streambed is always a function of the flow dynamics and the local geologic materials. The climate of an area will determine the amount of precip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sternarchorhamphus
''Sternarchorhamphus'' is a monospecific genus of weakly electric belonging to the family Apteronotidae, the ghost knifefishes. The only species in the genus is ''Sternarchorhamphus muelleri''. This fish occurs in the Amazon and Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ... river basins in tropical South America. It has a long pointed snout and reaches up to about in total length. It is one of two species in the subfamily Sternarchorhamphinae. References Apteronotidae Fish of the Amazon basin Knifefish of Brazil Freshwater fish of Peru Freshwater fish of Venezuela Monotypic ray-finned fish genera Taxa named by Carl H. Eigenmann Taxa named by Franz Steindachner {{Gymnotiformes-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sternarchorhynchus
''Sternarchorhynchus'' is a genus of ghost knifefishes with a long, decurved snout that are found in river basins in tropical South America. Distribution, habitat and conservation Of the 32 recognized species, more than are restricted to the Amazon basin (including the Tocantins system) in Bolivia, Brazil, Colombia, Ecuador and Peru, 7 species are found in river basins flowing into the Gulf of Paria in Colombia and Venezuela (mostly Orinoco system, but ''S. mendesi'' in Guanipa and San Juan), ''S. freemani'' is from the Essequibo basin in Guyana, ''S. galibi'' is from the Maroni basin in French Guiana and Suriname, and ''S. britskii'' is from the upper Paraná basin in Brazil.de Santana, C. D. and R.P. Vari (2010). Electric fishes of the genus Sternarchorhynchus (Teleostei, Ostariophysi, Gymnotiformes); phylogenetic and revisionary studies. Zool. J. Linn. Soc. 159: 223-371. There are records of ''Sternarchorhynchus'' from the Oyapock on the French Guiana–Brazil border, bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
