Sabretooth or sabertooth may refer to:
The payara, Hydrolycus scomberoides, is a species of dogtooth tetra. This predatory fish is found in the Amazon Basin in tropical South America. It was the first of four species to be described in the genus Hydrolycus.
The Orinoco crocodile is a critically endangered crocodile. Its population is very small, and they can only be found in the Orinoco river basin in Venezuela and Colombia. Extensively hunted for their skins in the 19th and 20th centuries, it is one of the most endangered species of crocodiles. It is a very large species of crocodilian; males have been reported up to 6.8 m in the past, weighing over 900 kg (2,000 lb), but such sizes do not exist today, 5.2 m being a more widely accepted maximum size. A large male today may attain 4.2 m in length and can weigh up to 450 kg (1,000 lb), while females are substantially smaller with the largest likely to weigh around 225 kg (496 lb). Sexual dimorphism is not as profound as in other crocodilian species. The coloration is light even in adults.
Cynodontidae, also known as dogtooth characins or vampire tetras, are a family of predatory, characiform freshwater fishes from South America. This group is not very diverse, and includes only five genera and 14 species. Most of what is known about this family is from the members of the subfamily Cynodontinae, which includes the largest species of this family, up to 117 cm (3.84 ft). The members of subfamily Roestinae only reach up to 20 cm (7.9 in). and are less known.
The ocellate river stingray, also known as the peacock-eye stingray or black river stingray, is a species of freshwater stingray in the family Potamotrygonidae. It was the first species to be described in the family and is also the most widespread, ranging throughout much of the Río de la Plata, Amazon, Mearim and Orinoco basins in tropical and subtropical South America. It is sometimes kept in aquaria.
The tambaqui is a large species of freshwater fish in the family Serrasalmidae. It is native to tropical South America, but kept in aquaculture and introduced elsewhere. It is also known by the names black pacu, black-finned pacu, giant pacu, cachama, gamitana, and sometimes as pacu.
Guianacara is a small genus of cichlid fish endemic to freshwater habitats in the Guiana Shield in South America. They mostly live in moderately flowing clear- or blackwater rivers and streams, but also occur in lagoons that are seasonally flooded. They are typically found over bottoms consisting of sandy patches intermixed with large rocks.
Salminus brasiliensis, also known as the golden dorado, dorado, river tiger, dourado, or jaw characin is a large, predatory characiform freshwater fish found in central and east-central South America. Despite having Salminus in its name, the dorado is not related to any species of salmon, nor to the saltwater fish also called dorado. It is very popular among recreational anglers and supports large commercial fisheries.
Cynodontinae is a subfamily of tropical and subtropical South American fishes of the family Cynodontidae. They are characterized by an oblique mouth and very long distinct canines, which are used to capture and stab their prey, other fish that can be up to half the length of the cynodontine itself. They are not prized as food fish, but are important in subsistence and commercial fisheries. Hydrolycus are game fish, having been recently added to the International Game Fish Association in the fly and rod class. Cynodontid fish are also sometimes housed in aquaria.
Piaractus brachypomus, the Red-Bellied Pacu or Pirapitinga, is a large species of pacu, a close relative of piranhas and silver dollars, in the serrasalmid family. It is native to the Amazon basin in tropical South America, but it formerly included populations in the Orinoco, which was described in 2019 as a separate species, P. orinoquensis. Additionally, P. brachypomus is widely farmed and has been introduced to other regions. In South Florida they are invasive in rivers, canals or lakes.
The biara is a South American piscivorous fish in the dogtooth characin family. It belongs to the monotypic genus Rhaphiodon, although some minor differences in morphometrics and colour are known from across its large range. It is found in the Amazon, Orinoco, and Río de la Plata Basins, as well as rivers of the Guianas. It occurs in a wide range of freshwater habitats such as main river channels, flooded forests, lakes and reservoirs. Some populations are migratory.
Cynodon is a genus of dogtooth characins from tropical South America, including the Amazon and Orinoco basins, and rivers in the Guianas. These predatory fish reach up to 32.2 cm (1.06 ft) in standard length. They are mainly piscivorous, but will also take insects.
Hydrolycus is a genus of large dogtooth characins from tropical South America, where found in the Amazon and Orinoco basins, as well as rivers of the Guianas. The genus includes the largest dogtooth characins, reaching up to 1.17 m (3.8 ft) in length. They have long, pointed teeth used for spearing their prey, generally smaller fish. In a study of the stomachs of 45 individuals, most were empty, but among the remaining the prey fish were 15–50% of the length Hydrolycus itself.
Steatogenys is a genus of gymnotiform knifefishes found in the Amazon, Orinoco and Essequibo river basins in tropical South America. The widespread and common S. elegans is found in a wide range of habitats, from the shallow essentially static waters such as floodplain lakes to fast-flowing rivers as deep as 50 m (160 ft). The two remaining species are less common and widespread, with A. duidae found mainly in small streams running through terra firme forests and S. ocellatus among submerged roots and branches in static or slow-flowing blackwater habitats. All three are regularly found among vegetation in floating meadows, a habitat that often contains little oxygen, but they are well-adapted to this.
Microphilypnus is a genus of small fishes in the family Eleotridae native to the Amazon and Orinoco basins in South America. At up to 2.4 cm (0.94 in) in standard length, they are among the smallest sleeper gobies, but however larger than the Leptophilypnion sleeper gobies from the same region. The bottom-dwelling Microphilypnus are typically found in shallow water among leaf-litter or partially buried in sand, and they can be very abundant in their habitat. Their small size combined with a speckled and semi-transparent appearance makes them highly cryptic. They somewhat resemble certain freshwater shrimp, as well as Priocharax characins, and they sometimes group together. Microphilypnus feed on tiny invertebrates.
Cynodon septenarius, the silver paraya, is one of three species of dogtooth characins in the genus Cynodon. It is the most recently described member of its genus. This fish is found in tropical fresh waters of South America, including the Amazon and Orinoco basins, and rivers in Guyana.
Mylossoma duriventre, the silver mylossoma, is a species of freshwater serrasalmid fish endemic to tropical and subtropical South America. It grows to a maximum length of about 25 cm (10 in) and a weight of 1 kg (2.2 lb). It is the subject of a local fishery, being known as 'pacu' in Brazil and 'palometa' in Venezuela.
A whitewater river is classified based on its chemistry, sediments and water colour. Whitewater rivers have high levels of suspended sediments, giving the water a pH that is near-neutral, a high electric conductivity and a pale muddy, café au lait-like colour. Whitewater rivers are of great ecological importance and are important to local fisheries. The major seasonal Amazonian floodplains known as várzea receive their water from them.
Hydrolycus tatauaia is a species of dogtooth characin found in the Amazon, Orinoco and Essequibo basins in tropical South America. Adults mainly occur in deep and/or fast-flowing rivers. It is migratory, moving upstream to breed in November–April.
Boulengerella cuiveri, commonly known as the bicuda, is a species of pike-characin in the family Ctenoluciidae.
