| Tatiana's river stingray | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Order: | Myliobatiformes |
| Family: | Potamotrygonidae |
| Genus: | Potamotrygon |
| Species: | P. tatianae |
| Binomial name | |
| Potamotrygon tatianae Silva & Carvalho, 2011 | |
Potamotrygon tatianae, the Tatiana's river stingray, is a species of river stingray (Potamotrygonidae) endemic to the Madre de Dios River and upper Madeira River basins in Peru.
This river stingray's oval disc is longer than wide (disc length between 102 and 131% of the disc width). The total length of the species is up to 75.5 cm (2 ft 5.7 in), the disc length up to 47.5 cm (1 ft 6.7 in) and the disc width up to 36.2 cm (1 ft 2.3 in). The mouth is small, opening relatively straight across, and has two lateral and three central papillae. One of the central papillae is closer to the lower jaw tooth plate. The teeth are relatively small, with 36-46 rows in the upper jaw and 33‑45 in the lower jaw.
The background colour is generally blackish-brown with beige, light beige, or dark brown spots.
This species was named after Tatiana Raso de Moraes Possato, a late student of biology who was an enthusiastic researcher of chondrichthyans, in particular potamotrygonids.
The types are housed in Brazil at the Museum of Zoology of the University of São Paulo: MZUSP 107673; Paratype: MZUSP 107667; MZUSP 107668).
River stingrays or freshwater stingrays are Neotropical freshwater fishes of the family Potamotrygonidae in the order Myliobatiformes, one of the four orders of batoids, cartilaginous fishes related to sharks. They are found in rivers in tropical and subtropical South America. A single marine genus, Styracura, of the tropical West Atlantic and East Pacific are also part of Potamotrygonidae. They are generally brownish, greyish or black, often with a mottled, speckled or spotted pattern, have disc widths ranging from 31 to 200 centimetres (1.0–6.6 ft) and venomous tail stingers. River stingrays feed on a wide range of smaller animals and the females give birth to live young. There are more than 35 species in five genera.
The roughback whipray is a rare species of freshwater stingray in the family Dasyatidae, found over sandy bottoms in the Mae Klong and Chao Phraya Rivers of Thailand. Growing no more than 29 cm (11 in) across, this small ray has an oval pectoral fin disc and a whip-like tail without fin folds. It closely resembles the white-edge freshwater whipray in appearance, but can be distinguished by its coloration: light gray to dark orange-brown above and white below with a dark band along the lateral margins. Another identifying feature is a "pearl organ" at the center of the back, found in individuals of all ages. All of the original specimens of the roughback whipray were found with extensive wounds to the fins and tail. The International Union for Conservation of Nature (IUCN) has assessed this species as Endangered, citing the extensive habitat degradation and heavy fishing pressure within its limited range.
Plesiotrygon, the antenna rays, is a small genus of freshwater stingrays in the family Potamotrygonidae endemic to the Amazon basin in South America. They are found in large rivers and the lower part of their tributaries. The maximum disc width is up to 58 cm (23 in), but both species are very long-tailed.
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.
Potamotrygon is a genus of freshwater stingrays in the family Potamotrygonidae native to the rivers of South America, and sometimes seen in the aquarium trade.
The Niger stingray or smooth freshwater stingray, Dasyatis garouaensis, is a species of stingray in the family Dasyatidae, native to rivers in Nigeria and Cameroon. Attaining a width of 40 cm (16 in), this species can be distinguished by its thin, almost circular pectoral fin disk, slightly projecting snout tip, and mostly smooth skin with small or absent dermal denticles. The Niger stingray feeds on aquatic insect larvae and is ovoviviparous. The long stinging spine on the tail of this ray can inflict a painful wound. It has been assessed as Vulnerable by the International Union for Conservation of Nature (IUCN), as its numbers are declining in some areas and it faces heavy fishing pressure and habitat degradation.
The chupare stingray or Caribbean whiptail stingray, Styracura schmardae, is a species of stingray in the family Potamotrygonidae, found in the western Atlantic Ocean from the Gulf of Campeche to Brazil, including the Antilles. The presence of this species in the Gulf of Mexico has not been confirmed. It also occurs in the Bahamas. It usually inhabits sandy substrates, sometimes near coral reefs, and is an infrequent visitor to the Amazon River estuary. Leonard Compagno doubted the taxonomic validity of this species in his 1999 Checklist of Living Elasmobranchs.
The bigtooth river stingray or Tocantins River ray is a species of freshwater fish in the family Potamotrygonidae. It is endemic to the lower Tocantins basin and Araguaia basin in Brazil, and prefers muddy bottoms. It is sometimes kept in aquaria. This stingray is generally common and its population increased after the Tucuruí Dam was completed, unlike many other species in its range.
The Xingu River ray, white-blotched river stingray, or polka-dot stingray is a species of freshwater fish in the family Potamotrygonidae. It is endemic to the Xingu River basin in Brazil and prefers rocky bottoms. It is sometimes kept in aquaria. The Xingu river ray is a venomous stingray that contains venom localized at its dentine spine in its tail. While the ray's venom composition does not change with maturation, the venom toxicity decreases as rays get older. On the other hand, rays’ jaw shape, stiffness, and mineralization are strengthened with age, which allows mature rays the ability to consume hard-shelled invertebrates. These changes in traits with maturation reflect the different pressures rays experience in terms of functions such as feeding and avoiding predation during different maturity stages.
The raspy river stingray, mosaic stingray or arraia is a species of freshwater fish in the family Potamotrygonidae. This stingray is endemic to the Amazon basin in Brazil, where known from the Amazon–Pará River, the Madeira River basin, Uatumã River and lower Tocantins River.
The porcupine river stingray is a species of river stingray in the family Potamotrygonidae, the type of the Potamotrygon genus. It is found in the basins of the Paraná and Paraguay River basins in South America. Most chemical weathering of minerals seems to take place in the upland drainage basins rather than on the floodplains, and most major solutes display conservative mixing in the river-floodplain system. The population in the Rio Negro basin was described as a separated species, P. wallacei, in 2016.
The freshwater whipray is a little-known species of stingray in the family Dasyatidae, found in a number of large rivers and associated estuaries in northern Australia. Until recently, this species was regarded as a regional subpopulation of the similar-looking but much larger giant freshwater stingray of Southeast Asia. Typically reaching 1 m (3.3 ft) across, the freshwater whipray has a distinctively shaped, rounded pectoral fin disc, a projecting snout, and a thin tail without fin folds. It is plain brown above and white below with dark marginal bands. Can occasionally go on land and can "breathe" out of water for up to 7 minutes. The freshwater whipray is an active hunter of small fishes and shrimps, and does not currently face substantial conservation threats.
The roughnose stingray is a little-known species of stingray in the family Dasyatidae, generally found in shallow, estuarine waters associated with mangroves off Borneo, Sumatra, and possibly Java. Growing to 72 cm (28 in) across, this species has a rhomboid pectoral fin disc and a whip-like tail with a ventral fin fold. It is characterized by its pointed snout, which is covered by dermal denticles. Reproduction is aplacental viviparous, with females possibly bearing as few as one pup at a time. The International Union for Conservation of Nature (IUCN) has assessed the roughnose stingray as Endangered; it is threatened by overfishing and the destruction and degradation of its mangrove habitat.
The short-tailed river stingray is a species of river stingray native to the Río de la Plata Basin in South America. It is sometimes known as the giant freshwater stingray, but this name is typically used for the southeast Asian Himantura polylepis.
Heliotrygon gomesi, the Gomes's round ray or China ray, is a species of freshwater stingray native to the western Amazon basin in South America. It is the type species of its genus. It spends the day in deep river channels, but moves closer to the shore at night to feed.
Potamotrygon falkneri, the largespot river stingray or reticulated freshwater stingray, is a species of freshwater stingray in the family Potamotrygonidae from tropical and subtropical South America. It is sometimes seen in the aquarium trade, but requires a very large tank.
Potamotrygon tigrina, also known as the tiger river stingray, is a species of freshwater ray in the family Potamotrygonidae. This endangered species is endemic to black- and whitewater rivers in the upper Amazon basin in northeastern Peru. It is sometimes kept in aquariums and has been bred in captivity, but it is generally a sensitive species.
Potamotrygon magdalenae, the Magdalena River stingray, is a species of freshwater fish in the family Potamotrygonidae. It is found only in the Magdalena and Atrato basins in Colombia, but it is locally abundant and among the predominant fish species in its range. It is a small species of stingray with a typical disc width of about 20 cm (8 in), although it can reach up to 35 cm (14 in).
The black-tailed antenna ray or dwarf antenna ray is a species of freshwater stingray in the family Potamotrygonidae. It is native to the western Amazon basin in northeastern Peru, western Brazil and possibly eastern Ecuador. It is found both in the mainstream of the Amazon River and in smaller tributaries such as the Itaya and Pachitea Rivers. It is occasionally kept in aquariums and has been bred in captivity, but it is sensitive and the tail is easily damaged.
Potamotrygon rex, the great river stingray, is a species of freshwater stingray belonging to the family Potamotrygonidae, native to South America in the Neotropical region. P. rex, along with some other Potamotrygon species form a sub-species group known as "black stingrays" known by their similar features and their locality to rivers draining the Central Brazilian Shield. Specifically, it is native to the Rio Tocantins in the central Brazilian state of Tocantins. It is quite a large organism, weighing up to 20 kg. Its appearance is dark brown to blackish with distinct clusters of yellow-orange spots around similarly colored ocelli on its dorsal side. Distinguishing features include broad pelvic-fin apices, lack of labial grooves, irregular double row of dorsal tail thorns, and having two angular cartilages associated with each hyomandibula.