Fluvitrygon
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Fluvitrygon oxyrhynchus at the Shedd Aquarium in Chicago |
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| Scientific name | ||||||||||||
| Fluvitrygon | ||||||||||||
| Last , Naylor & Manjaji-Matsumoto, 2016 |
Fluvitrygon is a genus from the family of sting rays (Dasyatidae) that wasonly introduced in mid-2016. The three species of the genus live in freshwater and brackish water from estuaries in Southeast Asia. The distribution area includes the catchment area of Chao Phraya and Mae Nam Tapi in Thailand, the Mekong in Thailand and Cambodia, the Malay Peninsula , Borneo and Sumatra .
features
Fluvitrygon species are small to medium-sized rays that reach a disc width of 28 to 60 cm. The body disc is oval or almost round, the outer ends of the pectoral fins broadly rounded. The pelvic fins are medium-sized and are almost completely covered by the body disc. The snout is pointed or blunt at a wide angle. The slightly protruding eyes are small. The mouth is narrow to medium-sized and surrounded by two to eight oral papillae. The whip-like tail is short or long. Its length can reach 1.3 to 3.8 times the diameter of the body disk. The tail base is narrow and oval or almost round in cross section. The tail has no dorsal or ventral skin folds. The stinger sits far in front on the tail. A central row of thorns on the tail is missing or not very pronounced. In most cases, the posterior tail area of adult specimens has some small denticles . In the middle shoulder area there are up to two pearl-like thorns, on the back a denticle band, the edges of which are clearly delimited or diffuse. The rest of the back is usually flaky. On the back, the Fluvitrygon species are monochrome or strongly patterned, the belly is white. The edges of the body disc can be darkened. The tail is monochrome or patterned.
species
Currently (November 2016) three species are placed in the genus Fluvitrygon :
- Fluvitrygon kittipongi (Vidthayanon & Roberts, 2006)
- Fluvitrygon oxyrhynchus (Sauvage, 1878)
- Fluvitrygon signifer (Compagno & Roberts, 1982)
Systematics
The genus Fluvitrygon was introduced in mid-2016 by the Australian marine biologist Peter R. Last, the US ichthyologist Gavin JP Naylor and another colleague. The three species of the genus previously belonged to Himantura . The generic name is made up of "fluvius", the Latin word for river and "trygon", a Greek name for rays and refers to the occurrence in fresh waters. Type species of the genus is Himantura signifer Compagno & Roberts, 1982. From Brevitrygon , marine sister genus , differs Fluvitrygon of especially regarding morphology of the tail.
Individual evidence
- ↑ a b c d Last, PR, Naylor, GJP & Manjaji-Matsumoto, BM (2016): A revised classification of the family Dasyatidae (Chondrichthyes: Myliobatiformes) based on new morphological and molecular insights. Zootaxa , 4139 (3): 345-368. doi: 10.11646 / zootaxa.4139.3.2 , page 360.
- ↑ a b Fluvitrygon signifer on Fishbase.org (English)
- ↑ Fluvitrygon kittipongi on Fishbase.org (English)