| Bennett's stingray | |
|---|---|
 | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Order: | Myliobatiformes |
| Family: | Dasyatidae |
| Genus: | Hemitrygon |
| Species: | H. bennetti |
| Binomial name | |
| Hemitrygon bennetti | |
| Synonyms | |
TheBennett's stingray orfrilltailed stingray (Hemitrygon bennetti, often misspelledbenetti orbennettii)[2] is a little-knownspecies ofstingray in thefamilyDasyatidae, with a wide but ill-defined distribution in theIndian andPacific Oceans. This species is characterized by a rhomboid, yellow-brownpectoral fin disc with a fairly long snout, and an extremely long tail with a correspondingly long ventral fin fold. It measures up to 50 cm (20 in) across. It feeds on fish, and isaplacental viviparous. It is likely caught bydemersalfisheries.
The fish is possibly named in honor of zoologistEdward Turner Bennett (1797-1836),[3]
German biologistsJohannes Peter Müller andFriedrich Gustav Jakob Henle described the Bennett's stingray asTrygon bennettii in their 1839–1841Systematische Beschreibung der Plagiostomen. They referenced three specimens as the speciessyntypes: only the one fromChina remains, while another fromTrinidad and a third of unknown provenance have been lost. Later authorssynonymized the genusTrygon withDasyatis.
The range of the Bennett's stingray is somewhat uncertain due to confusion with other species. It is abottom-dweller that occurs in the coastal waters of theIndo-Pacific region, fromIndia, throughIndochina, to southernChina,Japan, and perhaps thePhilippines; it seems to be most common in the northwestern Pacific. This species has also been reported fromVanuatu andNew Caledonia; the single historical record from Trinidad may be a misidentification.[1][2] It has been known to enterfresh water, including thePerak River inpeninsular Malaysia and theIndragiri River inSumatra.[4]
The Bennett's stingray has a diamond-shapedpectoral fin disc almost as wide as long, with straight leading margins converging on a triangular, moderately protruding snout. The trailing margins of the disc are convex. There are 31 upper and 33 lower tooth rows, and 3 or 5 papillae across the floor of the mouth. The tail is whip-like and can measure three times the length of the disc, proportionately longer than any other North PacificDasyatis species.[5] There is a stinging spine on the upper surface of the tail, and a fin fold underneath measuring 60–67% the disc width. Young individuals have smalldermal denticles in the middle of the back, whereas adults have a row of tubercles along the midline of the back and tiny thorns covering the tail. The coloration is yellowish brown above, becoming darker on the tail fold, and light below.[5] This species attains a disc width of 50 cm (20 in) and a total length of 1.3 m (4.3 ft).[1]
There is little information on the natural history of the Bennett's stingray.[1] It preys onfish, and isaplacental viviparous like other stingrays.[2]
The Bennett's stingray is susceptible tobottom trawl andnet gear and probably caught byfisheries within its range, which include intensive, targeted ray fisheries offThailand,Singapore,India, and elsewhere. TheInternational Union for Conservation of Nature (IUCN) has listed this species as vulnerable.[1]
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