Hemitrygon akajei
| Hemitrygon akajei | ||||||||||||
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Hemitrygon akajei |
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| Scientific name | ||||||||||||
| Hemitrygon akajei | ||||||||||||
| ( Müller & Henle , 1841) |
Hemitrygon akajei is a species of ray and lives in the northwestern Pacific from Thailand to southern Japan . There are also reports of occurrences from Fiji and Tonga .
features
Hemitrygon akajei can reach a total length of 2 m and a width of 66 cm, but most adults are no longer than 1 m. It has a pentagonal pectoral fin disc that is slightly longer than it is wide. The front end of the disc is pointed and is formed by the triangular snout, the other corners are rounded. The eyes are in raised sockets, behind them are spray holes that are about twice as large. There is a thick flap of skin between the breathing holes. The teeth are grouped in a kind of quincunx pattern in the upper and lower jaw . Young animals and females have rounded teeth, adult males pointed. The tail is whip-like and 1 to 1.5 times as long as the disc. The back is reddish brown, which merges into orange towards the fin edge. The belly is orange-red. Like all stingrays, it has a poisonous sting.
Way of life
The species lives on the continental shelf in the northwestern Pacific, preferentially in shallow water over a sandy bottom, but also at greater depths. It feeds on smaller fish such as the Japanese sardine ( Sardinops sagax melanostictus ) and crustaceans such as the sand shrimp . Hemitrygon akajei is ovoviviparous with litters of up to ten pups.
Systematics
The ray species was described in 1841 by the German scientists Johannes Müller and Jakob Henle under the scientific name Trygon akajei , later assigned to the genus Dasyatis . When the Dasyatidae was revised in mid-2016 , the species was placed in the genus Hemitrygon .
literature
- PR Last and LJV Compagno: Dasyatidae . Stingrays. In: Kent E. Carpenter, Volker H. Niem (Eds.): The living marine resources of the Western Central Pacific . tape 3 , Batoid fishes, chimaeras and Bony fishes part 1 (Elopidae to Linophrynidae). Food and agricultural organization of the United Nations, 2001, ISSN 1020-6868 , p. 1479–1505 (English, 203.158.191.28 [PDF]).
Individual evidence
- ↑ 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
Web links
- Hemitrygon akajei on Fishbase.org (English)
- Hemitrygon akajei on the IUCN Red List