Dasyatis izuensis (lat.) Is a species of the genus of stingrays from the family of the caudate - tailed squad of the caudate-like superorder of rays . They live in the subtropical waters of the northwestern Pacific . They are found at a depth of 10 m. The maximum recorded width of the disk is 42 cm. The pectoral fins of these slopes fuse with the head, forming a diamond-shaped disk, the width of which is equal to the length. The snout is blunt. The tail is relatively short. Behind the thorn on the caudal stem are ventral and dorsal keels. The ventral fin fold is white. The dorsal surface of the disc is golden brown. Like other caudate-like Dasyatis izuensis reproduce by egg-production . Embryos develop in the womb, feeding on the yolk and histotroph . Not subject to target fishing. To date, no more than 10 individuals have been captured [1] [2] .
| Dasyatis izuensis |
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| Scientific classification |
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| No rank : | Bilateral symmetrical |
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| International scientific name |
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Dasyatis izuensis K. Nishida & Nakaya , 1988 |
| Security status |
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Close to vulnerableIUCN 3.1 Near Threatened : 60155 |
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Dasyatis izuensis was first scientifically described in 1988 [3] . The holotype is an adult male with a 41.8 cm wide disc caught by a gill net in the waters of Shizuoka Prefecture at a depth of 10 m ( ). Paratypes: immature males with a disc 18.2-19.7 cm wide, a young male with a 36.2 cm wide disc, immature females with a 18.2-22.8 cm wide disc, an adult female with a 36.7 cm wide disc and adult male with a disk 37.5 cm wide, caught there [4] . The species is named for its geographical habitat ( Izu Peninsula ).
Dasyatis izuensis live in the northwestern Pacific Ocean off the coast of the Izu Peninsula, located on the east coast of Honshu Island. These bottom stingrays are found in coastal waters at a depth of 10 to 20 m [2] .
The pectoral fins of these slopes fuse with the head, forming a diamond-shaped flat disk, the width of which slightly exceeds the length. The front edge of the disc is slightly curved. The snout is blunt. Behind the medium-sized eyes are large spatter . On the ventral surface of the disc are 5 gill slits, mouth and nostrils. Between the nostrils lies a flap of skin with a fringed lower edge. The mouth is curved in the form of an arc, at the bottom of the oral cavity there are 5 processes, of which two extreme ones are thinner than the others. The teeth are staggered and form a flat surface. Unlike females and immature individuals, the teeth of males are pointed. In the mouth there are 35β41 upper and 37β39 lower dentitions. The wide ventral fins are triangular in shape. The tail in the form of a whip is equal in length to the disk. Like other stingrays, on the dorsal surface in the central part of the caudal stem there is a serrated spike connected by ducts to the poisonous gland. Sometimes stingrays have 2 spikes. Periodically, the spike breaks off and a new one grows in their place. On average, the length of the spike in males is 6.8 cm, and in females 7.9 cm. The number of notches is 112 and 130, respectively [5] . Behind the thorn on the caudal peduncle are the ventral and dorsal skin folds. [3] [6]
The skin of most individuals is smooth, with large slopes in the area in front of the spike there are 2-6 bone plaques. The dorsal surface of the disc is golden brown; the area between the eyes and one third of the tail are black. The ventral surface of the disc is white, darkens towards the edges. Ventral fin skin fold of white color. The maximum recorded disk width is 42 cm [3] .
Like other caudate-shaped Dasyatis izuensis belongs to ovoviviparous fish. Embryos develop in the womb, feeding on the yolk and histotroph. Puberty occurs at a disc width of 37 cm [2] .
Dasyatis izuensis are not targeted. Caught in by-catch in commercial fishing using gillnets. The International Union for Conservation of Nature has assigned this species a conservation status of βClose to Vulnerabilityβ [2] .
