Myliobatis ridens (lat.) Is a species of cartilaginous fish of the brackish genus of the bracken family of the order of the caudate-like over- order of the rays . These stingrays live in the subtropical waters of the southwest Atlantic . They are found at a depth of 47 m. The maximum recorded width of the disk is 70 cm. The pectoral fins of these slopes grow together with the head, forming a diamond-shaped disk whose width exceeds the length. The characteristic shape of the flat snout resembles a duck nose. Thin tail longer than disc. Coloring of the dorsal surface of an even dark brown or olive green color.
| Myliobatis ridens |
| Scientific classification |
|---|
| No rank : | Bilateral symmetrical |
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| International scientific name |
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Myliobatis ridens Ruocco, Lucifora, Díaz de Astarloa, Mabragaña & Delpiani, 2012 |
| Synonyms |
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Myliobatis sp. JMDAA-2012 |
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Like other caudate- shaped Myliobatis ridens reproduce by egg-production . Embryos develop in the womb, feeding on the yolk and histotroph [1] [2] .
Content
For the first time, a new species was scientifically described in 2012 [3] . Species epithet comes from the word lat. ridens - "smiling." The holotype is an adult male with a disc width of 53.1 cm, caught off the coast of Buenos Aires province . Paratypes: immature male with a disc 46.5 cm wide, immature females with a 29–49 cm wide disc, adult female with a 54.2–69 cm wide disc, adult males with a 49.1–57.4 cm wide disc same [4] .
Myliobatis ridens live in the southwestern Atlantic Ocean. They are kept in shallow water of the continental shelf at a depth of 5 to 47 m, but, as a rule, no deeper than 15 m [3] .
The pectoral fins of Myliobatis ridens , the base of which is located behind the eyes, fuse with the head, forming a diamond-shaped flat disk, whose width is approximately 2.2 times greater than the length, the edges of the fins have the shape of pointed “wings”. The head extends beyond the disc. The width of the rounded snout is equal to the distance between the eyes. Behind the medium-sized eyes, spread out on the sides of the head, are sprays . On the ventral surface of the disk there are 5 pairs of gill slits , mouth and nostrils. The width of the mouth is approximately equal to the distance between the fifth gill slits and exceeds the distance between the outer edges of the nostrils. Coloring of the dorsal surface of the disc even dark brown or olive green. The ventral surface of the disc is whitish with a dark orange or black edging of the pectoral fins. The base of the tail is lighter, and the tip becomes dark [3] . Between the nostrils lies a skin flap. The teeth form a flat rubbing surface. On the tail there is one or less often several poisonous thorns. [5] . The maximum recorded disk width is 70 cm [2] .
Like other caudate- shaped Myliobatis ridens belong to ovoviviparous fish. Embryos develop in the womb, feeding on the yolk and histotroph. Males and females reach puberty with a disk width of 50-60 cm.
Myliobatis ridens are not subject to commercial fishing. The International Union for Conservation of Nature has not yet evaluated the conservation status of the species.
- ↑ Animal life. Volume 4. Lancelet. Cyclostomes. Cartilaginous fish. Bone fish / ed. T. S. Rassa , ch. ed. V. E. Sokolov . - 2nd ed. - M .: Enlightenment, 1983. - S. 49. - 300,000 copies.
- ↑ 1 2 Myliobatis ridens in the FishBase database.
- ↑ 1 2 3 Ruocco, N. L; Lucifora, LO; Díaz de Astarloa, J. M; Mabragaña, E. & Delpiani, SM [ http://zoolstud.sinica.edu.tw/Journals/51.6/862.pdf Morphology and DNA Barcoding Reveal a New Species of Eagle Ray from the Southwestern Atlantic: Myliobatis ridens sp. nov. (Chondrichthyes: Myliobatiformes: Myliobatidae)] // Zoological Studies. - 2012. - Vol. 51, No. 6 . - P. 862-873.
- ↑ Myliobatis ridens (neopr.) . Shark References .
- ↑ Bigelow, HB and WC Schroeder. Sawfishes, guitarfishes, skates and rays = In J. Tee-Van et al. (eds.) Fishes of the western North Atlantic. Part two .. - New Haven, Sears Found. Mar. Res., Yale Univ., 1953. - P. 1-514.