Dipturus grahami (lat.) - a species of cartilaginous fish of the rhombic family of rays of the order of stingrays. They live in the tropical waters of the southwestern and central western parts of the Pacific Ocean . They are found at a depth of up to 515 m. Their large, flattened pectoral fins form a rhombic disk with an elongated and pointed snout. The maximum recorded length is 64.1 cm. Eggs are laid [1] [2] [3] .
| Dipturus grahami |
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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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Dipturus grahami Last , 2008 |
| Security status |
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Least ConcernedIUCN 3.1 Least Concern : 195448 |
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Content
The species was first scientifically described in 2008 [4] . The holotype is a mature male 61.9 cm long, caught off the coast of New South Wales ( ) at a depth of 446-515 m. Paratypes: females 31.3–64.1 cm long and young males 38.4–46.8 cm long, caught there at a depth of 230–515 m; females 12–18 cm long and 55.5 cm long male, caught in the waters of Queensland at a depth of 410–457 m; [5] . The species is named after two unrelated Australian ichthyologists - Alistair Graham and Ken Graham [2] .
These bentopelagic rays are endemic to the waters of Australia (New South Wales, Queensland). They are found on the outer edge of the continental shelf and in the upper part of the continental slope at a depth of 70 to 515 m [5] . The most numerous in the range of 200-400 m. They prefer soft soil [3] .
The wide and flat pectoral fins of these rays form a rhombic disk with a rounded snout and rounded edges. On the ventral side of the disc are 5 gill slits, nostrils and mouth. On the long tail there are lateral folds. These skates have 2 reduced dorsal fins and a reduced caudal fin [1] .
The width of the disk is 1.3-1.4 times the length and equal to 76-83% of the length of the body. The elongated and pointed snout forms an angle of 84–96 °. The length of the short tail is 0.7-0.8 of the distance from the tip of the snout to the cloaca. The tail is thin. Its width in the middle part is 1.7–2.1 of its height and 1.4–2.0 at the base of the first dorsal fin. The distance from the tip of the snout to the upper jaw is 15-18% of the body length and 1.7-1.9 times the distance between the nostrils. The length of the head along the ventral side is 31–33% of the body length. The length of the snout is 2.9–3.5 times greater, and the diameter of the eye is 59–83% of the interorbital space. The height of the first dorsal fin is 1.5-2.1 times the length of its base. The distance between the beginning of the base of the first dorsal fin and the tip of the tail exceeds 2.7–3.0 times the length of its base and 3.6–5.4 times the length of the caudal fin. The length of the hind lobe in adult males reaches 17–18% of the body length, and the length of the anterior lobe is 66–69% of the length of the hind. The length of the pterigopodia is 27–28% of the body length. The front edge of both surfaces of the disk is covered with narrow strips of spines. In the occipital region there is 1 spike; in adults, spines in the malar region are absent; in males, the tail carries 1 row of spines. Females have additional lateral rows of spines. The pectoral fins are formed by 80–85 rays. The number of vertebrae is 118-127. There are 34–37 dentitions on the upper jaw. The dorsal surface of the disc is an even dark brown color. The ventral surface is slightly lighter, gray-cinnamon. Sensitive pores located on the ventral side of the disc, with a weak dark rim, but without gray circles [4] . The maximum recorded length is 64.1 cm [4] .
Like other rhombic, these stingrays lay eggs enclosed in a rigid horn capsule with protrusions at the ends. Embryos feed exclusively on yolk . The length of adult males is 54.5–62.2 cm. The smallest free-swimming individual had a length of 18.3 cm [2] .
Not subject to target fishing. May be caught as by- catch . The area is subject to seasonal minor fishing. The International Union for Conservation of Nature has rated conservation status as “Least Concerned” [3] .
- ↑ 1 2 Froese, Rainer, and Daniel Pauly, eds. Family Rajidae - Skates (Neopr.) . FishBase
- ↑ 1 2 3 Dipturus grahami in the FishBase database.
- ↑ 1 2 3 Dipturus grahami . The IUCN Red List of Threatened Species .
- ↑ 1 2 3 Last P. New short-snout members of the skate genus Dipturus ( Rajoidei: Rajidae ) from Australian seas // CSIRO Marine and Atmospheric Research Paper. - 2008 .-- Vol. 21. - P. 53-98.
- ↑ 1 2 Dipturus grahami (neopr.) . Shark-References. Date of treatment May 26, 2016.
