Maskray

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Maskrays
Blue-spotted Stingray (Neotrygon kuhlii) (8465011759).jpg
Neotrygon orientale
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Myliobatiformes
Family: Dasyatidae
Genus: Neotrygon
Type species
Raya trigonoides (New Caledonian maskray)
Castelnau, 1873

Neotrygon is a genus of stingrays in the family Dasyatidae commonly known as the Maskrays, native to the Indo-West Pacific. They are so named because of a distinctive color pattern around their eyes, resembling a mask. The species in this genus were originally placed in the genus Dasyatis by most authors. However, recent morphological and molecular analyses have conclusively showed that they represent a distinct group and so the genus Neotrygon was resurrected for them.[2]

Aside from their mask-like color pattern, the maskrays are variable in coloration and can be plain or ornate. Their pectoral fin discs are largely smooth, with a single row of thorns along the dorsal midline. The mouth is small with two central papillae and a row of enlarged, long-cusped teeth halfway along the upper jaw on both sides. The nasal curtain, formed by the merging of the nasal flaps, is long and narrow. The tail is very short with well-developed dorsal and ventral fin folds and a filamentous tip, and is banded black and white past the stinging spine. In addition, Neotrygon species also differ from other stingrays in their buccal and skeletal morphology,[2][3] as well as in the CO1 and ND2 gene sequences.[4][5]

Within the genus Neotrygon, species can be diagnosed by their nucleotide sequence at the CO1, ND2, and cytochrome b genes.[5][6][7][8] Alternative diagnoses have been proposed based on morphometrics [3] but these were shown to be invalid.[7][9]

Species[edit]

There are currently 16 recognized species in the genus Neotrygon:

Neotrygon trigonoides, the type species of the genus Neotrygon, occurs on the reefs and reef-associated habitats of the Coral Sea. The holotype was collected by Castelnau in New Caledonia, hence its vernacular designation as the New Caledonian maskray.[10] Neotrygon kuhlii (Kuhl's maskray) is known from only two specimens collected by French naturalists J.R.C. Quoy and J.P. Gaymard in Vanikoro (Santa Cruz archipelago, southwestern Pacific Ocean) in 1828, and by the watercolour of another specimen drawn by Quoy.[12] As Kuhl's maskray superficially resembles the New Caledonian maskray, it cannot be excluded that the two species are synonymous.[12] To test this hypothesis would require the comparison of maskray specimens from Vanikoro and the Coral Sea using genetic markers. Neotrygon indica apparently has a wide distribution in the Indian Ocean, while several other species have so far been recorded from single locations: the latter category includes Neotrygon kuhlii, so far known from Vanikoro Island only; Neotrygon westpapuensis from Biak Island in West Papua; and Neotrygon vali from Guadalcanal Island in he Solomon archipelago.[9] Neotrygon bobwardi is distributed all along the western coast of Sumatera Island in Indonesia, from Padang to Aceh; Neotrygon malaccensis occurs in the eastern Andaman Sea and in the Malacca Strait; Neotrygon varidens occurs in the South China Sea. Neotrygon orientale has a wide distribution spanning the western Indo-Malay archipelago and the Philippines archipelago; Neotrygon moluccensis has so far been reported from the eastern Banda Sea; Neotrygon caeruleopunctata occurs along the Indian-Ocean shores of Bali and Java Islands; Neotrygon australiae is present all along the northern coast of Australia and around Timor Island.[7]

References[edit]

  1. ^ a b Castelnau, F. de (1873). "Contribution to the ichthyology of Australia". Proc. Zool. Acclim. Soc. Victoria. 2: 37–358.
  2. ^ a b Last, P.R. & White, W.T. (2008). "Resurrection of the genus Neotrygon Castelnau (Myliobatoidei: Dasyatidae) with the description of Neotrygon picta sp. nov., a new species from northern Australia. In: Last, P.R., White, W.T. & Pogonoski, J.J (Eds.), Descriptions of New Australian Chondrichthyans" (PDF). CSIRO Marine and Atmospheric Research. Paper 022: 315–325.
  3. ^ a b c d e Last, P.R., White, W.T. & Séret, B. (2016): Taxonomic status of maskrays of the Neotrygon kuhlii species complex (Myliobatoidei: Dasyatidae) with the description of three new species from the Indo-West Pacific. Zootaxa, 4083 (4): 533–561.
  4. ^ Ward R D, Holmes B H, White W T, Last P R (2008): DNA barcoding Australasian chondrichthyans: results and potential uses in conservation. Marine and Freshwater Research, 59: 57-71.
  5. ^ a b Naylor G J P, Caira J N, Jensen K, Rosana K A M, White W T, Last P R (2012): A DNA sequence-based approach to the identification of shark and ray species and its implications for global elasmobranch diversity and parasitology. Bulletin of the American Museum of Natural History, 367: 1-262.
  6. ^ Borsa, P.; Shen, K.-N.; Arlyza, I.S. & Hoareau, T.B. (2016), "Multiple cryptic species in the blue-spotted maskray (Myliobatoidei: Dasyatidae: Neotrygon spp.): An update.", Comptes Rendus Biologies, 339: 417–426[1]
  7. ^ a b c d e f g Borsa, P., Arlyza, I.S., Hoareau, T.B. & Shen, K.-N. (2018): Diagnostic description and geographic distribution of four new cryptic species of the blue-spotted maskray species complex (Myliobatoidei: Dasyatidae; Neotrygon spp.) based on DNA sequences. Chinese Journal of Oceanology and Limnology, doi:10.1007/s00343-018-7056-2.
  8. ^ a b Pavan-Kumar, A.; Kumar, R.; Pitale, P.; Shen, K.-N.; Borsa, P. (2018). "Neotrygon indica sp. nov., the Indian-Ocean blue-spotted maskray (Myliobatoidei, Dasyatidae)". Comptes Rendus Biologies. 341: 120–130. doi:10.1016/j.crvi.2018.01.004.
  9. ^ a b c Borsa, P. (2017), "Neotrygon vali, a new species of the blue spotted maskray complex (Myliobatoidei: Dasyatidae)", Species, 18 (60): 146–153[2]
  10. ^ a b Borsa, P., Arlyza, I.S., Chen, W.-J., Durand, J.-D., Meekan, M.G. & Shen, K.-N. (2013): Resurrection of New Caledonian maskray Neotrygon trigonoides (Myliobatoidei : Dasyatidae) from synonymy with N. kuhlii, based on cytochrome-oxidase I gene sequences and spotting patterns. Comptes Rendus Biologies, 336 (4): 221-232.[3]
  11. ^ Garman, S (1885): Notes and descriptions taken from selachians in the U.S. National Museum. Proceedings of the United States National Museum, 8: 39-44.
  12. ^ a b Borsa, P. & Beraez, P. (2016), "Notes on the origin of Müller and Henle's illustration and type material of the blue-spotted maskray Neotrygon kuhlii (Myliobatoidei: Dasyatidae).", Cybium, 40: 255–258[4]