Porcupine ray



Porcupine ray
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Myliobatiformes
Family: Dasyatidae
Genus: Urogymnus
Species: U. asperrimus
Binomial name
Urogymnus asperrimus
(Bloch & Schneider, 1801)
Range of the porcupine ray
Synonyms

Raja africana Bloch & Schneider, 1801
Raja asperrima Bloch & Schneider, 1801
Urogymnus asperrimus solanderi Whitley, 1939
Urogymnus rhombeus Klunzinger, 1871

The porcupine ray, Urogymnus asperrimus, is a species of stingray in the family Dasyatidae, found in shallow coastal waters throughout the tropical Indo-Pacific and off West Africa. Growing over 1 m (3.3 ft) across, the porcupine ray has a thick, rounded pectoral fin disk uniformly gray above and white below, and small eyes. Unlike other stingrays, it does not have a venomous spine on its tail. Its common name comes from the numerous large thorns covering the back and tail of adults.

Little is known of the biology of the porcupine ray; it feeds on benthic invertebrates and is likely aplacental viviparous as in other members of its family. Historically, this species was valued as a source of shagreen; its tough, spiny skin was used to cover shields, hilts, and other items. In addition, its tail was used as a rasping tool. The porcupine ray is declining in numbers throughout its range from human exploitation and habitat degradation, and has been assessed as Vulnerable by the International Union for Conservation of Nature (IUCN).

Contents

Taxonomy

Early illustration of a porcupine ray, from Fauna of British India (1889).

The porcupine ray was originally described as Raja asperrima by German naturalists Marcus Elieser Bloch and Johann Gottlob Schneider, in Systema Ichthyologiae (1801), based on a partial dried skin from Mumbai, India. In the same work they also described a West African form, Raja africana, which is now regarded to be the same species (being described in the same work, some confusion has existed over which name has priority, meaning that the species name africanus – rather than asperrimus – can be seen in several recent works when referring to the porcupine ray).[2]

In 1837, Johannes Peter Müller and Friedrich Gustav Jakob Henle moved the porcupine ray into its own genus, Urogymnus.[2] The specific epithet asperrimus is Latin for "roughest".[3] Other common names include black spotted ray, rough-skinned ray, roughback stingaree, solanders ray, and thorny ray.[4]

Distribution and habitat

The porcupine ray is widely distributed in the Indian and Pacific Oceans, from South Africa and Madagascar to the Arabian Peninsula and the Indian subcontinent, to Southeast Asia, the Philippines, and Indonesia, to as far east as New Guinea, Australia, and Fiji. It is also present off the coasts of Senegal, Guinea, and Côte d'Ivoire, and has colonized the eastern Mediterranean Sea through the Suez Canal.[5] This species is typically encountered on sandy flats or coral rubble near reefs, or inside caves. It also ventures into brackish environments.[4][6]

Description

The porcupine ray is rounded and covered by sharp thorns.

Large and heavy-bodied, the porcupine ray grows to 2.2 m (7.2 ft) long and over 1 m (3.3 ft) across. Its pectoral fin disk is rounded and very thick, slightly longer than wide, with a blunt-tipped snout. The eyes are tiny and smaller than the spiracles. The mouth is small, containing around 48 tooth rows in either jaw, and 3–5 papillae on the floor.[6][7] The tail is thin and no longer than the disk, with no fin fold or stinging spine.[8] The dorsal surface of adults is covered with heart-shaped tubercles interspersed with large, sharp thorns, with dense patches of smaller, flattened denticles on the center of the disk and the tail. This species is light gray above and white below, darkening towards the tip of the tail.[6]

Biology and ecology

Porcupine rays are relatively uncommon compared to other stingray species that share its range.[5] They feed primarily on sipunculids, polychaete worms, and crustaceans.[8] Known parasites of this species include the tapeworm Rhinebothrium devaneyi, the nematode Echinocephalus overstreeti, and the monogeneans Dendromonocotyle urogymni and Neoentobdella baggioi.[9][10][11] Virtually nothing is known of the porcupine ray's life history; it is presumably aplacental viviparous like other stingrays, with the developing embryos being sustained on yolk and later histotroph ("uterine milk") secreted by the mother.[4]

Human interactions

Despite not having a stinging spine, the porcupine ray is capable of injuring humans with its many sharp thorns.[4] It is reportedly bold and tolerant of divers approaching closely.[12] This species is believed to be of limited commercial importance on virtue of being difficult to handle; the meat, skin, and cartilage are of value.[4] The skin in particular is prized for making shagreen, a type of leather. Historically, it was often used to cover shields and the hilts of various weapons, as its extremely rough texture prevented slippage during battle. In Japan, the porcupine ray was the only species whose skin was deemed acceptable for covering sword hilts.[13][14] The Chinese also utilized porcupine ray shagreen ornamentally, by grinding down the thorns to yield a mottled pattern.[15] The native inhabitants of Funafuti Atoll used dried portions of the porcupine ray's tail as a rasp-like tool.[16]

In modern times, porcupine rays are mostly taken as bycatch in demersal tangle net operations.[4] These fisheries are largely unregulated and have resulted in this species declining or vanishing from the Bay of Bengal, the Gulf of Thailand, and likely elsewhere in its range. Additional threats to porcupine ray populations include habitat degradation from coastal development, and depletion of its food supply from overfishing. The International Union for Conservation of Nature (IUCN) has assessed this species as Vulnerable; it is not the target of any conservation measures.[5]

References

  1. ^ Compagno, L.J.V. (2000). Urogymnus asperrimus. In: IUCN 2000. IUCN Red List of Threatened Species. Downloaded on Jun. 3, 2009.
  2. ^ a b Catalog of Fishes. California Academy of Sciences Ichthyology. Retrieved on June 4, 2009.
  3. ^ Harkness, A. (1898). A Complete Latin Grammar. American Book Company. p. 57. 
  4. ^ a b c d e f Froese, Rainer, and Daniel Pauly, eds. (2009). "Urogymnus asperrimus" in FishBase. June 2009 version.
  5. ^ a b c Fowler, S.L., Cavanagh, R.D., Camhi, M., Burgess, G.H., Cailliet, G.M., Fordham, S.V., Simpfendorfer, C.A. and Musick, J.A. (2005). Sharks, Rays and Chimaeras: The Status of the Chondrichthyan Fishes. International Union for Conservation of Nature and Natural Resources. pp. 352–353. ISBN 2831707005. 
  6. ^ a b c Last, P.R. and Compagno, L.J.V. (1999). "Myliobatiformes: Dasyatidae". in Carpenter, K.E. and Niem, V.H.. FAO identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Rome: Food and Agricultural Organization. p. 1497. ISBN 9251043027. 
  7. ^ Smith, J.L.B., Smith, M.M. and Heemstra, P. (2003). Smiths' Sea fishes. Struik. p. 141. ISBN 1868728900. 
  8. ^ a b Randall, J.E. and Hoover, J.P. (1995). Coastal fishes of Oman. University of Hawaii Press. p. 47. ISBN 0824818083. 
  9. ^ Brooks, D.R. and Deardorff, T.L. (Jun. 1988)). "Rhinebothrium devaneyi n. sp. (Eucestoda: Tetraphyllidea) and Echinocephalus overstreeti Deardorff and Ko, 1983 (Nematoda: Gnathostomatidae) in a Thorny Back Ray, Urogymnus asperrimus, from Enewetak Atoll, with Phylogenetic Analysis of Both Species Groups". The Journal of Parasitology 74 (3): 459–465. 
  10. ^ Chisholm, L. and Whittington, I. (Jun. 2009). "Dendromonocotyle urogymni sp. nov. (Monogenea, Monocotylidae) from Urogymnus asperrimus (Elasmobranchii, Dasyatidae) off eastern Australia". Acta Parasitologica 54 (2): 113–118. 
  11. ^ Whittington, I.D. and Kearn, G.C. (Mar. 2009). "Two new species of Neoentobdella (Monogenea: Capsalidae: Entobdellinae) from the skin of Australian stingrays (Dasyatidae)". Folia Parasitologica 56 (1): 29–35. 
  12. ^ Michael, S.W. (1993). Reef Sharks & Rays of the World. Sea Challengers. p. 83. ISBN 0930118189. 
  13. ^ Stone, G.C. and LaRocca, D.J. (1999). A Glossary of the Construction, Decoration and Use of Arms and Armor in All Countries and in All Times. Courier Dover Publications. p. 537. ISBN 0486407268. 
  14. ^ Carpenter, G.H. and Praeger, R.L., ed (1896). The Irish Naturalist. Eason & Son. p. 167. 
  15. ^ Kingsley, J.S. (1888). The Riverside Natural History. Kegan Paul, Trench. p. 89. 
  16. ^ Memoir III – Australian Museum, Sydney – The Atolls of Funafuti, Ellice Group: Its Zoology, Botany, Ethnology, and General Structure. The Trustees. 1900. p. 201. 
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