Cowtail stingray

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Cowtail stingray
Pastinachus sephen2.jpg
Cowtail stingray off Marsa Alam, Egypt
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Superorder: Batoidea
Order: Myliobatiformes
Family: Dasyatidae
Genus: Pastinachus
Species:
P. sephen
Binomial name
Pastinachus sephen
(Forsskål, 1775)
Synonyms

The cowtail stingray (Pastinachus sephen) is a species of stingray in the family Dasyatidae, widespread in the Indo-Pacific region and occasionally entering freshwater habitats. Other common names include banana-tail ray, drab stingray, fantail ray, feathertail stingray, and frill tailed sting ray. This species is sometimes placed in the genus Dasyatis or Hypolophus (an obsolete synonym of Pastinachus). The most distinctive characteristic of the cowtail stingray is the large, flag-like ventral fold on its tail, which is especially prominent when the ray is swimming. This species is targeted by commercial fisheries as a source of high-quality shagreen, a type of leather, and its populations are now under threat from heavy exploitation. [2] [3]

Contents

Distribution and habitat

The cowtail stingray has a widespread distribution in the tropical waters of the Indo-Pacific, from South Africa and the Red Sea to Japan and Australia, including Melanesia and Micronesia. They are amphidromous and known to enter estuaries and rivers. [4] This species is the most commonly reported stingray from fresh water in Southeast Asia, and there is a record from the Ganges River some 2,200 km (1,400 mi) from the sea. [5] [6] They are usually found on sandy bottoms in coastal waters and on coral reefs to a depth of 60 meters (200 feet). [3]

Description

Swimming cowtail stingray, showing ventral tail fold. Pastinachus sephen3.jpg
Swimming cowtail stingray, showing ventral tail fold.

The pectoral fin disk of the cowtail stingray is very thick, with almost straight anterior margins and rounded apices, and measuring 1.1-1.3 times as long as wide. The snout is broadly rounded and blunt. The eyes are very small and widely spaced. The mouth is narrow, with 20 rows of distinctive hexagonal, high-crowned teeth in each jaw and five papillae on the mouth floor. The tail is broad-based, with a filamentous tip and a single venomous spine located well backwards of the pelvic fins. There is no upper tail fold; the high ventral tail fold measures 2-3 times the height of the tail but does not reach the tip. [2] [4] [7]

The disk surface is covered by a broad band of fine dermal denticles extending from near the tip of the snout to the upper surface of the tail, excluding the extreme margins of the disk. Newborns are entirely smooth but develop denticles quickly after birth. Juveniles have four circular tubercles at the center of the disk, which often become indistinct in adults. The coloration is a uniform grayish brown to black above and mostly white below. The tail fold and tip are black. This species may reach 3 meters (9.8 feet) long and 1.8 meters (5.9 feet) across, and 250 kg (550 lb) in weight. [4] [8]

Biology and ecology

Cowtail stingray on a sand flat. Pastinachus sephen.jpg
Cowtail stingray on a sand flat.

Cowtail stingrays are solitary foragers that feed on bony fishes (including leiognathids, Nemipterus , and soles), crustaceans, polychaete worms, sipunculids, and molluscs. [9] The cowtail stingray is in turn preyed upon by various species of hammerhead and requiem sharks, as well as by the bottlenose dolphin (Tursiops aduncus). When threatened, they consistently flee at a 45° angle away from the predator, a trajectory that allows them to maximize the distance covered while still keeping the predator within their field of vision. [10]

Like other stingrays, reproduction in this species is ovoviviparous, with the embryos sustained in late development by histotroph ("uterine milk") delivered via specialized structures. The females giving birth to live young measuring 18 cm (7.1 in) across or more. [2] Single young individuals have been reported year-round in the Strait of Malacca; juveniles have more pointed snouts than adults. [11] Adults are sometimes accompanied by remoras or trevallies. [2] Known parasites of the cowtail stingray include Dendromonocotyle ardea, Decacotyle tetrakordyle, and Pterobdella amara. [12] [13] [14]

Observations of cowtail stingrays in Shark Bay, Australia, show that this species enters shallow, sandy flats during high tide to rest for a minimum of four hours. They often form small groups when resting, particularly when visibility is poor such as in turbid water or under low light conditions. The typical size of such groups is three individuals (larger groups, up to nine, are rare), arranged in a "rosette" formation with their tails pointing outward. This appears to be an anti-predator behavior, as the close circular arrangement of the rays allows them to see predators approaching from any direction. The rosette also orients their less critical tails, containing mechanoreceptors that comprise a secondary warning system, towards potential threats. The members of the group will flee in concert, reducing a predator's ability to target any one individual. [10] Cowtail stingrays also preferentially form mixed-species groups with reticulate whiprays (Himantura uarnak), likely because the whiprays are better able to detect predators due to their longer tails. [15]

An antique round box covered with galuchat. Galuchat 2..jpg
An antique round box covered with galuchat.

Relationship to humans

The serrated spine of the cowtail stingray is potentially dangerous, and this species is regarded as particularly dangerous to handle as its long tail is capable of reaching over its back to strike someone gripping it from the front. [16] Small to moderate numbers of cowtail stingrays are caught as bycatch in trawls and marketed for meat throughout their range, and their tough skin is used to polish wood. [4] [5] This species is also the primary source of shagreen or galuchat, a type of leather, for which it has been valued since ancient times due to the large size and regular arrangement of its dorsal tubercles (called "pearls" in the trade from their nacreous appearance after being rubbed down, hence the old name "pearled ray"). [8] [17] [18]

A boom in the international shagreen trade since the 1990s, with the material being used in many fashion accessories from wallets to fancy pens, has led to enormous numbers of cowtail stingrays being harvested in Southeast Asia. As stingrays are slow-reproducing, long-lived animals, there are fears that this unregulated exploitation is unsustainable and will lead to a population collapse. [19]

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The giant freshwater stingray is a species of stingray in the family Dasyatidae. It is found in large rivers and estuaries in Southeast Asia and Borneo, though historically it may have been more widely distributed in South and Southeast Asia. The largest freshwater fish and the largest stingray in the world, this species grows up to 2.2 m (7.2 ft) across and can reach up to 300 kg (660 lb) in weight. It has a relatively thin, oval pectoral fin disc that is widest anteriorly, and a sharply pointed snout with a protruding tip. Its tail is thin and whip-like, and lacks fin folds. This species is uniformly grayish brown above and white below; the underside of the pectoral and pelvic fins bear distinctive wide, dark bands on their posterior margins.

<i>Himantura</i> Genus of cartilaginous fishes

Himantura is a genus of stingray in the family Dasyatidae that is native to the Indo-Pacific. In a 2016 taxonomic revision, many of the species formerly assigned to Himantura were reassigned to other genera.

<span class="mw-page-title-main">Estuary stingray</span> Species of cartilaginous fish

The estuary stingray, also called the estuary stingaree or brown stingray, is a species of stingray in the family Dasyatidae. Endemic to eastern Australia, it typically inhabits shallow, mangrove-lined tidal rivers, estuaries, and bays in southern Queensland and New South Wales. This yellow-brown to olive ray grows to at least 93 cm (37 in) across. It has a diamond-shaped pectoral fin disc and a mostly smooth, whip-like tail bearing both dorsal and ventral fin folds. It can additionally be identified by its long, narrow nostrils and the row of thorns along the midline of its back.

<i>Himantura fluviatilis</i> Species of cartilaginous fish

The Ganges whip ray is an obscure species of stingray in the family Dasyatidae, apparently endemic to the Ganges River system and adjacent marine waters. With an oval pectoral fin disc and long projecting snout, it closely resembles, and may be the same species as Himantura chaophraya. Growing to 1.4 m (4.6 ft) across, it is a plain dark colour above, and lighter below with wide dark bands on the lateral disc margins. The International Union for Conservation of Nature (IUCN) has listed this species as Endangered, as it faces overfishing and habitat degradation within its heavily populated range.

<span class="mw-page-title-main">Marbled whipray</span> Species of cartilaginous fish

The marbled whipray is a little-known species of stingray in the family Dasyatidae, native to several freshwater rivers in Southeast Asia. This species has an oval pectoral fin disc with an elongated, pointed snout and a very long, whip-like tail without fin folds. It is characterized by numerous heart-shaped dermal denticles and tubercles on its upper surface, as well as a reticulated pattern of brown blotches on a light background. The maximum recorded disc width is 36 cm (14 in). The marbled whipray has been assessed as Endangered by the International Union for Conservation of Nature (IUCN); it is heavily threatened by fishing and habitat loss, degradation, and fragmentation.

<span class="mw-page-title-main">Chupare stingray</span> Species of cartilaginous fish

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<span class="mw-page-title-main">White-edge freshwater whipray</span> Species of cartilaginous fish

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<span class="mw-page-title-main">Whiptail stingray</span> Family of fishes

The whiptail stingrays are a family, the Dasyatidae, of rays in the order Myliobatiformes. They are found worldwide in tropical to temperate marine waters, and a number of species have also penetrated into fresh water in Africa, Asia, and Australia. Members of this family have flattened pectoral fin discs that range from oval to diamond-like in shape. Their common name comes from their whip-like tails, which are much longer than the disc and lack dorsal and caudal fins. All whiptail stingrays, except the porcupine ray, have one or more venomous stings near the base of the tail, which is used in defense. In order to sting their victims, they jerk their tails as the stinger falls off and stays in the wound that they have created. The stinger of a whiptail stingray is pointy, sharp with jagged edges. They range in size from 0.18 to 2.0 m or more across in the case of the smalleye stingray and giant freshwater stingray.

<i>Pastinachus</i> Genus of cartilaginous fishes

Pastinachus is a genus of stingrays in the family Dasyatidae. This genus was long held to be monotypic, containing only the cowtail stingray. Recent studies of Indo-Pacific stingrays have revealed that there are in fact a number of different species of Pastinachus, and that some former junior synonyms may need to be resurrected.

<span class="mw-page-title-main">Mangrove whipray</span> Species of cartilaginous fish

The mangrove whipray or whitetail stingray, is a species of stingray in the family Dasyatidae. It is widely distributed in the Indo-Pacific region from the Red Sea to northern Australia and Micronesia. A benthic inhabitant of shallow inshore waters, juvenile mangrove whiprays favor mangrove and estuarine habitats, while adults favor sandy to rocky areas in lagoons and coral reefs. This species can be identified by its thick, oval pectoral fin disc that is dark gray above with numerous white flecks, and by its relatively short, whip-like tail that is white past the stinging spine. It grows up to 1.4 m (4.6 ft) across.

<span class="mw-page-title-main">Reticulate whipray</span> Species of fish

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<span class="mw-page-title-main">Pink whipray</span> Species of stingray in the family Dasyatidae

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<span class="mw-page-title-main">Jenkins' whipray</span> Species of cartilaginous fish

The Jenkins' whipray is a species of stingray in the family Dasyatidae, with a wide distribution in the Indo-Pacific region from South Africa to the Malay Archipelago to northern Australia. This large species grows to 1.5 m (4.9 ft) across and has a broad, diamond-shaped pectoral fin disc and a whip-like tail without fin folds. It has a band of heart-shaped dermal denticles running from between the eyes to the tail on its upper surface, along with a characteristic row of large spear-like thorns along the midline. It is uniform yellowish brown above, becoming grayish on the tail past the stinging spine, and white below; there is apparently a spotted color variant that had previously been described as a different species, the dragon stingray.

<span class="mw-page-title-main">Freshwater whipray</span> Species of fish

The freshwater whipray is a little-known species of stingray in the family Dasyatidae, found in a number of large rivers and associated estuaries in northern Australia. Until recently, this species was regarded as a regional subpopulation of the similar-looking but much larger giant freshwater stingray of Southeast Asia. Typically reaching 1 m (3.3 ft) across, the freshwater whipray has a distinctively shaped, rounded pectoral fin disc, a projecting snout, and a thin tail without fin folds. It is plain brown above and white below with dark marginal bands. It may occasionally travel onto land and can "breathe" out of water for up to 7 minutes. The freshwater whipray is an active hunter of small fishes and shrimps, and does not currently face substantial conservation threats.

The Hortle's whipray is a little-known species of stingray in the family Dasyatidae, occurring in shallow estuaries and mud flats off southern New Guinea. This species, growing to 71 cm (28 in) across, has a heart-shaped pectoral fin disc with a long, pointed snout and minute eyes. It has a wide dorsal band of dermal denticles extending from in front of the eyes to the tail, as well as scattered sharp denticles on the snout. The underside of the disc is a distinctive bright yellow in color, sometimes with darker markings around the nostrils, mouth, and gill slits. The Hortle's whipray is threatened by extensive seine fisheries and habitat degradation, leading the International Union for Conservation of Nature (IUCN) to assess it as Near Threatened.

<span class="mw-page-title-main">Brown whipray</span> Species of cartilaginous fish

The brown whipray is a species of stingray in the family Dasyatidae, common in inshore, muddy habitats along the northern coast of Australia. It has often been confused in literature for the honeycomb stingray and the black-spotted whipray, which until recently was thought to be the same species. This species has an angular, diamond-shaped pectoral fin disc and a long, very thin tail without fin folds. It is plain brown above, sometimes with white dots or flecks near the edge of the disc, and white below; the tail is dark all over, with alternating dark and light bands near the tip. The maximum recorded disc width is 74 cm (29 in).

<span class="mw-page-title-main">Blackedge whipray</span> Species of cartilaginous fish

The blackedge whipray is a little-known species of stingray in the family Dasyatidae, found in the coastal waters of the Bay of Bengal and the Gulf of Mannar. Attaining a disc width of 1.8 m (5.9 ft), this species has a diamond-shaped disc with two small concavities on either side of the snout tip, and a long, whip-like tail without tail folds. It is characterized by large thorns with star-shaped bases scattered over the disc, and by the wide, black marginal bands on the underside of the disc. The International Union for Conservation of Nature (IUCN) currently lacks sufficient data to assess the blackedge whipray beyond Data Deficient.

<span class="mw-page-title-main">Leopard whipray</span> Species of cartilaginous fish

The leopard whipray is a little-known species of stingray in the family Dasyatidae, found in the Indian and Pacific Oceans from the Andaman Sea to the Coral Triangle. It is found close to shore at depths shallower than 70 m (230 ft), over soft substrates. Attaining a width of 1.8 m (5.9 ft), this species has a diamond-shaped pectoral fin disc with a pointed snout and an extremely long, whip-like tail without fin folds. Adult rays have a leopard-like dorsal pattern of dark brown rings on a yellowish brown background, as well as a row of enlarged, heart-shaped dermal denticles along the midline of the disc. Newborns and small juveniles have large, solid dark spots and few denticles. The leopard whipray is caught by fisheries in many parts of its range, primarily for meat.

<span class="mw-page-title-main">Honeycomb whipray</span> Species of cartilaginous fish

The honeycomb whipray is a species of stingray in the family Dasyatidae, found widely in the shallow coastal waters of the Indo-Pacific from India to the Malay Archipelago. This large species grows to 1.3 m (4.3 ft) across and has a diamond-shaped disc with rounded corners and a projecting, pointed snout. Its tail is long and whip-like, without fin folds. Adults have a striking dorsal color pattern consisting of large, dark brown rings and reticulations delineated by thin yellow lines, while juveniles have a pattern of large dark spots. This ray can also be distinguished from its similar relatives by an enlarged, pearl-like dermal denticle at the center of the back, which is followed by a few thorns. The International Union for Conservation of Nature (IUCN) has assessed the honeycomb whipray as endangered, as it faces heavy fishing pressure and habitat degradation across much of its range.

<i>Brevitrygon walga</i> Species of cartilaginous fish

Brevitrygon walga, the dwarf whipray or mangrove whipray, is a small stingray, a cartilaginous fish in the family Dasyatidae. It is a demersal fish and is found over the continental and insular shelf of the west central Pacific Ocean where it is heavily fished. The IUCN has assessed it as being "near-threatened".

References

  1. ↑ Kyne, P.M., Jabado, R., Bineesh, K.K. & Spaet, J. 2017. Pastinachus sephen. The IUCN Red List of Threatened Species 2017: e.T70682503A109922153. https://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T70682503A109922153.en. Downloaded on 1 October 2017.
  2. 1 2 3 4 Froese, Rainer; Pauly, Daniel (eds.) (2009). "Pastinachus sephen" in FishBase . March 2009 version.
  3. 1 2 Ferrari, A. and A. (2002). Sharks . Firefly Books Ltd. ISBN   978-1-55209-629-1.
  4. 1 2 3 4 Last, P.R.; Compagno, L.J.V. (1999). "Dasyatidae". In Carpenter, K.E.; Niem, V.H. (eds.). The Living Marine Resources of the Western Central Pacific. Vol. 3. Rome: Food and Agricultural Organizations of the United Nations. ISBN   978-92-5-104302-8.
  5. 1 2 Berra, T.M. (2007). Freshwater Fish Distribution. University of Chicago Press. ISBN   978-0-226-04442-2.
  6. ↑ Feibel, C.S. (1993). "Freshwater stingrays from the Plio-Pleistocene of the Turkana Basin, Kenya and Ethiopia". Lethaia. 26 (4): 359–366. doi:10.1111/j.1502-3931.1993.tb01542.x.
  7. ↑ Smith, J.L.B, Smith, M., Smith, M.M. and Heemstra, P. (2003). Smith's Sea Fishes. Struik. ISBN   978-1-86872-890-9.{{cite book}}: CS1 maint: multiple names: authors list (link)
  8. 1 2 Davidson, A. (2003). Seafood of South-East Asia: A Comprehensive Guide with Recipes (Second ed.). Ten Speed Press. ISBN   978-1-58008-452-9.
  9. ↑ Randall, J.E.; Hoover, J.P. (1995). Coastal Fishes of Oman. University of Hawaii Press. ISBN   978-0-8248-1808-1.
  10. 1 2 Semeniuk, C.A.D.; Dill, L.M. (2005). "Cost/benefit analysis of group and solitary resting in the cowtail stingray, Pastinachus sephen". Behavioral Ecology. 16 (2): 417–426. doi: 10.1093/beheco/ari005 .
  11. ↑ Asiatic Society of Bengal (1850). Journal of the Asiatic Society of Bengal. G.H. Rouse, Baptist Mission Press.
  12. ↑ Chisholm, L.A.; Whittington, I.D. (1995). "A revision of Dendromonocotyle Hargis, 1955 (Monogenea: Monocotylidae) with a description of a new species from Pastinachus sephen (Forsskål) (Myliobatiformes: Dasyatididae) from the Great Barrier Reef, Australia". Journal of Natural History. 29 (5): 1093–1119. doi:10.1080/00222939500770461.
  13. ↑ Chisholm, Leslie A.; Whittington, Ian D. (September 1998). "Revision of Decacotylinae Chisholm, Wheeler & Beverley Burton, 1995 (Monogenea: Monocotylidae), including the synonymy of Papillicotyle Young, 1967 with Decacotyle Young, 1967 and a description of a new species from Australia". Systematic Parasitology. 41 (1): 9–20. doi:10.1023/A:1006095219012. S2CID   19978938.
  14. ↑ Burreson, E.M. (2006). "A Redescription of the fish leech Pterobdella amara (=Rhopalobdella japonica) (Hirundinida: Piscicolidae) based on specimens from the type locality in Indian and from Australia". Journal of Parasitology. 92 (4): 677–681. doi:10.1645/GE-802R.1. PMID   16995381. S2CID   21573250.
  15. ↑ Semeniuk, C.A.D.; Dill, L.M. (2006). "Anti-Predator Benefits of Mixed-Species Groups of Cowtail Stingrays (Pastinachus sephen) and Whiprays (Himantura uarnak) at Rest". Ethology. 112 (1): 33–43. doi:10.1111/j.1439-0310.2006.01108.x.
  16. ↑ Cropp, B. (1985). Dangerous Australians: The Complete Guide to Australia's Most Deadly Creatures. Murdoch Books. ISBN   978-0-85835-821-8.
  17. ↑ Royal Zoological Society of Ireland, Dublin Microscopical Club, Belfast Naturalists' Field Club (1896). The Irish Naturalist. Eason & Son, Ltd.{{cite book}}: CS1 maint: multiple names: authors list (link)
  18. ↑ Shaw, G.; Stephens, J.F. (1804). General Zoology. G. Kearsley.
  19. ↑ Reichert, J.S. (November 26, 2005). "It's Stingray, Dahling! A Species In Danger". International Herald Tribune. Retrieved March 1, 2009.
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