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Spadenose shark
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The spadenose shark (Scoliodon laticaudus) is a species of requiem shark, family
Navigation Spadenose shark
Carcharhinidae, and the only member of its genus. It is common in the tropical Indian and western
Main page Pacific Oceans, where it forms large schools in shallow water. A small shark reaching a length of
Contents 74 cm (29 in), the spadenose shark is named for its distinctively flattened, triangular snout. It is a
Featured content predator of small bony fishes and invertebrates. This species exhibits the most advanced mode of
Current events viviparity of any fish, in which the developed embryos form a highly complex placental connection
Random article to the mother at a very small size. Females breed year-round, giving birth to six to 18 pups after a
Donate to Wikipedia gestation period of five to six months. The spadenose shark is harmless to humans and is valued
by artisanal and commercial fishers for its meat and fins. Its abundance ensures it forms a
Interaction significant component of many fisheries in South and Southeast Asia. The International Union for
Conservation of Nature has assessed this species as Near Threatened. Conservation status
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Contents
About Wikipedia
Community portal 1 Taxonomy and phylogeny
Recent changes 2 Distribution and habitat
Contact Wikipedia 3 Description Near Threatened (IUCN 2.3)[1]
4 Biology and ecology Scientific classification
5 Human interactions
Toolbox Kingdom: Animalia
6 References
Phylum: Chordata
What links here
Related changes Taxonomy and phylogeny [edit] Class: Chondrichthyes
Upload file Subclass: Elasmobranchii
Special pages The first scientific description of the spadenose shark was published in 1838 by the German
Order: Carcharhiniformes
Permanent link biologists Johannes Peter Müller and Friedrich Gustav Jakob Henle, in their Systematische
Family: Carcharhinidae
Page information Beschreibung der Plagiostomen. The holotype is presumed to be a 42 cm (17 in)-long stuffed
Cite this page
[2]
specimen in the Zoologisches Museum of Berlin. The generic name Scoliodon is derived from the Genus: Scoliodon
J. P. Müller & Henle, 1837
Greek skolex ("worm") and odon ("tooth"), while the specific epithet laticaudus comes from the
Latin latus ("broad" or "wide") and cauda ("tail"). Other common names used for this species Species: S. laticaudus
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include Indian dog shark, sharp-nosed shark, trowel-nose shark, and yellow dog shark.[3] Binomial name
Create a book Phylogenetic analyses based on morphological and molecular data indicate the spadenose shark Scoliodon laticaudus
Download as PDF is one of the most basal members of its family, along with the related genus Rhizoprionodon and J. P. Müller & Henle, 1838
Printable version
Galeocerdo, the tiger shark.[4] In addition, anatomical similarities suggest this species to be the
closest living relative of the hammerhead sharks, which diverged from the other carcharhinids some
Languages time before the Middle Eocene (48.6–37.2 Ma).[5]
Català
Distribution and habitat [edit]
Deutsch
Español The spadenose shark is found in the western Indo-Pacific from Tanzania to South and Southeast
Français Range of the spadenose shark
Asia, as far east as Java and Borneo and as far north as Taiwan and Japan. It is typically found
Nederlands close to the coast in water 10–13 m (33–43 ft) deep, often close to rocky bottoms. This shark is Synonyms
日本語 frequently reported from the lower reaches of rivers in Malaysia, Sumatra, and Borneo, though
Carcharias macrorhynchos Bleeker, 1852
Русский whether this species is capable of tolerating fresh water like the bull shark (Carcharhinus leucas) is
Carcharias muelleri J. P. Müller & Henle, 1839
ไทย unclear due to a lack of salinity data from these areas. [2][3]
Carcharias palasoora Bleeker, 1853
中文
Carcharias sorrahkowah Bleeker, 1853
Description [edit]
Carcharias sorrakowah* Cuvier, 1817
A small, stocky species, the spadenose shark has a broad head with a distinctive highly flattened,
trowel-shaped snout. The eyes and nares are small. The corners of the mouth are well behind the * ambiguous synonym
eyes and have poorly developed furrows at the corners. There are 25–33 tooth rows in the upper
jaw and 24–34 tooth rows in the lower jaw; each tooth has a single slender, blade-like, oblique
cusp without serrations. The first dorsal fin is positioned closer to the pelvic than the pectoral fins, which are very short and broad. The second
dorsal fin is much smaller than the anal fin. There is no ridge between the dorsal fins. The back is bronze-gray in color, and the belly is white.
The fins are plain but may be darker than the body. The maximum known length is 74 cm (29 in), though there are unsubstantiated reports of
individuals reaching 1.2 m (3.9 ft).[2]
Biology and ecology [edit]
Abundant in many areas, spadenose sharks often form large schools. It feeds mainly on small bony fishes, including anchovies, codlets,
burrowing gobies, and Bombay ducks. Shrimp, crabs, cuttlefish, and stomatopods are also sometimes taken.[2][6] Known parasites of this shark
include the tapeworm Ruhnkecestus latipi,[7] and the larvae of ascaridid roundworms.[8]
The spadenose shark has the most advanced form of placental viviparity known in fish, as measured by the complexity of the placental
connection and the difference in weight between the egg and the newborn young.[9] Newly ovulated eggs measure only 1 mm (0.039 in) in
diameter, while the developing embryos become dependent on their mother for sustenance at a length of only 3 mm (0.12 in). The placental
stalk, formed from the yolk sac, has an unusual columnar structure and is covered by numerous long appendiculae that support a massive
capillary network, providing a large surface area for gas exchange. The placental tissue contacts the uterine wall in a unique structure called the
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2. "trophonematal cup", where nutrients are transferred from the mother's bloodstream into the placenta.[9]
Female spadenose sharks probably mate at least once per year, and breeding takes place year-round. The gestation period of the spadenose
shark is five to six months long, and the young are born at a length of 12–15 cm (4.7–5.9 in). The litter size is six to 18. Males mature sexually
at a length of 24–36 cm (9.4–14 in), and females at a length of 33–35 cm (13–14 in). Estimates of the age at maturity range from six months to
two years. The lifespan may be five years for males and six years for females.[6]
Human interactions [edit]
The spadenose shark is harmless to humans. This common species is taken by artisanal and commercial fisheries across its range, using
floating and fixed gillnets, longlines, bottom nets, fish traps, trawls, and hook-and-line. The meat is eaten or used as bait for other fishes, the fins
are valued for shark fin soup, and the carcasses are processed into fishmeal.[2][10] The meat can also be processed with glacial acetic acid to
obtain a gel powder that can be used as a protein supplement in cereal foods, a biodegradable film for wrapping seafood, or a binder in sausages
and other foods.[11]
Despite its commercial importance, overall fishery statistics for the spadenose shark are lacking. A 1996 report found it to be the most common
coastal shark on Chinese markets, and it is also one of the most common sharks caught off northern Australia.[1][6] Substantial numbers are
caught by Indian and Pakistani fisheries; from 1979 to 1981, an average of 823 tons were caught annually off Verval, India.[6] The spadenose
shark is also caught as bycatch, particularly in gillnet fisheries off Kalimantan.[3] The International Union for Conservation of Nature has
assessed this species as Near Threatened; the spadenose shark's relatively short reproductive cycle may render it more resilient to fishing
pressure than other sharks, though its low fecundity still merits caution.[1] This shark may also be negatively affected by coastal development,
due to its inshore habitat preferences.[6]
References [edit]
1. ^ a b c Simpfendorfer, C. (2000). Scoliodon laticaudus . In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved August 30, 2009.
2. ^ a b c d e Compagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Rome: Food
and Agricultural Organization. pp. 533–535. ISBN 92-5-101384-5.
3. ^ a b c Froese, Rainer, and Daniel Pauly, eds. (2009). "Scoliodon laticaudus" in FishBase. August 2009 version.
4. ^ Carrier, J.C., J.A. Musick and M.R. Heithaus (2004). Biology of Sharks and Their Relatives. CRC Press. pp. 52, 502. ISBN 0-8493-1514-X.
5. ^ Martin, R.A. Hammerhead Taxonomy . ReefQuest Centre for Shark Research. Retrieved on August 30, 2009.
6. ^ a b c d e Fowler, S.L., R.D. Cavanagh, M. Camhi, G.H. Burgess, G.M. Cailliet, S.V. Fordham, C.A. Simpfendorfer, and J.A. Musick (2005). Sharks,
Rays and Chimaeras: The Status of the Chondrichthyan Fishes. International Union for Conservation of Nature and Natural Resources. p. 313.
ISBN 2-8317-0700-5.
7. ^ Caira, J.N. and S.M. Durkin (2006). "A New Genus and Species of Tetraphyllidean Cestode from the Spadenose Shark, Scoliodon laticaudus, in
Malaysian Borneo". Comparative Parasitology 73 (1): 42–48. doi:10.1654/4185.1 .
8. ^ Arthur, J.R., A.T.A. Ahmed (2002). Checklist of the Parasites of Fishes of Bangladesh. Food and Agriculture Organization of the United Nations.
p. 30. ISBN 92-5-104854-1.
9. ^ a b Wourms, J.P. (1993). "Maximization of evolutionary trends for placental viviparity in the spadenose shark, Scoliodon laticaudus".
Environmental Biology of Fishes 38: 269–294. doi:10.1007/BF00842922 .
10. ^ Davidson, A. (2003). Seafood of South-East Asia: A Comprehensive Guide With Recipes (second ed.). Ten Speed Press. p. 125. ISBN 1-58008-
452-4.
11. ^ Sen, D.P. (2005). Advances in Fish Processing Technology. Allied Publishers. p. 499. ISBN 81-7764-655-9.
V TE Extant requiem shark species
Kingdom Animalia Phylum Chordata Class Chondrichthyes Subclass Elasmobranchii Subdivision Selachii Order Carcharhiniformes
Blacknose shark (C. acronotus) Silvertip shark (C. albimarginatus) Bignose shark (C. altimus) Graceful shark (C. amblyrhynchoides)
Grey reef shark (C. amblyrhynchos) Pigeye shark (C. amboinensis) Borneo shark (C. borneensis) Copper shark (C. brachyurus)
Spinner shark (C. brevipinna) Nervous shark (C. cautus) Pacific smalltail shark (C. cerdale) Whitecheek shark (C. dussumieri)
Silky shark (C. falciformis) Creek whaler (C. fitzroyensis) Galapagos shark (C. galapagenisis) Pondicherry shark (C. hemiodon)
Carcharhinus
Finetooth shark (C. isodon) Smoothtooth blacktip shark (C. leiodon) Bull shark (C. leucas) Blacktip shark (C. limbatus)
Oceanic whitetip shark (C. longimanus) Hardnose shark (C. macloti) Blacktip reef shark (C. melanopterus) Dusky shark (C. obscurus)
Caribbean reef shark (C. perezii) Sandbar shark (C. plumbeus) Smalltail shark (C. porosus) Blackspot shark (C. sealei)
Night shark (C. signatus) Spottail shark (C. sorrah) Australian blacktip shark (C. tilstoni)
Galeocerdo Tiger shark (G. cuvier)
Borneo river shark (G. fowlerae) Ganges shark (G. gangeticus) Northern river shark (G. garricki) Speartooth shark (G. glyphis)
Glyphis
Irrawaddy river shark (G. siamensis)
Isogomphodon Daggernose shark (I. oxyrhynchus)
Lamiopsis Broadfin shark (L. temminckii) Borneo broadfin shark (L. tephrodes)
Loxodon Sliteye shark (L. macrorhinus)
Nasolamia Whitenose shark (N. velox)
Negaprion Sicklefin lemon shark (N. acutidens) Lemon shark (N. brevirostris)
Prionace Blue shark (P. glauca)
Milk shark (R. acutus) Brazilian sharpnose shark (R. lalandii) Pacific sharpnose shark (R. longurio) Grey sharpnose shark (R. oligolinx)
Rhizoprionodon
Caribbean sharpnose shark (R. porosus) Australian sharpnose shark (R. taylori) Atlantic sharpnose shark (R. terraenovae)
Scoliodon Spadenose shark (S. laticaudus) Pacific spadenose shark (S. macrorhynchos)
Triaenodon Whitetip reef shark (T. obesus)
Categories: IUCN Red List near threatened species Carcharhinidae Viviparous fish
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