Taiwan angelshark
The Taiwan angel shark (Squatina formosa), named and described by Shen and Ting in 1972 is a member of the monogeneric family Squatinidae. The Taiwan angel shark is one of four species of Squatina in the waters around Taiwan and Japan (between latitudes 20° N and 24° N). S. formosa are benthic, ray like sharks that grow to be between 1–2 meters in length.
| Taiwan angel shark | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Order: | Squatiniformes |
| Family: | Squatinidae |
| Genus: | Squatina |
| Species: | S. formosa |
| Binomial name | |
| Squatina formosa S. C. Shen & W. H. Ting, 1972 | |
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| Range of Taiwan angel shark (in blue) | |
Taxonomy
In 1972 Shen and Ting named and described the Taiwan angel shark. The species name of formosa was chosen because Taiwan is known as Formosa, and this angel shark is found off of the coast of Taiwan. The strait where the sharks are abundant is the Formosa Strait. The New Japanese name for S. formosa is Taiwan-korozane.
Description
Taiwan angel sharks are ray-like sharks. Since they are benthic sharks, their eyes and spiracles are dorsally located. The dorsal surface is covered in somewhat rough denticles. The overall shape of the head is rounded and about 20 percent of the total body length. The widest part of the head is just before the gill openings. S. formosa also has tubercles in between the mouth and eyes. The teeth of the Taiwan angel shark are small and cone-like without serrations. The teeth form three rows. They have large, broad pectoral fins, spine less dorsal fins, no anal fins, and a caudal fin that is hypocercal (the lower lobe is larger and more pronounced than the upper lobe). Both dorsal fins are lobed and are approximately the same size. An adult Taiwan angel shark can grow to be up to two meters in length. Growth is generally slow and maturity happens later in life. Reproduction is ovoviviparous.
Benthic sharks, like S. formosa tend to be darker in coloration. The Taiwan angel shark is a brown with many black and white splotches on the dorsal side. The abdomen is lighter, pale white, with black splotches.
Distribution and Habitat
Taiwan angel sharks are endemic to the waters off of Taiwan. These sharks like to bury themselves in the sediment as they are ambush predators. They are normally found between 100 and 300 meters, although they could be found in shallower waters as well.
Conservation Status
The range that S. formosa is found in is used by fisheries for bottom trawling. The East China Sea is over fished and this causes a problem for slow growing a late maturing fish like the Taiwan angel shark. As of right now there are no active conservation plans for this endangered species.
References
- Compagno, Dando, & Fowler, Sharks of the World, Princeton University Press, New Jersey 2005 ISBN 0-691-12072-2
- Froese, Rainer and Pauly, Daniel, eds. (2006). "Squatina formosa" in FishBase. July 2006 version.
- Kriwe,t J, Endo, H, & Stelbrink, B. 2010. On the occurrence of the Taiwan angel shark, Squatina formosa Shen & Ting, 1972 (Chondrichtyes, Sqatinidae) from Japan. Zoosystematics and Evolution, 86(1), 117-124.
- Walsh, J & Ebert, D. 2007. A review of the systematics of western North Pacific angel sharks, genus Squatina, with redescriptions of Squatina formosa, S. japonica, and S. nebulosa (Chondrichthyes: Squatiniformes, Squatinidae). Zootaxa 1551: 31-47.
- Walsh, J. & Ebert, D. 2009. Squatina formosa. The IUCN Red List of Threatened Species 2009: e.T161456A5428391. http://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161456A5428391.en.