Porpoise
| Porpoise | ||||||||||||
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A porpoise on an Indonesian postage stamp |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Neophocaena phocaenoides | ||||||||||||
| ( Cuvier , 1829) |
The porpoise ( Neophocaena phocaenoides ), also known as the Indian porpoise or Finnless porpoise , is a species of whale from the porpoise family (Phocoenidae) that occurs from the Persian / Arabian Gulf along the north coast of the Indian Ocean to the Formosa Strait in the western Pacific.
For a long time the genus Neophocaena was considered monotypical , but in 2011 the genus was split into the species Neophocaena phocaenoides and Neophocaena asiaeorientalis . The latter has two subspecies: N. a. asiaeorientalis , which occurs very rarely in the Yangtze , and the more common subspecies N. a. sunameri from South Korean and Japanese waters.
description
With a length of only 1.70 meters , the porpoise remains smaller than Neophocaena asiaeorientalis , which reaches a maximum length of about 2.20 meters. The head is small and clearly rounded by the melon . The length of the skull is 18 to 24.5 cm (21 to 29.5 cm for N. asiaeorientalis ). The snout is broad, short and between 6.2 and 9.2 cm long (7.7 to 9.7 cm in N. asiaeorientalis ). For each half of the jaw, 15 to 22 teeth are counted in the upper jaw and 16 to 22 in the lower jaw (16 to 21 or 15 to 20 for N. asiaeorientalis ). Both porpoise species lack the fin , which is why they are also called finless porpoises. For this, they have a zone on their back with rows of tubercles and behind it a low and wide (4.8 to 12 cm) fleshy ridge. The number of rows of tubercles is 10 to 17, in exceptional cases it can be only nine or up to 25 rows . In N. asiaeorientalis , the back ridge begins in front of the middle of the back and is relatively high with a maximum height of 5.5 cm. The tubercles stand on the ridge in one to ten rows, the zone with tubercles is only 2 to 12, in exceptional cases 24 mm wide.
Adult porpoises are dark gray, often almost black, while juveniles are light gray. N. asiaeorientalis , on the other hand, is cream-colored to dark-gray, mostly medium-gray in color and has dark-gray young animals that become lighter with age.
literature
- Jefferson, TA and JY Wang. 2011. Revision of the taxonomy of finless porpoises (genus Neophocaena): the existence of two species . Journal of Marine Animals and Their Ecology 4: 3-16.
Web links
- Finless porpoise on wale.info
- Neophocaena phocaenoides inthe IUCN Red List of Threatened Species 2014.3. Posted by: Wang, JY & Reeves, R., 2011. Retrieved February 1, 2015.