Eagle ray
From Wikipedia, the free encyclopedia
| Eagle ray Fossil range: Late Cretaceous–Recent [1] |
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| Spotted eagle ray, Aetobatus narinari | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Superorder: | Batoidea |
| Order: | Rajiformes |
| Family: | Myliobatidae Bonaparte, 1838 |
| Genera | |
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Myliobatis |
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The eagle rays are a group of cartilaginous fishes in the family Myliobatidae, consisting mostly of large species living in the open ocean rather than on the sea bottom.
The taxonomy of this group is uncertain; it is placed either in the order Myliobatiformes or Rajiformes.[2] There are eight genera belonging to the eagle rays: Myliobatis (common eagle rays), Rhinoptera (cownose rays), Pteromylaeus (bull rays), Aetobatus (bonnet rays), Aetomylaeus (smooth tail eagle rays), Californica (bat rays), Mobula (devil rays), and Manta (manta rays). (In some taxonomies the devil rays and manta rays are placed their own family, Mobulidae.)
Eagle rays feed on mollusks and crustaceans, crushing their shells with their flattened teeth, while devil and manta rays filter plankton from the water. They are excellent swimmers and are able to breech the water up to several metres above the surface. Compared with other rays, they have long tails, and well-defined rhomboidal bodies. They are ovoviviparous, giving birth to up to six young at a time. They range from 48 centimetres (19 in) to 9.1 metres (30 ft) in length.[1]
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[edit] Bonnet rays (Aetobatus)
The spotted eagle ray, Aetobatus narinari, also known as the bonnet ray or maylan, belongs to this genus. It is a very beautiful ray, bearing numerous white spots on its inky blue body. It has a span width of 2.5 m (8 ft) and a maximum reported weight of 230 kg (about 507 lbs).[3] Including the tail, it can reach up to 5 m (16 ft) in length. The spotted eagle ray is distributed in the tropical areas of all oceans, including the Caribbean Sea and the Gulf of Mexico.
The genus also includes the much smaller longheaded eagle ray, Aetobatus flagellum, which is a widespread but uncommon species of Indian Ocean and western Pacific coasts. This is considered an endangered species due to huge pressure from fisheries throughout its range.[4]
[edit] Smooth tail eagle rays (Aetomylaeus)
This obscure genus is distributed in the Indian Ocean and the Western Pacific. These rays were named because they lack a sting on the tail. Species include the banded eagle ray, Aetomylaeus nichofii, mottled eagle ray, Aetomylaeus maculatus, and ornate eagle ray, Aetomylaeus vespertilio.
[edit] Manta rays (Manta)
The manta rays are the largest members of the ray family, ranging up to 6.7 m (22 ft) from wing tip to wing tip and weighing up to 1,350 kg (3,000 lb). They inhabit the tropical seas of the world and are often observed around coral reefs.
[edit] Common eagle rays (Myliobatis)
The common eagle ray, Myliobatis aquila, is distributed throughout the Eastern Atlantic, including the Mediterranean Sea and the North Sea. Another important species is the bat eagle ray, Myliobatis californica, in the Pacific Ocean.
These rays can grow extremely large, up to 180 cm including the tail. The tail looks like a whip and may be as long as the body. It is armed with a sting. Eagle rays live close to the coast in depths of 1 to 30 m and in exceptional cases they are found as deep as 300 m. The eagle ray is most commonly seen cruising along sandy beaches in very shallow waters, its two wings sometimes breaking the surface and giving the impression of two sharks traveling together.
[edit] Bull rays (Pteromylaeus)
- For other species that go under the same name, see Bull ray (disambiguation).
The bull ray, Pteromylaeus bovinus, is also named for the shape of its head. It is a very large ray, often 180 cm and sometimes up to 230 cm in length. This ray can be found along Atlantic coasts between Portugal and South Africa. It is also distributed throughout the Mediterranean Sea. Another species in this genus, the rough eagle ray, Pteromylaeus asperrimus, is just 80 cm in length and lives around the Galapagos islands.
[edit] Cownose rays (Rhinoptera)
Cownose rays are named for their ungainly, odd-looking heads. Apart from that they look very much like the above genus. Their whip-like tail is armed with one or more stings. Species include the Javanese cownose ray, Rhinoptera javanica, in the Indian Ocean and the western Pacific, the Australian cownose ray, Rhinoptera neglecta, around the Australian coasts and a species which inhabits the Chesapeake Bay, Rhinoptera bonasus.
[edit] Devil rays (Mobula)
Separate genus of rays. They are similar in appearance to manta rays.
[edit] See also
[edit] References
- ^ a b "Mylobatidae". FishBase. Ed. Rainer Froese and Daniel Pauly. January 2009 version. N.p.: FishBase, 2009.
- ^ Classification in Fishbase
- ^ Florida Museum of Natural History Ichthyology Department
- ^ World Conservation Union "Red List" of threatened species
[edit] External links
- "Myliobatidae". FishBase. Ed. Rainer Froese and Daniel Pauly. August 2005 version. N.p.: FishBase, 2005.
- ARKive - images and movies of the spotted eagle ray (Aetobatus narinari)
