|Araguaian river dolphin|
A recent scientific expedition in the Araguaia River Basin in central Brazil led by Tomas Hrbek of the Universidade Federal do Amazonas in Manaus has resulted in the discovery of a new species of river dolphin. This species was found to be separated from its relatives, the Amazon river dolphin and the Bolivian river dolphin, in the adjoining Amazon Basin to the west by an array of rapids and a small canal thus resulting in its given name: the Araguaian river dolphin. According to Howard Rosenbaum, director of the Wildlife Conservation Society's Ocean Giants program, the discovery is "amazing" because scientists and researchers are beginning to get inside information as to how these animals become distinct species. The team, which discovered the species, conducted their study on the dolphin and concluded that its DNA is adequately different from that of other river dolphins indicating that it is a new species. The amount of difference seen in physical and genetic levels advocates that the Araguaian river dolphin probably separated from other dolphin species more than two million years ago. In addition, the dolphin also demonstrated significant size differences in cranial features and in its number of teeth.
|Range map of South America's river dolphins|
This newly discovered species also marks the first new discovery of a true river dolphin since 1918, when the Yangtze river dolphin was identified in China. However, the Yangtze river dolphin was declared "functionally extinct" in 2006 after scientists could not find even one individual. With the Araguaian river dolphin discovered, scientists warn that it faces the same threats as its relatives which include dam construction and local fishermen who kill them fearing that they compete with them for fish. The recent study revealed that the Araguaia River Basin has been experiencing a great deal of human pressure since the 1960s through agricultural and ranching activities, and the development of hydroelectric dams which have negatively impacted several abiotic and biotic aspects of the river's ecosystem. Dr. Rosenbaum stated that more research needs to be conducted on exactly how these threats may affect the survival of these animals. He further added that as such threats are being addressed, these astounding discoveries are very crucial because they will lead to better protection for the river dolphins.
|Skull and mandible of the Araguaian river dolphin|
It is extremely amazing to know what unexpected surprises are found in continents like South America, which house some of the richest diversities of wildlife in the world. These ecosystems contain such an abundance of different species, that some had been recently discovered and others are still hidden. The Araguaian river dolphin is one of the most recent discoveries not just in South America, but in the world. While its discovery is a major highlight for researchers and scientists, it is also an indication about how these fragile ecosystems that contain such high abundance of wildlife are being tremendously affected by human encroachment. The Yangtze river dolphin has been declared as "functionally extinct" since 2006, due to the continuous impact of threats ranging from construction of dams to pollution. The Araguaian river dolphin must be fully protected by any means necessary to prevent suffering the same fate as its Chinese counterpart. These magnificent animals play a key role in helping maintain the balance of the rivers' ecosystems. Without them, South America's rivers would undergo severe ecological changes such as overpopulation of prey species.
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