Terra - Um Planeta Maravilhoso
WADI AL-HITAN: O VALE DAS BALEIAS - EGIPTO
Fonte: Amusing Planet
Texto: Português / Inglês
PORTUGUÊS
Os desertos do Egito contém alguns dos sítios paleontológicos mais bem
preservadas do mundo um dos quais é Wadi al-Hitan ou o Vale das Baleias.
Isso vale remoto no deserto ocidental, cerca de 150 km ao sudoeste de
Cairo, contém valiosa colecção de fósseis e ossos de uma extinta,
subordem das baleias, chamada de archaeoceti. Estes fósseis
explica um dos maiores mistérios da evolução das baleias: a emergência
da baleia como um mamífero de longo curso a partir de uma vida anterior
como um animal terrestre. Wadi Al-Hitan é o site mais importante no
mundo para a demonstração deste estágio de evolução. Ela retrata
vividamente a forma ea vida dessas baleias durante a sua transição.
Nenhum outro lugar no mundo produz o número, a concentração ea qualidade
dos fósseis, como é a sua acessibilidade e ambiente em uma paisagem
atraente e protegido.
INGLÊS:
The deserts of Egypt contains some of the best preserved
paleontological sites in the world one of which is Wadi al-Hitan or the
Valley of Whales. This remote valley in the Western Desert, some 150 km
southwest of Cairo, contains valuable collection of fossils and bones of
a now extinct, suborder of whales, called the archaeoceti.
These fossils explains one of the greatest mysteries of the evolution of
whales: the emergence of the whale as an ocean-going mammal from a
previous life as a land-based animal. Wadi Al-Hitan is the most
important site in the world for the demonstration of this stage of
evolution. It portrays vividly the form and life of these whales during
their transition. No other place in the world yields the number,
concentration and quality of such fossils, as is their accessibility and
setting in an attractive and protected landscape.
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The fossils of Wadi Al-Hitan dating back to 50 million years show the youngest archaeocetes,
in the last stages of evolution from land animals to a marine
existence. They already display the typical streamlined body form of
modern whales, whilst retaining certain primitive aspects of skull and
tooth structure, as well as hind legs. Many of the whale skeletons are
in good condition as they have been well preserved in the rock
formations. Semi-complete skeletons are found in the valley and in some
cases, even stomach contents are preserved. Fossil of other early
animals such as those of sharks, crocodiles, sawfish, turtles and rays
found at Wadi al-Hitan makes it possible to reconstruct the surrounding
environmental and ecological conditions of the time.
There is
considerable evidence which indicates that the basin of Wadi Hitan was
submerged in water some 40 to 50 million years ago. At that time, the
so-called Tethys Sea reached far south of the existing Mediterranean.
The Tethys Sea is assumed to have retreated north and over the years
deposited thick sediments of sandstone and limestone visible in rock
formations in Wadi Hitan.
Geological studies have been carried
out in the area since the 1800's, and the first skeletons were found
around 1830 but were never collected due to the difficult accessibility
to the site at that time. At first, it was thought to be a huge marine
reptile. It was only later in 1902, that the species were identified as
whales. For the next 80 years they attracted relatively little interest,
largely due to the difficulty of reaching the area. In the 1980s
interest in the site resumed as four wheel drive vehicles became more
readily available.
Wadi Al-Hitan, now a Unesco World Heritage site, is visited by only 1,000 people each year.
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Sources: UNESCO / Tour Egypt / Photo credit
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