LES BREVES :
samedi 28 novembre
Ardipithecus : le singe descend de l’homme !
vendredi 27 novembre
Le singe descend de l’homme
VENDREDI 27 JUIN 2003
ON THE ORIGINS OF WHALES AND DOLPHINS
FROM AN ARCHAIC MARINE FORM
François de Sarre
The natural history of the CETACEA appears not to be the cause of any trouble or controversy among the scientists. They agree on a development from some land mammal ancestors whose structure has been modified to adapt them for full life in the water.
Two main explanations jointly occur for this ancestry : either the CETACEA are coming from ancestors common to those of the today ONGULATA or they evolved from the primitive CARNIVORA, 50 million years ago, for instance from a stage that resembled the modern Phocidae.
Convincing arguments for the first hypothesis seem now to assert from the recent discovery of Ambulocetus remains in Pakistan. They suggest that an evolution of this former genus can be followed up to the level of the nowadays CETACEA.
The aim of the present article is to demonstrate that the latter proposition is quite unacceptable.
On the other hand, an alternative paradigm is now proposed and the possibility evaluated that it was a transformation from former marine bipeds that let into the today whales or dolphins.