Phylogenetic aspects of Cetacean origins: A morphological perspective

  title={Phylogenetic aspects of Cetacean origins: A morphological perspective},
  author={J. G. M. Thewissen},
  journal={Journal of Mammalian Evolution},
  • J. Thewissen
  • Published 1 September 1994
  • Biology
  • Journal of Mammalian Evolution
The evolutionary steps leading up to the origin of cetaceans involved pervasive changes in the masticatory apparatus, the ear, and limb morphology. These changes bear heavily on the phylogenetic relationships of Cetacea, and are investigated here on the basis of two of its earliest members:Pakicetus andAmbulocetus. A phylogenetic analysis of cetaceans, five groups of mesonychians, and five other groups of ungulates indicates thatPakicetus is the sister group to all other cetaceans, and that… 

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