The Early Radiations of Cetacea (Mammalia): Evolutionary Pattern and Developmental Correlations

  title={The Early Radiations of Cetacea (Mammalia): Evolutionary Pattern and Developmental Correlations},
  author={J. G. M. Thewissen and E. Mair Williams},
  journal={Annual Review of Ecology, Evolution, and Systematics},
▪ Abstract The origin and early evolution of Cetacea (whales, dolphins, and porpoises) is one of the best examples of macroevolution as documented by fossils. Early whales are divided into six families that differ greatly in their habitats, which varied from land to freshwater, coastal waters, and fully marine. Early cetaceans lived in the Eocene (55–37 million years ago), and they show an enormous morphological diversity. Toward the end of the Eocene the modern cetacean body plan originated… 
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