Department of Earth Sciences, Indian Institute of Technology, Roorkee 247 677, India.
J Biosci. 2009 Nov;34(5):673-86. doi: 10.1007/s12038-009-0060-0.
The origin of whales (order Cetacea) from a four-footed land animal is one of the best understood examples of macroevolutionary change. This evolutionary transition has been substantially elucidated by fossil finds from the Indian subcontinent in the past decade and a half. Here, we review the first steps of whale evolution, i.e. the transition from a land mammal to obligate marine predators, documented by the Eocene cetacean families of the Indian subcontinent: Pakicetidae, Ambulocetidae, Remingtonocetidae, Protocetidae, and Basilosauridae, as well as their artiodactyl sister group, the Raoellidae. We also discuss the influence that the excellent fossil record has on the study of the evolution of organ systems, in particular the locomotor and hearing systems.
鲸鱼（鲸目）起源于四足陆地动物，是宏观进化变化中研究得最好的例子之一。过去十年半中，印度次大陆的化石发现极大地阐明了这一进化转变。在这里，我们回顾了鲸鱼进化的第一步，即通过印度次大陆的始新世鲸类科（Pakicetidae、Ambulocetidae、Remingtonocetidae、Protocetidae 和 Basilosauridae）以及它们偶蹄目姐妹群 Raoellidae，从陆地哺乳动物过渡到必需的海洋捕食者，记录了这一过程。我们还讨论了极好的化石记录对器官系统进化研究的影响，特别是运动和听觉系统。
