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Science 14 January 1994:
Vol. 263. no. 5144, pp. 210 - 212
DOI: 10.1126/science.263.5144.210
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Articles

Fossil Evidence for the Origin of Aquatic Locomotion in Archaeocete Whales

J. G. M. Thewissen 1, S. T. Hussain 2, and M. Arif 3

1 Department of Anatomy, Northeastern Ohio Universities College of Medicine, Box 95, Rootstown, OH 44272
2 Department of Anatomy, College of Medicine, Howard University, Washington, DC 20059
3 Stratigraphy/Paleontology Branch, Geological Survey of Pakistan, 84 H-8/1, Islamabad, Pakistan

Recent members of the order Cetacea (whales, dolphins, and porpoises) move in the water by vertical tail beats and cannot locomote on land. Their hindlimbs are not visible externally and the bones are reduced to one or a few splints that commonly lack joints. However, cetaceans originated from four-legged land mammals that used their limbs for locomotion and were probably apt runners. Because there are no relatively complete limbs for archaic archaeocete cetaceans, it is not known how the transition in locomotory organs from land to water occurred. Recovery of a skeleton of an early fossil cetacean from the Kuldana Formation, Pakistan, documents transitional modes of locomotion, and allows hypotheses concerning swimming in early cetaceans to be tested. The fossil indicates that archaic whales swam by undulating their vertebral column, thus forcing their feet up and down in a way similar to modern otters. Their movements on land probably resembled those of sea lions to some degree, and involved protraction and retraction of the abducted limbs.

Submitted on October 28, 1993
Accepted on December 3, 1993


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
THE POSTCRANIAL SKELETON OF EARLY EOCENE PAKICETID CETACEANS.
S. I. MADAR (2007)
Journal of Paleontology 81, 176-200
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Land-to-sea transition in early whales: evolution of Eocene Archaeoceti (Cetacea) in relation to skeletal proportions and locomotion of living semiaquatic mammals.
(2003)
Paleobiology 29, 429-454
The Phylogenetic Position of Cetaceans: Further Combined Data Analyses, Comparisons with the Stratigraphic Record and a Discussion of Character Optimization.
M. A. O'Leary (2001)
Integr. Comp. Biol. 41, 487-506
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Review : Evolution of the Motor System: Why the Elephant's Trunk Works Like a Human's Hand.
S. Onodera and T. P. Hicks (1999)
Neuroscientist 5, 217-226
   Abstract »    PDF »
Origin of Whales from Early Artiodactyls: Hands and Feet of Eocene Protocetidae from Pakistan.
P. D. Gingerich, M. u. Haq, I. S. Zalmout, I. H. Khan, and M. S. Malkani (2001)
Science 293, 2239-2242
   Abstract »    Full Text »    PDF »


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