Pakicetus

Pakicetus Fossil range: Early Eocene
Illustration by Carl Buell, from [2]
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Cetacea Suborder: Archaeoceti Family: Pakicetidae Subfamily: Pakicetinae Genus: Pakicetus Species: P. inachus
Binomial name
Pakicetus inachus Gingerich & Russell, 1981

Reconstruction of Pakicetus

Pakicetus is a genus of extinct cetaceans found in the early Eocene (55.8 ± 0.2 - 33.9 ± 0.1 Ma) of Pakistan, hence their name. The strata where the fossils were found was then part of the coast of the Tethys Sea.

The first fossil, a lone skull, was thought to be a mesonychid, but Gingerich and Russell recognized it as an early cetacean from characteristic features of the inner ear, found only in cetaceans: the large auditory bulla is formed from the ectotympanic bone only. This suggests that it is a transitional species between extinct land mammals and modern cetaceans.

Complete skeletons were discovered in 2001, revealing that Pakicetus was primarily a land animal, about the size of a wolf, and very similar in form to the related mesonychids.

See Also

Evolution of cetaceans

References

• P. D. Gingerich & D. E. Russell (1981). "Pakicetus inachus, a new archaeocete (Mammalia, Cetacea) from the early-middle Eocene Kuldana Formation of Kohat (Pakistan)". Univ. Mich. Contr. Mus. Paleont 25: 235–246. 
• J. G. M. Thewissen, E. M. Williams, L. J. Roe and S. T. Hussain (2001). "Skeletons of terrestrial cetaceans and the relationship of whales to artiodactyls". Nature 413: 277–281.  Abstract

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