The discovery, along with prior fossil finds, suggests the first whale ancestors were full-time land dwellers that might have been related to the early relatives of hoofed animals, such as sheep and cattle. It lived at the land-sea interface and often moved back and forth between the two environments in what is Pakistan today and looked like an improbable cross between a cow, whale, shark, alligator and sea lion.
Saturday, February 7, 2009
' A cross between a cow, whale, shark, alligator and sea lion. '
I talked about how a phylogeny is a testable hypothesis of the evolution of a group, or clade. In the case of marine mammals such as whales the hypothesis is that they evolved from non-aquatic ancestors. Well a paper in PLoS One this week, with the catchy title: New Protocetid Whale from the Middle Eocene of Pakistan: Birth on Land, Precocial Development, and Sexual Dimorphism describes the discovery of a rare fossil of a ancient whale with a fetus still inside that reveals that its species, ancestors to modern whales, gave birth on land 47.5 million years ago.