Time period : 49 - 40 millon years ago
• Maiacetus probably spent much of its life in the water
, returning to land only to mate and give birth.
• It had flipper like limbs , similar to those of a modern
sea or walrus and like some seals .
2) Basilosaurus cetoides
Time period : 40 - 35 millon years ago
• With a streamlined body and paddle-like forelimbs
show Basilosaurus was a fast swimmer.
• Small hind limbs reveal that it descended from land –
dwellers . Scientists first thought that it was a reptile
and had named it “regal lizard “
3) Llanocetus denticrenatus
Time Period : 35 – 30 million years ago
• A skull from the oldest known filter feeding whale
revealed an intermediate step in the evolution of
mysticeti (baleen whales) .
• Its teeth and”baleen” formed a sieve that kept tiny
plankton in while letting water out.
Whales- a brief synopsis
• Whales swim , but their ancestors walked .
• All modern mysticetes are large filter-feeding or
baleen whales, though the exact means by which
baleen is used differs among species .
• All cetaceans, including whales, dolphins and porpoises, are
descendants of land-dwelling mammals of the Artiodactyl
order (even-toed ungulates).
• Both are related to the Indohyus, an extinct semi-aquatic
deer-like ungulate, from which they split around 54 million
• These primitive cetaceans first took to the sea about 50
million years ago and became fully aquatic about 5–10
million years later.
• Their features became adapted for living the marine