by William T. Kratz

historical research of the whale

fossil records related species

geographic distribution

whale evolution video

In 1693 John Ray classified whales as mammals

In 1859 Charles Darwin believes that whales have similarities to the black bear

In 1883 William Flower suggested whales evolved from ungulates

Philip D. Gingerich Ph.D. researched whale fossils in Pakistan and Egypt from1970s through 1990s

Hans Thewissen led the team that reconstructed the skeleton of the first land mammal ancestor of the whale

Indohyus Pakicetus Ambulocetus

natans Rodhocetus Basilosaurus Dorudon

Indohyus literally means India’s Pig

Fossil founded by Indian geologist Ranga Rao

Skeleton assembled by Hans Thewissen

Fossil dates back 60 mya Even toed ungulate Size of a modern house cat Chemical tests on teeth and bone

analysis revealed that Indohyus spent much of its time wadding in water as a hippo would

Bone structure around the ear revealed unique similarities to that of the modern whale

First Archaeocete Evolved 52 mya Founded by Philip Gingerich in

1983 in Pakistan Pakicetus was about the size of a

wolf Primarily was a land mammal but

spent much time in the water. Had sharp teeth of a carnivore Like Indohyus, had similar bone

structure around ear to that of modern whales

Ambulocetus “walking whale” was found in 1992 by Thewissen

Fossil dates back 49 mya 3 meters in length, hind legs were

well adapted for swimming Skeleton suggests that it hunted

like a crocodilian Ambulocetus had no external ear,

probably kept head close to ground to detect vibrations of land prey

Anatomy of spinal column-swam with tail going up and down

Had an adaptation in the nose that enabled it to swallow underwater, and its periotic bones had a structure like those of whales, enabling it to hear well underwater

49-43 mya in Pakistan by Stromer 1908

Lumbar vertebrae-neural spines higher, more developed tail for swimming

Sacral vertebrae not fused- more flexibility, body developed for swimming

Femur was a third shorter than that of the Ambulocetus’

Skull elongated Ears pushed further back Smaller eyes First ancestor to be more water

orientated that land

Basilosaurus “regal lizard” First skeletal parts found in

Louisiana and Alabama in the 1830’s

Fossil dates back 35-40 mya Could grow up to 20 meters First ancestor that was all aquatic Complete set of hind limb bones

and a pelvis, but very small Formation of blow hole-single

large nostril to the top of the head

First to have tail fluke- due to structure of vertebral proportions

Dorudon was founded by Gingerich in 1994

Fossil dates back 33-40 mya Found in North America, India,

and Pakistan Originally thought to be an

intermediate Basilosarus, ranging from 4-5 meters

Carnivorous, feeding on small fish and mollusks

Looked very similar to modern whales, but lacked the melon organ

Also a completely water orientated mammal.

Distribution of Basilosaurus and Dorudon widely spread vs. Ambulocetus and Rodhocetus restricted to one area in India, Pakistan region

http://www.youtube.com/watch?v=lUuUEo84YlY&feature=related

WHALE EVOLUTION ANIMATION