When was ambulocetus found

Daily health screens are mandatory to access campus. Range: The few specimens of Ambulocetus natans have all been found in Pakistan, in sediments that were deposited in the warm coastal waters of the Tethys Sea. This part of the Tethys disappeared when the Indian tectonic plate slid into the Eurasian plate, causing the Himalayan Mountains to gradually rise up. Size: Ambulocetus is approximately 10 feet in length, based on a nearly complete skeleton of one individual.

Ambulocetus had a long and flexible neck, front limbs with flexible wrists and fingers, powerful legs with large feet, and a long and robust tail that likely lacked tail flukes. Locomotion: Based on its skeletal proportions, it has been suggested that Ambulocetus moved through the water much like an otter. Like otters, the legs and feet would push backward together, the spine would arch, and the tail would have moved upward. One important difference from otters is that in Ambulocetus the feet, not the tail, would have provided the main force for swimming.

Gingerich suggested instead that Ambulocetus used alternate leg paddling to move through the water i. Most paleontologists think that Ambulocetus could have walked on land, although it was probably slow and awkward. Organized bony struts in the leg bones of Ambulocetus and a solid connection between its pelvis and the base of its spine suggest that it could have supported its body weight on land.

That said, how frequently Ambulocetus traveled on land is unclear. While on land, its elbow and knee were habitually flexed, and its feet were solidly planted on the ground, unlike modern hoofed mammals, which stand on their toes. Fischer, Y. Kolodny, B. Luz, and D. Cetacean bone oxygen isotopes as proxies for Miocene ocean compostion and glaciation.

Palaios 7 5 Thewissen, J. Roe, J. O'Neil, S. Hussain, A. Sahni, and S. Evolution of cetacean osmoregulation. Nature Yoshida, N. Oxygen isotope correlation of cetacean bone phosphate with environmental water. Journal of Geophysical Research 96 C1 The origin of tetrapods. Subscribe to our newsletter. Email Facebook Twitter. Macroevolution through evograms.

Skeletons of two early whales. Photo of Pakicetus and Ambulocetus courtesy of J. Thewissen, from: J. Thewissen, L. Cooper, J. George, and S. From land to water: The origin of whales, dolphins, and porpoises. One fairly complete specimen and several partial skeletons have been found in Pakistan. Having the appearance of a 3 meter foot long mammalian crocodile, it was clearly amphibious, as its back legs are better adapted for swimming than for walking on land, and it probably swam by undulating its back vertically, as otters and whales do.

It has been speculated that Ambulocetids hunted like crocodiles, lurking in the shallows to snatch unsuspecting prey.

Chemical analysis of its teeth shows that it was able to move between salt and fresh water. Scientists consider Ambulocetus to be an early whale because it shares underwater adaptations with them: it 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. In addition, its teeth are similar to those of early cetaceans.

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