Name: Ambulocetus
(Walking whale).
Phonetic: Am-bu-loh-cee-tuss.
Named By: Thewissen et al - 1996.
Classification: Chordata, Mammalia, Cetacea,
Archaeoceti, Ambulocetidae, Ambulocetinae.
Species: A. natans (type).
Type: Carnivore.
Size: 3 meters long.
Known locations: Pakistan.
Time period: Ypresian of the Eocene.
Fossil representation: Several individuals with
partial remains, one specimen with a much more complete skeletal
frame.
Ambulocetus
is a very important transitional fossil as it displays the link between
terrestrial mammals and the early whales.
Ambulocetus
acquired its
name from the idea that it could both swim by undulating its back
as well as leave the water and walk on land. However a 2016 study by
Ando & Fujiwara suggests that Ambulocetus
was more aquatic than
terrestrial, perhaps even exclusively aquatic.
The
ear structure of
Ambulocetus is very interesting as it appears to
have only worked while
it was underwater.The
skull of Ambulocetus is
arranged in such a way that it could swallow food while underwater.
This was achieved by the arrangement of air passages in the snout.
The teeth were also very similar to other early cetaceans and a
chemical analysis of these teeth has shown them to have been exposed to
both fresh and salt water. This implies that Ambulocetus
was active
in river estuaries where fresh meets salt water, but can also suggest
that Ambulocetus was a go anywhere predator. Other
primitive whales important to the study of whale evolution include
Pakicetus
and Rodhocetus.
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More information on these whales can
be found on their respective pages; 1 - Pakicetus, 2 - Ambulocetus, 3 - Rodhocetus, 4 - Dorudon, 5, Brygmophyseter, 6 - Diorocetus. |
Further reading
- Fossil evidence for the origin of aquatic locomotion in archaeocete
whales - Science 263 (5144): 210–212. - J. G. M. Thewissen, S. T.
Hussain & M. Arif - 1994.
- Ambulocetus natans, an Eocene cetacean (Mammalia)
from Pakistan. -
Courier Forschungsinstitut Senckenberg 191. pp. 1–86 - J. G. M.
Thewissen, S. I. Madar & S. T. Hussain - 1996.
- Farewell to life on land – thoracic strength as a new indicator to
determine paleoecology in secondary aquatic mammals. - Journal of
Anatomy. 229 (6): 768–777. - K. Ando & S.-I. Fujiwara - 2016.
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