FOSSIL WHALES OF THE PISCO FORMATION, PERU

This whale (WCBa-32, Carmen) was only partially excavated, because the sediment was very thick to the posterior part of the skeleton. The up side down skeleton is very well articulated and preservation is excellent, except for the tip mandibles and the premaxillary bone which were exposed and modern erosion caused much deterioration. 

The lower jaws, the cervical vertebrae, and the limb bones are all in life position. The vertebral column is articulated and so are the ribs, which show a slight turn over one side caused by the torsion of the carcass after reaching the seafloor. The skull is up side down. One limb is completely missing. Several shark teeth were found associated with this skeleton. 

--------------------

This whale (WCBa-20, Fernanda) is up side down, about 9.5 meters long and very well articulated. The two limbs are preserved and in life position. Several tail bones are missing. Eleven shark teeth were associated with this skeleton. 

Perhaps the most surprising thing of this specimen was the occurrence of the baleen preserved. The baleen is the filtering organ of Mysticeti whales, which feed on small fish and krill that forms the zooplankton. Since the baleen is not made up of bones, but of keratin (the same material as our fingers and hair), it decays much faster than bones, so it is much more difficult to find it as fossil. In this case, the baleen was preserved on top of the right limb, indicating that the filtering plates moved out of the mouth after the death of the whale, and got preserved by rapid sedimentation.

The construction of this HomePage along with any views or opinions expressed are my own. The contents have not been reviewed or approved by the Geoscience Research Institute.