On the coast of Peru, 200 km from the capital Lima, lies the Pisco area. The Pacific Ocean borders the Pisco-Ica basin, a chain of 14 geological formations from 14 to 3.5 million years old, over a length of 200 km. This exceptional desert area was once part of the ocean floor. The land was pushed upwards by movements in the earth’s crust, and now sits about a hundred metres above sea level.
Along with the seabed the remains of millions of years of sea life have also been pushed up. This is why the area is exceptionally rich in fossils, which the wind gradually exposes in the shifting sands. Mario Urbina Schmitt and Rodolfo Salas Gismondi of the University of San Marcos in Lima and their team of palaeontologists have built up an extremely diverse collection of fossilised vertebrates. The finds include the fossilised skeletons of whales, seals, dolphins, turtles, sharks, penguins and even sloths, which swam around in the coastal water millions of years ago.
Distribution of fossil whales on Cerro Blanco, superimposed on an aerial photo. Red dots = individual whales (N = 180). Black dots = specimens that cannot be determined to be complete whales, usually because of post-exposure erosional damage (N = 166). It appears likely that most whales were essentially complete before the effects of modern erosion processes.
Baleen from Fernanda. Left - surface view of the baleen (~ 8 cm from top to bottom of photo). Upper right - cross section of baleen. The dark colored v-shaped structures are sheets of baleen. Lower right - microscopic enlargement of surface of a sheet of baleen. Notice the fine ridges preserved in the baleen. We found fossilized baleen in several other whales also, but the baleen was best preserved in this whale. This type of preservation requires rapid burial, before the baleen tissue decayed. Fernanda was also buried before the spinal cord decayed, as black mineral replacement of the spinal cord was present in its normal position within the vertebral column (but nowhere else).
-----
That makes sense, doesn’t it? A thicker, heavier plate rode over the top of a thinner, lighter one? Heh...
Yep, and the whales, seals, dolphins, turtles, sharks, penguins and even sloths, which swam around in the coastal water millions of years ago...all went along for the ride!