Name:
Protocetus
(First whale).
Phonetic: Pro-toe-see-tus.
Named By: Fraas - 1904.
Classification: Chordata, Mammalia, Cetacea,
Archaeoceti, Protocetidae.
Species: P. atavus (type).
Diet: Carnivore.
Size: 2.5 meters long.
Known locations: Egypt. - Mokattam Formation.
Time period: Early Lutetian of the Eocene.
Fossil representation: Single specimen.
The
change from a terrestrial to more aquatic life that began with Pakicetus
through Ambulocetus
continued with the further developments of
Protocetus. The front limbs still had webbed
toes, but the rear
limbs were already greatly reduced in size to the point of them being
vestigial. The caudal vertebrae towards the end of the tail also
hint towards the development of a tail fluke that would have provided
much greater push through the water than its ancestors had. The
nostrils of Protocetus were also faced further back
on the snout for
easier breathing from the water surface. The ears are also best
developed for working while underwater.
Protocetus
was still a dedicated predator with jaws shaped into a long thin
snout, ideally suited for quick opening while submerged since the
narrow jaws would experience far less resistance as they moved through
the water. The teeth at the frontal portion of the jaws were more
suited to prey capture while the teeth at the back were more suited for
slicing. Just like with terrestrial predators the back of the mouth
is the best position for the actual processing teeth since they gain
more benefit from being placed nearer the fulcrum of the jaw
articulation because of the more direct force from the jaw closing
muscles.
Protocetus
is so far only known from earlier in the Eocene, but by the time the
Eocene ended even better developed whales
such as Dorudon,
Zygorhiza
and of course the gigantic Basilosaurus
were all swimming and hunting
in the world’s oceans.
Further reading
- Neue Zeuglodonten aus dem Unteren Mitteleoc�n vom Mokattam bei Cairo.
- Geologische und Palaeontologische Abhandlungen 6(3):199-220 - E.
Fraas - 1904.