Semirostrum

Vigilance
Semirostrum ceruttii is highly distinctive due to the extremely long symphysis on the lower jaw, reaching lengths of 85 centimeters, while that of a modern porpoise are 1-2 centimeters long. The main hypothesis regarding its use is that it probed along the sediment in
the murky estuaries and shores of what is now California in search of food, which would easily be scooped up the symphysis and into the jaws.