Zygophyseter

Zygophyseter varolai is an extinct cetacean, similar to the sperm whale. The common name of "killer sperm whale" refers both to its relation to modern day sperm whales, and to its similarity in size to and its "probable similar feeding adaptation to the extant delphinid killer whale (Orcinus orca)".

Etymology
The genus name Zygophyseter emphasizes the elongation of the zygomatic process of the only known species Zygophyseter varolai, while the term Physeter refers to the type genus of the family Physeteridae. The Latin species name honors the discoverer Angelo Varola.

Fossil records
The genus Zygophyseter is known in the fossil records on the basis of an almost complete skeleton of Zygophyseter varolai, discovered in Southern Italy in the marine lime mudstone of the Pietra Leccese Formation and described in 2006 by G. Bianucci and W. Landini. This species dates back to the Tortonian Age of the Late Miocene Epoch (age range from 11.608 to 7.246 millions years ago).