Zygophyseter varolai is an extinct sperm whale that lived during the Tortonian age of the Late Miocene 11.2 to 7.6 million years ago.

It was a member of a stem group of fossil macroraptorial sperm whales (often shortened to "raptorial") also including Brygmophyseter, Acrophyseter, and Livyatan.

It probably grew to be around 6.5 to 7 meters (21 to 23 ft) in length and shared some characteristics with other raptorials, such as large teeth with tooth enamel that were functional in both the upper and lower jaws which the modern sperm whale (Physeter macrocephalus) lacks.

It also had a beak, the ability to echolocate prey, and could have probably swum faster than the modern-day sperm whale which can reach 4 kilometers per hour (2.5 mph).

The type and only specimen, labelled MAUL 229/1, is of an almost complete skeleton discovered in southern Italy by geologist Angelo Varola in the marine lime mudstone of the Pietra Leccese Formation near the city of Lecce.

[1] A characteristic of related raptorials, Zygophyseter had buccal exostoses, bony outgrowths in the alveolar ridge in the mouth, which are thought to have increased their bite force.

The zygomatic bone (cheekbone) projects outward (anteriorly), indicating it had a beak, which featured an abrupt narrowing; this may have allowed it to clamp down on prey more effectively.

[1][5] The falciform process on the squamosal bone was large and ventrally facing; as opposed to the ones in the Kogiidae (Kogia and Praekogia) which are either reduced or absent.

[1][5] Zygophyseter is part of a fossil stem group of hyper-predatory macroraptorial sperm whales (often shortened to "raptorial") which also includes Brygmophyseter, Acrophyseter, and Livyatan.

It has been proposed that these raptorials be placed into the extinct, possibly paraphyletic (which would make it invalid) subfamily Hoplocetinae, alongside Scaldicetus, Diaphorocetus, Idiorophus, and Hoplocetus.

This is roughly the same bite force that could be exerted by an adult great white shark that is 5.01–5.36 meters (16.4–17.6 ft) long and is stronger than that in other strong-biting animals like lions, though not as strong as in saltwater crocodiles and Basilosaurus isis.

This strategy is somewhat unique, being absent in modern marine macropredators such as sharks and orcas, which instead use a "grip-and-tear" method that dismembers prey by holding and shaking them, and was only previously present in some basilosaurids.

However, it is likely that the feeding strategy evolved independently in Zygophyseter and related macroraptorial sperm whales, as it was absent in more ancestral genera like Eudelphis.

[2] The Z. varolai specimen from the Pietra Leccese Formation dates back to the Tortonian age of the Late Miocene epoch, around 11.6 to 7.2 million years ago (mya), and most likely inhabited the Paratethys sea.