Miocene cetaceans

Livyatan is an extinct genus of macroraptorial sperm whale containing one known species: L. melvillei. The genus name was inspired by the biblical sea monster Leviathan, and the species name by Herman Melville, the author of the famous novel Moby-Dick about a white bull sperm whale. Herman Melville often referred to whales as "Leviathans" in his book. It is mainly known from the Pisco Formation of Peru during the Tortonian stage of the Miocene epoch, about 9.9–8.9 million years ago (mya); however, finds of isolated teeth from other locations such as Chile, Argentina, the United States (California), South Africa and Australia imply that either it or a close relative survived into the Pliocene, around 5 mya, and may have had a global presence. It was a member of a group of macroraptorial sperm whales (or "raptorial sperm whales") and was probably an apex predator, preying on whales, seals and so forth. Characteristically of raptorial sperm whales, Livyatan had functional, enamel-coated teeth on the upper and lower jaws, as well as several features suitable for hunting large prey.

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 is known from a single specimen from the Pietra Leccese Formation in Italy. 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). These were probably used in the capture of large prey, such as large fish, seals, and whales. In fact, its common name, the killer sperm whale, refers to its feeding habits that would have had a resemblance to the modern-day killer whale (Orcinus orca).

Chavinziphius is an extinct genus of ziphiid cetacean known from Messinian age marine deposits in the Pisco Formation in Peru. There is only one known species, Chavinziphius maxillocristatus.

Brujadelphis is an extinct genus of river dolphin-like cetaceans of uncertain family placement from the Late Miocene epoch (Serravallian) of present-day Peru. The type species is Brujadelphis ankylorostris, recovered from the Pisco Formation.

Miophyseter is an extinct genus of sperm whale in the superfamily Physeteroidea. It includes only one species, M. chitaensis, that was described in 2022 from the lower Miocene (Burdigalian) of Toyohama Formation, Chita District, Aichi Prefecture, Japan. This species is known from the well-preserved cranium with detached teeth and ear bones (periotic, tympanic bulla, and malleus). Miophyseter is part of the Physeteroidea stem group, but more closely related to the crown group than to the macroraptorial sperm whales known from middle and late Miocene. Miophyster may have had an adaptation to deep diving and / or developed pterygoid muscles for active biting. The researchers made this conclusion judging by the presence of a deep and large notch on the ventral surface of the palatine bone and pterygoid.

Orcinus meyeri is a fossil species of Orcinus (killer whales) found in the Early Miocene deposits of southern Germany, known from two jaw fragments and 18 isolated teeth. It was originally described as Delphinus acutidens in 1859, but reclassified in 1873. Its validity is disputed, and it may be a synonymous with the ancient sperm whale Physeterula dubusi. It was found in the Alpine town of Stockach in the Molasse basin, which was a coastal area with strong tidal currents.

Chilcacetus is an extinct genus of primitive odontocete known from Early Miocene (Aquitanian) of Peru. Fossils were found in and named after the Chilcatay Formation of the Pisco Basin.

Araeodelphis is an extinct genus of river dolphin from the early Miocene of the East Coast of the United States.

Albicetus is a genus of stem-sperm whales that lived during the Miocene Epoch, around 15 million years ago, and was discovered in Santa Barbara, California in 1909. It was categorized for decades as belonging to a group of extinct walruses erroneously thought to be sperm whales. It was named Albicetus, meaning "white whale", is a reference to the leviathan in Herman Melville's classic 1851 novel Moby-Dick.

Huaridelphis is an extinct genus of river dolphins from the Early Miocene (Deseadan to Friasian in the SALMA classification). The type species is H. raimondii, found in the Chilcatay Formation of the Pisco Basin.