Macroraptorial Sperm Whales/Physeteroids

***Physeter*** is a genus of toothed whales. There is only one living species in this genus: the sperm whale (*Physeter macrocephalus*). Some extremely poorly known fossil species have also been assigned to the same genus including *Physeter antiquus* (5.3 – 2.6 mya) from the Pliocene of France, and *Physeter vetus* (2.6 mya – 12 ka) from the Quaternary of Georgia. *Physeter vetus* is very likely an invalid species, as the few teeth that were used to identify this species appear to be identical to those of another toothed whale, *Orycterocetus quadratidens*.

* Sperm Whale
* livyatan melvillei
* Acrophyseter Robustus
* Zygophyseter Varolai
* Brygmophyseter Shigensis
* Albicetus Oxymycterus
* Acrophyseter Deinodon
* Aulophyseter Morricei
* Miophyseter Chitaensis

## Sperm Whale

### location

all deep oceans, from the equator to the edge of the pack ice in the Arctic and Antarctic

The **sperm whale** or **cachalot** (***Physeter macrocephalus***) is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus *Physeter* and one of three extant species in the sperm whale family, along with the pygmy sperm whale and dwarf sperm whale of the genus *Kogia*.

The sperm whale is a pelagic mammal with a worldwide range, and will migrate seasonally for feeding and breeding. Females and young males live together in groups, while mature males (bulls) live solitary lives outside of the mating season. The females cooperate to protect and nurse their young. Females give birth every four to twenty years, and care for the calves for more than a decade. A mature sperm whale has few natural predators, although calves and weakened adults are sometimes killed by pods of killer whales (orcas).

Mature males average 16 metres (52 ft) in length but some may reach 20.7 metres (68 ft), with the head representing up to one-third of the animal's length. Plunging to 2,250 metres (7,382 ft), it is the third deepest diving mammal, exceeded only by the southern elephant seal and Cuvier's beaked whale. The sperm whale uses echolocation and vocalization as loud as 230 decibels (re 1 µPa m) underwater. It has the largest brain on Earth, more than five times heavier than a human's. Sperm whales can live 70 years or more.

### location

southeastern Pacific Ocean

***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. 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, South Africa, and Australia imply that either it or a close relative survived into the Pliocene, around 5 mya, and was present throughout the Southern Hemisphere. 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.

*Livyatan*'s total length has been estimated to be about 13.5–17.5 m (44–57 ft), similar to that of the modern sperm whale (*Physeter macrocephalus*), making it one of the largest predators known to have existed. The teeth of *Livyatan* measured 36.2 cm (1.2 ft), and are the largest biting teeth of any known animal, excluding tusks. It is distinguished from the other raptorial sperm whales by the basin on the skull, spanning the length of the snout. The spermaceti organ, contained in that basin is thought to have been used in echolocation and communication, or for ramming prey and other sperm whales. The whale may have interacted with the large extinct shark Megalodon (*Otodus megalodon*), competing with it for a similar food source. Its extinction was probably caused by a cooling event at the end of the Miocene period causing a reduction in food populations. The geological formation where the whale has been found has also preserved a large assemblage of marine life, such as sharks and marine mammals.

## Acrophyseter Robustus

### length and weight

13-15 ftTBA(can't find a straight answer)

### location

the coast of Peru

***Acrophyseter*** is a genus of extinct sperm whales that lived in the Late Miocene off the coast of Peru comprising two species: *A. deinodon* and *A. robustus*. It is part of a group of macroraptorial sperm whales which all shared several features for the purpose of hunting large prey, such as deeply-rooted and thick teeth. *Acrophyseter* measured 4–4.5 metres (13–15 ft), making it the smallest raptorial sperm whale. Because of its short pointed snout, and its strong curved front teeth, it probably fed on the large marine vertebrates of its time, such as seals and other whales. The genus *Acrophyseter* houses two species. The type species, *A. deinodon*, was discovered in the Sud-Sacaco locality of the Pisco Formation in Peru, dating back to the Tortonian–Messinian stages of the Miocene around 8.5–6.7 million years ago (mya); the holotype specimen, MNHN SAS 1626, represents a mature individual and consists of a skull and jaw with most of the teeth intact. The second species, *A. robustus*, is known from a skull also from the Pisco Formation in the Cerro la Bruja locality, named MUSM 2182, dating back to the Serravallian–Tortonian stages of the Miocene, older than at least 9.2 mya. A second *A. deinodon* specimen of a right parietal bone from the Aguada de Lomas locality was named MNHM F-PPI 272 and dated to the Messinian 6.9–6.7 mya, though it is possible it actually represents *A. robustus*. MUSM 1399 of a skull with the front half of the snout missing from the Cerro La Bruja locality was referred to *Acrophyseter* but has not been given a species designation. *A. robustus* had a more pointed snout, straighter teeth, a decreasing width of the mandible from front to back, a groove on the side of its snout, and a more well-defined supracranial basin which housed the melon organ than *A. deinodon*.

The genus name *Acrophyseter* is derived from the Greek *akros*–meaning acute, which describes the short, pointed, upturned snout–and *physeter*–which is the genus name for the modern sperm whale *Physeter macrocephalus*. The species name *deinodon* is from the Greek *deinos*–meaning terrible–and *odon*–tooth.

### location

the ancient seas of Italy

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.

## Brygmophyseter (Naganocetus) Shigensis

### location

he Middle Miocene deposits of the Bessho Formation of Japan

***Brygmophyseter***, known as the **biting sperm whale**, is an extinct genus of toothed whale in the sperm whale family with one species, ***B. shigensis***. When it was first described in 1994, the species was placed in the genus *Scaldicetus* based on tooth morphology, but this was later revised in 1995. In 2006, it was classified into the genus ***Naganocetus***, which is considered to be a junior synonym. The only known specimen, a nearly complete skeleton, was dated to be around 14–15 million years old. *Brygmophyseter* is thought to have been 6.5–7 meters (21–23 ft) long, and it probably had 11 or 12 teeth in the upper and lower jaws. *Brygmophyseter* is part of a group of macroraptorial sperm whales (often shortened to "raptorial") which tended to be apex predators using their large teeth to catch struggling prey such as whales. It had a spermaceti organ which was probably used for biosonar like in the modern sperm whale. The whale has made an appearance on The History Channel's TV series *Jurassic Fight Club*.

Like other raptorials, *Brygmophyseter* had enamel-coated teeth in both jaws, unlike the modern sperm whale (*Physeter macrocephalus*). It probably had 11 or 12 teeth in each jaw, though no upper teeth were preserved in the holotype. The skull of the holotype measured around 1.5 meters (4.9 ft), and it had an elongated snout. The brow ridge was broad and flat-topped, and the zygomatic process of the squamosal bone on the cheeks was large and robust. The temporal fossa on the sides of the skull were elongated, which may have been plesiomorphic features from archaeocetes, that is, it is an ancestral characteristic of the whale. The right nasal passage was small and was asymmetrical with the left nasal passage, like in the modern sperm whale. Characteristic of sperm whales, it had a deep basin on the top of its skull, known as the supracranial basin. Like in the modern sperm whale, this basin probably held the spermaceti organ, and so the whale had biosonar capabilities. The nuchal crest which is the part of the whale skull which projects upwards on the back end of the skull, behind the supracranial basin, was low and broad. Similar to modern-day toothed whales, but unlike in the modern sperm whale, the shoulder blades were thicker than they were tall.

*Brygmophyseter* is estimated to have been around 6.5–7 meters (21–23 ft) long. The holotype had preserved zero neck vertebrae, ten thoracic vertebrae, ten lumbar vertebrae, and fifteen tail vertebrae. In comparison, the modern sperm whale has eleven thoracic, eight lumbar, and twenty-two tail vertebrae, and the smaller tail in *Brygmophyseter* is probably a primitive characteristic. The vertebra segments increase in height until the seventh lumbar vertebra, then they begin to decrease. In the thoracic vertebrae, with the exception of the tenth one, the width of the segments is larger than the height. The lumbar and tail vertebrae are circular in shape.

The head of the humerus arm bone of *Brygmophyseter* was positioned perpendicular to the shaft. The elbow joint on the humerus was not distinct from the ulna, typical in cetaceans. The ulna was more primitive than that of the modern sperm whale, in that the shaft was longer and more slender, and the head of the bone was smaller.

## Albicetes Oxymycterus

### location

Santa Barbara

***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*.

The type specimen, USNM 10923, consists of a partial skull (mainly remains of the beak) and isolated tooth fragments. Comparing the occipital condyle length with antorbital notch (slits in the skull right before the snout) width of other primitive sperm whale, the total body length is estimated to be between 5.9–6.3 m (19–21 ft). The preserved length of the beak is 81.9 cm (2.69 ft). The whale had a maximum of 18 teeth in either jaw, deeply rooted in exceedingly large tooth sockets.

The genus *Albicetus* derives from the Latin *albus* "white" and *cetus* "whale", and so literally means "white whale". It was named in reference to the antagonist Moby Dick from Herman Melville's novel *Moby-Dick*. This reference was done both in honor of Melville and as a reference to the most notable traits of the Moby Dick–including an "unwonted magnitude", light color, and a crooked and deformed lower jaw–which coincidentally also describe the traits found in the *Albicetus oxymycterus* holotype specimen (the fossils themselves possess a light hue). The species name *oxymycterus* is derived from the Ancient Greek ὀξύς *oxy* "sharp" and μυκτήρ *mycter* "nose".

## Acrophyseter Deinodon

### location

Sud-Sacaco locality of the Pisco Formation in Peru

***Acrophyseter*** is a genus of extinct sperm whales that lived in the Late Miocene off the coast of Peru comprising two species: *A. deinodon* and *A. robustus (this page is about Deinodon)*. It is part of a group of macroraptorial sperm whales which all shared several features for the purpose of hunting large prey, such as deeply-rooted and thick teeth. *Acrophyseter* measured 4–4.5 metres (13–15 ft), making it the smallest raptorial sperm whale. Because of its short pointed snout, and its strong curved front teeth, it probably fed on the large marine vertebrates of its time, such as seals and other whales.

The body length range of *Acrophyseter* lies within 4–4.5 metres (13–15 ft). *A. deinodon* was estimated to be 4–4.3 metres (13–14 ft) using the distance between the cheek bones in comparison to the dimensions of *Zygophyseter*, which is relatively small, being the smallest of the raptorial sperm whales.

Unlike the modern sperm whales, *A. deinodon* had teeth on both its upper and lower jaws. The teeth were robust and deeply set into the roots, particularly the front teeth, the tooth roots were comparatively thick with the thin tooth crown. The front teeth were more conical than the back teeth. The lower back teeth were close together, and the space between the teeth increased from front to back, suggesting they were used for shearing, unlike the suction-feeding modern-day sperm whales which lack teeth in their upper jaws. The front teeth were more worn on the sides, whereas the bottom teeth were more worn along the middle. It had 12 teeth in the upper jaw and 13 teeth in the bottom jaw, and like other raptorials, it had tooth enamel. The premaxillae bore three teeth, and the maxillae had nine teeth. The last bottom teeth may have contacted the roof of the mouth. Discovered along the teeth sockets was buccal exostoses, bony growths, which may have developed during biting to strengthen the teeth, acting as buttresses. The back teeth had larger buccal exostoses as they experienced more pressure during biting. The tooth count of *A. robustus* is unknown though thought to be similar or the same. Cementum was continually added to the teeth as they were growing, as in killer whales (*Orcinus orca*).

Like other sperm whales, *Acrophyseter* had a deep basin on the top of its skull, the supracranial basin. This basin in *Acrophyseter* overhung the orbit around the eye, but did not extend onto the snout, unlike in other raptorials. Unlike later species of sperm whales, *Acrophyseter* had two nostrils. The temporal fossae on the sides of the skull were as high as they were long, unlike in *Zygophyseter* and *Brygmophyseter*, which displaced the brow ridge. The area between the condyloid process, which connects the jaw with the skull, and the teeth was probably where the masseter muscles were. The brow ridge slopes down at an angle of around 55°. The nuchal crest on the back side of the skull had overhung the supracranial basin. The cheekbones were thin plates which limited the ear canals. The snout was short and, unlike in other sperm whales, had a distinct upward curve. Unlike other sperm whales, the top of the premaxillae near the vomer lacked a deep groove. The left nostril was five times bigger than the right nostril, measuring 30 and 7.2 millimetres (1.18 and 0.28 in) across respectively.

## Aulophyseter Morricei

### location

the Miocene formations of the west and east coasts of North America, as well as the Patagonian region of South America.

*Aulophyseter* was a predatory whale similar to a modern day sperm whale,‭ ‬although it probably had a more diverse diet.‭ *‬Aulophyseter* was related to other predatory whales such as *Acrophyseter* and the large *Livyatan*.‭ ‬Some *Aulophyseter* however bear a resemblance to another whale called *Orycterocetus* raising the possibility that these fossils could be synonymous.

      Because *Aulophyseter* is known from both the west and east coast of the United‭ ‬States,‭ ‬it‭’‬s possible that *Aulophyseter* may have migrated through the Central American Seaway.‭ ‬Back in the Miocene higher sea levels meant that what is now Panama was completely submerged.‭ ‬Fossil evidence suggests that many cetaceans passed through the area as well as some of their main predators such as the giant prehistoric shark *C.‭ ‬megalodon*.‭ ‬However as sea levels dropped the‭ ‬Isthmus of Panama was created,‭ ‬which resulted in this migratory route between North and South America being sealed.‭ ‬The closure of the Central American Seaway is seen as the death knell for many species of prehistoric whales as well as the predators that preyed upon them.

## Miophyseter Chitaensis

### length and weight

16 ftMuch like many physeters and Macro sperm whales its weight is unknown

### location

Toyohama Formation, Chita District, Aichi Prefecture

From the Burdigalian, lower Miocene. This one did not form part of the macroraptorial clade but almost 5 m long, it would have been a predator to reckon with.- Jaime Bran

***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.