| Livyatan | |
|---|---|
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| Cast of skull at theNatural History Museum of the University of Pisa | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Infraorder: | Cetacea |
| Superfamily: | Physeteroidea |
| Genus: | †Livyatan Lambert et al., 2010 |
| Species: | †L. melvillei |
| Binomial name | |
| †Livyatan melvillei Lambert et al., 2010 | |
| Synonyms[1] | |
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Livyatan is anextinctgenus of macroraptorialsperm whale containing one known species:L. melvillei. The genus name was inspired by thebiblical sea monsterLeviathan, and the species name byHerman Melville, the author of the famous novelMoby-Dick about a white bull sperm whale. Herman Melville often referred to whales as "Leviathans" in his book. It is mainly known from thePisco Formation ofPeru during theTortonian stage of theMioceneepoch, about 9.9–8.9 millionyears ago (mya); however, finds of isolated teeth from other locations such asChile,Argentina, theUnited States (California),South Africa andAustralia imply that either it or a close relative survived into thePliocene, around 5 mya, and may have had a global presence. It was a member of a group ofmacroraptorial sperm whales (or "raptorial sperm whales") and was probably anapex 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.
Length estimates for the type specimen ofLivyatan range from 13.5–17.5 m (44–57 ft), comparable to that of the modernsperm whale (Physeter macrocephalus), making it one of the largest predators known. The teeth ofLivyatan measured 36.2 cm (1.19 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 thesnout. Thespermaceti organ contained in that basin is thought to have been used inecholocation and communication, or for ramming prey and other sperm whales. The whale may have interacted with the large extinct sharkmegalodon (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 assharks and othermarine mammals.
In November 2008, a partially preserved skull with the teeth and lower jaw, theholotype specimen (MUSM 1676) ofLivyatan melvillei, was discovered in the coastal desert of Peru in the sediments of thePisco Formation, 35 km (22 mi) southwest of the city ofIca.[1][2] Klaas Post, a researcher for theNatural History Museum Rotterdam in the Netherlands, stumbled across them on the final day of a field trip.[3][4] The fossils were prepared inLima, and are now part of the collection of theMuseum of Natural History, Lima ofNational University of San Marcos.[3][5]
The discoverers originally assigned the English name of the biblical monster, Leviathan, to the whale asLeviathan melvillei. However, the scientific nameLeviathan was preoccupied byLeviathanKoch, 1841, ajunior synonym for themastodon (Mammut).[6] In August 2010, the authors rectified this situation by coining a new genus name for the whale,Livyatan, from the originalHebrew name of the monster. Thespecies namemelvillei is a reference toHerman Melville, author of the bookMoby-Dick, which features a gigantic sperm whale as the mainantagonist.[4][7] The firstLivyatan fossils from Peru were initially dated to around 13–12 million years ago (mya) in theSerravallian Age of the Miocene, but this was revised to 9.9–8.9 mya in theTortonian Age of the Miocene.[8]
During the late 2010s and into the 2020s, fossils of large isolated sperm whale teeth were reported from various Miocene and Pliocene localities, mostly from the Southern Hemisphere. These teeth have been identified as similar in size and shape to those of theL. melvillei holotype and may represent species ofLivyatan. However, it is commonplace that authors do not identify such teeth as a conclusive species ofLivyatan, instead opting to assign anopen nomenclature in which the biological classifications of the specimens are restricted to comparisons or affinities withLivyatan. This is mostly because isolated teeth tend to not be informative enough to be identified at the species level, meaning that there is some undeterminable possibility that they belong to an undescribed close relative ofLivyatan rather thanLivyatan itself.[9][10]
In 2016, inBeaumaris Bay, Australia, a large sperm whale tooth measuring 30 cm (1 ft), specimen NMV P16205, was discovered in Pliocenestrata by a local named Murray Orr, and was nicknamed the "Beaumaris sperm whale" or the "giant sperm whale". The tooth was donated toMuseums Victoria atMelbourne. Though it has not been given a species designation, the tooth looks similar to those ofL. melvillei, indicating it was a close relative. The tooth is dated to around 5 mya,[12][13][14] and so is younger than theL. melvillei holotype by around 4 or 5 million years.[1]
In 2018, palaeontologists led by David Sebastian Piazza, while revising the collections of the Bariloche Paleontological Museum and the Municipal Paleontological Museum of Lamarque, uncovered two incomplete sperm whale teeth cataloged as MML 882 and BAR-2601 that were recovered from theSaladar Member of theGran Bajo del Gualicho Formation in the Río Negro Province ofArgentina, a deposit that dates between around 20–14 mya. The partial teeth measure 142 millimetres (6 in) and 178 millimetres (7 in) in height, respectively. Anatomical analyses of the specimens found that many of their characteristics are identical toL. melvillei except in width, in which the diameter of both teeth are smaller. Because of this, along with only isolated teeth being available, the palaeontologists chose to assign an open nomenclature, identifying both specimens as aff.Livyatan sp.[9][15]
In 2019, palaeontologist Romala Govender reported the discovery of two large sperm whale teeth from Pliocene deposits near theHondeklip Bay village ofNamaqualand inSouth Africa. The pair of teeth, which are stored in theIziko South African Museum and cataloged as SAM-PQHB-433 and SAM-PQHB-1519, measure 325.12 millimetres (13 in) and 301.2 millimetres (12 in) in height, respectively, the latter having its crown missing. Both teeth have open pulp cavities, indicating that both whales were young. The teeth are very similar in shape and size to the mandibular teeth of theL. melvillei holotype, and were identified as cf.Livyatan. Like the Beaumaris specimen, the South African teeth are dated to around 5 mya.[10]
In 2025, Kristin Watmore andDonald Prothero reported a giant sperm whale tooth identified as cf.Livaytan discovered inMission Viejo, California, during housing development during the 1980s and '90s. The tooth resided in the Orange County Paleontological Collection, cataloged as OCPC 3125/66099, and was incomplete but nevertheless measured at least 250 millimetres (10 in) in length and 86 millimetres (3 in) in diameter. Due to poor geographic recording at the time of its discovery, the exact stratigraphic locality was unknown, but it was reported to have come from azone that contains both the mid-MioceneMonterey Formation and youngerCapistrano Formation, the latter dating between 6.6 and 5.8 mya. The authors found the preservation of the tooth to be more consistent with Capistrano Formation fossils. The broken tooth surface exposed layers ofcementum anddentin whose thicknesses fall within the known range ofL. melvillei teeth. OCPC 3125/66099 represented the first evidence that eitherLivyatan orLivyatan-like whales were not restricted to the Southern Hemisphere and likely indicated a possibly global distribution of the cetaceans.[11]
The body length ofLivyatan is unknown because no postcranial skeleton has been found; size estimates are therefore based mainly on the holotype skull. Lambert and colleagues estimated the body length ofLivyatan by comparing it to another macroraptorial sperm whale,Zygophyseter, and modernsperm whales. The authors opted to use the relationship between the bizygomatic width (distance between the oppositezygomatic processes) of the skull and body length because of the variablerostrum length in modern sperm whales and the rostrum ofLivyatan being proportionally shorter. This approach yielded length estimates of 13.5 m (44 ft) using modern sperm whales and 16.2–17.5 m (53–57 ft) usingZygophyseter, with the range driven by the incompleteness of theZygophyseter type specimen.[1][16] It has been estimated to weigh 57 tonnes (62.8 short tons) based on the length estimate of 17.5 m (57 ft).[17] By comparison, the modern sperm whale length measures on average 11 m (36 ft) for females and 16 m (52 ft) for males,[18] with some males reaching up to 20.7 m (68 ft).[19][20][21] The large size was probably ananti-predator adaptation, and allowed it to feed on larger prey.Livyatan is the largest fossil sperm whale discovered, and was also one of the largest-known predators, having the largest bite of anytetrapod.[1][8]
The holotype skull ofLivyatan was about 3 m (9.8 ft) long. Like other raptorial sperm whales,Livyatan had a wide gap in between thetemporal fossae on the sides of the skull and the zygomatic processes on the front of the skull, indicating a large space for holding strongtemporal muscles, which are the most powerful muscles between the skull and the jaw. Thesnout was robust, thick, and relatively short, which allowed it to clamp down harder and better handle struggling prey. The left and rightpremaxillae on the snout probably did not intersect at the tip of the snout, though the premaxillae took up most of the front end of the snout. Unlike in the modern sperm whale, the premaxillae reached the sides of the snout. The upper jaw was thick, especially midway through the snout. The snout was asymmetrical, with the rightmaxilla in the upper jaw becoming slightly convex towards the back of the snout, and the left maxilla becoming slightly concave towards the back of the snout. Thevomer reached the tip of the snout and was slightly concave, decreasing in thickness from the back to the front. A sudden thickening in the middle-left side of the vomer may indicate the location of thenose plug muscles. Eachmandible in the lower jaw was higher than it was wide, with a larger gap in between the two than in the modern sperm whale. Themandibular symphysis, which connects the two halves of the mandibles in the middle of the lower jaw, was unfused. Thecondyloid process, which connects the lower jaw to the skull, was located near the bottom of the mandible, like other sperm whales.[1][8]
Unlike the modern sperm whale,Livyatan had functional teeth in both jaws. The wear on the teeth indicates that the teeth sheared past each other while biting down, meaning it could bite off large portions of flesh from its prey. Also, the teeth were deeply embedded into the gums and could interlock, which were adaptations to holding struggling prey. None of the teeth of the holotype were complete, and none of the back teeth were well-preserved. The lower jaw contained 22 teeth, and the upper jaw contained 18 teeth. Unlike other sperm whales with functional teeth in the upper jaw, none of thetooth roots were entirely present in thepremaxilla portion of the snout, being at least partially in the maxilla. Consequently, its tooth count was lower than those sperm whales, and, aside from the moderndwarf (Kogia sima) andpygmy (K. breviceps) sperm whales, it had the lowest tooth count in the lower jaw of any sperm whale.[1][8]
The most robust teeth inLivyatan were the fourth, fifth and sixth teeth in each side of the jaw. The well-preserved teeth all had a height greater than 31 cm (1 ft), and the largest teeth of the holotype were the second and third on the left lower jaw, which were calculated to be around 36.2 cm (1.2 ft) high. The first right tooth was the smallest at around 31.5 cm (1 ft).[1][8] The Beaumaris sperm whale tooth measured around 30 cm (1 ft) in length, and is the largest fossil tooth discovered in Australia.[13][14] These teeth are thought to be among the largest of any known animal, excludingtusks.[1][8] Some of the lower teeth have been shown to contain a facet for when the jaws close, which may have been used to properly fit the largest teeth inside the jaw. In the front teeth, the tooth diameter decreased towards the base. This was the opposite for the back teeth, and the biggest diameters for these teeth were around 11.1 cm (4.4 in) in the lower jaw. All teeth featured a rapid shortening of the diameter towards the tip of the tooth, which were probably in part due to wear throughout their lifetimes. The curvature of the teeth decreased from front to back, and the lower teeth were more curved at the tips than the upper teeth. The front teeth projected forward at a 45° angle, and, as in other sperm whales, cementum was probably added onto the teeth throughout the animal's lifetime.[1][8]
All tooth sockets were cylindrical and single-rooted. The tooth sockets increased in size from the first to the fourth and then decreased, the fourth being the largest at around 197 mm (7.8 in) in diameter in the upper jaws, which is the largest of any known whale species. The tooth sockets were smaller in the lower jaw than they were in the upper jaw, and they were circular in shape, except for the front sockets, which were more oval.[1][8]
The fossil skull ofLivyatan had a curved basin, known as the supracranial basin, which was deep and wide. Unlike other raptorial sperm whales, but much like in the modern sperm whale, the basin spanned the entire length of the snout, causing the entire skull to be concave on the top rather than creating a snout as seen inZygophyseter andAcrophyseter. The supracranial basin was the deepest and widest over thebraincase, and, unlike other raptorial sperm whales, it did not overhang theeye socket. It was defined by high walls on the sides. The antorbital notches, which are usually slit-like notches on the sides of the skull right before the snout, were inside the basin. A slanting crest on the temporal fossa directed towards the back of the skull separated the snout from the rest of the skull and was defined by a groove starting at the antorbital processes on the cheekbones. The basin had twoforamina in the front, whereas the modern sperm whale has oneforamen on the maxilla, and the modern dwarf and pygmy sperm whales have several in the basin. Thesuture in the basin between the maxilla and theforehead had an interlocking pattern.[8]
Livyatan was part of a fossilstem group ofhyper-predatorysperm whales commonly known asmacroraptorial sperm whales, or raptorial sperm whales, alongside the extinct whalesBrygmophyseter,Acrophyseter andZygophyseter. This group is known for having large, functional teeth in both the upper and lower jaws, which were used in capturing large prey, and had anenamel coating. Conversely, the modernsperm whale (Physeter macrocephalus) lacks teeth in the upper jaw, and the ability to use its teeth to catch prey.[22]Livyatan belongs to a different lineage in respect to the other raptorial sperm whales, and the size increase and the development of thespermaceti organ, an organ that is characteristic of sperm whales, are thought to have evolved independently from other raptorial sperm whales. The large teeth of the raptorial sperm whales either evolved once in the group with abasilosaurid-like common ancestor, or independently inLivyatan. The largetemporal fossa in the skull of raptorial sperm whales is thought to aplesiomorphic feature, that is, a trait inherited from a common ancestor. Since the teeth offoetal modern sperm whales (Physeter macrocephalus) have enamel on them before being coated withcementum, it is thought that the enamel is also an ancient characteristic (basal). The appearance of raptorial sperm whales in the fossil record coincides with the diversification ofbaleen whales in theMiocene, implying that they evolved specifically to exploit baleen whales.[1][8] It has also been suggested that the raptorial sperm whales should be placed into thesubfamilyHoplocetinae, alongside the generaDiaphorocetus,Idiorophus,Scaldicetus andHoplocetus, which are known from the Miocene to the lowerPliocene. However, most of these taxa remain too fragmentary or have been used aswastebasket taxa for non-diagnostic material of stem physeteroids. This subfamily is characterized by their robust and enamel-coated teeth.[23]
The cladograms below are modified from Lambertet al. (2017)[1][8][22] and Paolucci et al. (2025),[24] and represents the phylogenetic relationships betweenLivyatan and other sperm whales, with genera identified as macroraptorial sperm whales in bold.
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Livyatan was anapex predator, and probably had a profound impact on the structuring of Miocene marine communities. Using its large and deeply rooted teeth, it is likely to have hunted large prey near the surface, its diet probably consisting mainly of medium-sized baleen whales ranging from 7–10 m (23.0–32.8 ft) in length. It probably also preyed upon sharks, seals, dolphins and other large marine vertebrates, occupying aniche similar to the modernkiller whale (Orcinus orca). It was contemporaneous with and occupied the same region as theotodontid sharkO. megalodon, which was likely also an apex predator, implyingcompetition over their similar food sources.[1][3][4][25] It is assumed that the hunting tactics ofLivyatan for hunting whales were similar to that of the modern killer whale, pursuing prey to wear it out, and then drowning it.[1][26] Modern killer whales work in groups to isolate and kill whales, but, given its size,Livyatan may have been able to hunt alone.[27]
Isotopic analysis of enamel from a tooth from Chile revealed that this individual likely operated at latitudes south of40°S. Isotopic analyses of contemporary baleen whales in the same formation show that thisLivyatan was not commonly feeding on them, indicating it probably did not exclusively eat large prey, though it may have targeted baleen whales from higher latitudes.[28]
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The supracranial basin in its head suggests thatLivyatan had a largespermaceti organ, a series ofoil andwax reservoirs separated byconnective tissue. The uses for the spermaceti organ inLivyatan are unknown. Much like in the modern sperm whale, it could have been used in the process ofbiosonar to generate sound for locating prey. It is possible that it was also used as a means ofacoustic displays, such as for communication purposes between individuals. It may have been used for acoustic stunning, which would have caused the bodily functions of a target animal to shut down from exposure to the intense sounds.[1][3][8]
Another theory says that the enlarged forehead caused by the presence of the spermaceti organ is used in all sperm whales between males fighting for females during mating season by head-butting each other, includingLivyatan and the modern sperm whale. It may have also been used to ram into prey; if this is the case, in support of this, there have been two reports of modern sperm whales attackingwhaling vessels by ramming into them, and the organ is disproportionally larger in male modern sperm whales.[1][3][8]
An alternate theory is that sperm whales, includingLivyatan, can alter the temperature of the wax in the organ to aid in buoyancy. Lowering the temperature increases the density to have it act as a weight for deep-sea diving, and raising the temperature decreases the density to have it pull the whale to the surface.[1][3][8]
Fossils conclusively identified asL. melvillei have been found in Peru and Chile. However, additional isolated large sperm whale teeth from other locations including California, Australia, Argentina, South Africa and the Netherlands have been identified as a species or possible close relative ofLivyatan.[9][10][11][12][29] On the basis of these fossils, it was likely that the distribution ofLivyatan was widespread. Prior to 2023, paleontologists initially believed that the genus was restricted to the Southern Hemisphere. The warmer waters around the equator have been known to be a climatic barrier for numerous cetaceans since Neogene times, and it was then-hypothesized is thatLivyatan may have been among the cetaceans unable to cross the equatorial barrier. However,collecting bias was another explanation given the apparent rarity and poor fossil record ofLivyatan,[9] now supported by the Northern Hemisphere occurrence in California.[11]
The holotype ofL. melvillei is from theTortonian stage of the UpperMiocene 9.9–8.9 mya in the Pisco Formation of Peru, which is known for its well-preserved assemblage of marine vertebrates. Among the baleen whales found, the most common was an undescribed species ofcetotheriid whale measuring around 5 to 8 m (16 to 26 ft), and most of the other baleen whales found were roughly the same size. Toothed whale remains found consist of beaked whales (such asMessapicetus gregarius), ancientpontoporiids (such asBrachydelphis mazeasi),oceanic dolphins and the raptorial sperm whaleAcrophyseter. All seal remains found represent theearless seals. Also found were large sea turtles such asPacifichelys urbinai, which points to the development ofseagrasses in this area. Partial bones of crocodiles were discovered. Of the seabirds, fragmentary bones ofcormorants andpetrels were discovered, as well as two species ofboobies. The remains of manycartilaginous fish were discovered in this formation, including more than 3,500 shark teeth, which mainly belonged to theground sharks, such asrequiem sharks andhammerhead sharks. To a lesser extent,mackerel sharks were also found, such aswhite sharks,sand sharks andOtodontidae. Many shark teeth were associated with the extinctbroad-tooth mako (Cosmopolitodus/Carcharodon hastalis) and megalodon, and the teeth of these two sharks were found near whale and seal remains.Eagle rays,sawfish andangelsharks were other cartilaginous fish found. Most of thebony fish findings belonged totunas andcroakers.Livyatan and megalodon were likely the apex predators of this area during this time.[25][30]
L. melvillei is also known from theBahía Inglesa Formation of Chile, whose fossiliferous beds are dated between the Tortonian andMessinian 9.03–6.45 mya. Like the Pisco Formation, the Bahía Inglesa Formation famously holds one of the richest marine vertebrate assemblages. Baleen whale remains include ancientminke whales,grey whales,bowhead whales and cetotheriids. Of the toothed whales, five species of pontoporiids as well as beaked whales,porpoises, three other species of sperm whales such as cf.Scaldicetus, and theOdobenocetops have been yielded. Other marine mammals include the marine slothThalassocnus and pinnipeds likeAcrophoca. At least 28 different species of sharks have been described, including many extant ground sharks and white sharks as well as extinct species such as thefalse mako (Parotodus sp.), broad-toothed mako, megalodon and the transitional great whiteCarcharodon hubbelli. Other marine vertebrates includepenguins and other seabirds, and species of crocodiles andghavials.[9][31][32][33][34][35][36]
The Beaumaris sperm whale was found in theBeaumaris BayBlack Rock Sandstone Formation in Australia near the city ofMelbourne, dating to 5 mya in the Pliocene. Beaumaris Bay is one of the most productive marine fossil sites in Australia for marine megafauna. Shark teeth belonging to twenty different species have been discovered there, such as from thewhale shark (Rhincodon typus), thePort Jackson shark (Heterodontus portusjacksoni), the broad-toothed mako and megalodon. Some examples of whales found include the ancient humpback whaleMegaptera miocaena, thedolphinSteno cudmorei and the sperm whalePhysetodon baileyi. Other large marine animals found include ancientelephant seals,dugongs, sea turtles, ancient penguins such asPseudaptenodytes, the extinct albatrossDiomedea thyridata and the extincttoothed seabirds of the genusPelagornis.[37][38][39][40]
The South African teeth attributed as cf.Livyatan are from theAvontuur Member of theAlexander Bay Formation near the village of Hondeklip Bay, Namaqualand, which is also dated to around 5 mya in the Pliocene. The Hondeklip Bay locality enjoys a rich heritage of marine fossils, whose diversity may have been thanks to the initiation of theBenguela Upwelling during the late Miocene, which likely provided large populations of phytoplankton traveling the cold nutrient-rich waters. Cetaceans are the most abundant fauna in the bay, although remains tend to be difficult to conclusively identify. Included are three species ofbalaenopterids including two undetermined species and one identified as cf.Plesiobalaenoptera, an ancient grey whale (cf.Eschrichtius sp.), an undeterminedbalaenid, an unidentified dolphin, and another undetermined species of macroraptorial sperm whale. Other localities of similar age on the South African west coast have also yielded many additional species of balaenopterids and sperm whales as well as ten species of beaked whales. Large sperm whale teeth of up to around ~20 cm (8 in) in length are common in Hondeklip Bay, indicating a high presence of large sperm whales likeLivyatan in the area. The locality has also a high presence of sharks indicated by a large abundance of shark teeth; however, most of these teeth have not been identified. Megalodon teeth have been found in the bay, and evidence from bite marks in whale bones indicate the additional presence of thegreat white shark,shortfin mako and broad-toothed mako. Other marine fauna known in Hondeklip Bay include pinnipeds such asHomiphoca capensis, bony fish and rays.[10][41][42]
Livyatan-like sperm whales became extinct by the early Pliocene likely due to a cooling trend causing baleen whales to increase in size and decrease in diversity, becomingcoextinct with the smaller whales they fed on.[1][3][4][5] Their extinction also coincides with the emergence of the orcas as well as large predatoryglobicephaline dolphins, possibly acting as an additional stressor to their already collapsing niche.[9]
