''Scaldicetus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of highly predatory

macroraptorial sperm whale Macroraptorial sperm whales were highly predatory whales of the sperm whale superfamily (Physeteroidea) of the Miocene epoch (geology), epoch that hunted large marine mammals, including other whales, using their large teeth. They consist of five g ...

. Although widely used for a number of extinct physeterids with primitive dental morphology consisting of enameled teeth, ''Scaldicetus'' as generally recognized appears to be a

wastebasket taxon Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically define ...

filled with more-or-less unrelated primitive sperm whales.

Taxonomy

''Scaldicetus'' is known from the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...

deposits of Western Europe, the U.S. (

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, a ...

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; ...

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the East Coast of the United States, Atlantic Coast and the Appalachian Mountains. The geography an ...

), Baja Peninsula, Peru,

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

, and Japan. However, ''Scaldicetus'' is probably a grade taxon, and fossil teeth assigned to it (largely due to the lack of distinguishing characteristics in fossil teeth alone) probably represent more-or-less unrelated sperm whales united by their primitive characteristics rather than actual ancestry. Consequently, this would inflate the genus's distribution. The name ''Scaldicetus caretti'' was coined in 1867 from numerous

sperm whale 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 famil ...

teeth collected in

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago (Mya) to the beginning of the present Quaternary Period Mya. ...

deposits near Antwerp, Belgium probably from the early-to-middle Miocene Bercham Formation. However, some of these remains may have been reworked and redeposited into younger rocks. More remains also near Antwerp from the Diest Formation date to the

Tortonian The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian. The Tort ...

(late Miocene).

Synonyms A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are ...

of ''Scaldicetus'' include ''Palaeodelphis'', ''Homocetus'', and ''Eucetus''. The genus ''Physodon'' described by French paleontologist

Paul Gervais Paul Gervais full name François Louis Paul Gervais (26 September 1816 – 10 February 1879) was a French palaeontologist and entomologist. Biography Gervais was born in Paris, where he obtained the diplomas of doctor of science and of medicine ...

in 1872 was previously considered a synonym, but it was declared a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

'' in 2006. ''Scaldicetus'' is sometimes classified into the dubious subfamily Hoplocetinae along with ''

Diaphorocetus ''Diaphorocetus'' is an extinct genus of odontocete cetacean belonging to Physeteroidea. Its remains were found in the Monte León Formation of Argentina, dating to the Early Miocene.Idiorophus'', and '' Hoplocetus'' based on the presence of large, robust, enamel-coated teeth. The

s ''

Livyatan ''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 ...

'', ''

Zygophyseter ''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 gr ...

'', ''

Brygmophyseter ''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'' b ...

'', and ''

Acrophyseter ''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 ...

'' potentially also belong to this subfamily. ''"Ontocetus" oxymycterus'', described from the middle Miocene (

Langhian The Langhian is, in the ICS geologic timescale, an age or stage in the middle Miocene Epoch/ Series. It spans the time between 15.97 ± 0.05 Ma and 13.65 ± 0.05 Ma (million years ago) during the Middle Miocene.GeoWhen (2007) The Langhian was ...

) of Santa Barbara, California, was assigned to ''Scaldicetus'' in 2008, but was subsequently made the

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ...

of a new genus, '' Albicetus''.

Tooth anatomy

Unlike the modern sperm whale which only has teeth on the bottom jaw, ''Scaldicetus'' had teeth in both jaws. The

lectotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes th ...

for ''S. caretti'' had at least 45 teeth in total in its mouth in life. Like other macroraptorial sperm whales but unlike the modern sperm whale, the teeth were covered in a thick enamel coating, about thick. The teeth were moderately curved and were deeply rooted into the skull, implying a strong bite. Like in other sperm whales, tooth dimensions vary widely; for the lectotype: the total length of the tooth root (the part of the tooth beneath the gum line) is between and the maximum total length of the entire tooth is . Like in other macroraptorial sperm whales, tooth size increased from the back of the jaw to the front. The maximum diameter of the crown (the part of the tooth that is visible and erupts from the gum line) ranges from , and diameter was greatest midway up the tooth.

Paleobiology

The teeth of the lectotype of ''S. caretti'' exhibit

vertical root fracture Vertical root fractures are a type of fracture of a tooth. They can be characterized by an incomplete or complete fracture line that extends through the long axis of the root toward the apex. Vertical root fractures represent between 2 and 5 percen ...

s which were probably brought on by chewing hard food or repetitive application of excessive force while chewing or biting. It is likely these injuries were sustained while biting a fairly large vertebrate, such as various marine mammals as other macroraptorial sperm whales are suspected of hunting. However, the

killer whale The orca or killer whale (''Orcinus orca'') is a toothed whale belonging to the oceanic dolphin family, of which it is the largest member. It is the only extant species in the genus '' Orcinus'' and is recognizable by its black-and-white ...

–which preys on large marine mammals–is not known to exhibit these fractures, though this may be because killer whale teeth are more resistant to shock, having a smaller pulp cavity and, thus, a thicker tooth. Further, terrestrial carnivores that chew through bone display these fractures, and those that prey on larger prey have larger tooth roots. Like in the killer whale, ''Scaldicetus'' may have mashed its food in smaller pieces to ease swallowing, which would have increased the risk of hitting bone which would cause such fractures. Like other macroraptorial sperm whales, ''Scaldicetus'' probably occupied the same niche as the killer whale.

Paleoecology

The Deist Formation, judging from the

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is es ...

assemblage, probably represented a shallow sea with volatile

ocean current An ocean current is a continuous, directed movement of sea water generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contou ...

s, moving

sand bar In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It ...

s, and megaripples. Whale remains include a cetotheriid

baleen whale Baleen whales ( systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea ( whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in th ...

, the baleen whale '' Plesiocetus'', a kentriodontid dolphin, and the

beaked whale Beaked whales ( systematic name Ziphiidae) are a family of cetaceans noted as being one of the least known groups of mammals because of their deep-sea habitat and apparent low abundance. Only three or four of the 24 species are reasonably well- ...