Albicetus Temporal range: Langhian ~16–14 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓

Reconstruction of skull
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Infraorder:	Cetacea
Genus:	†Albicetus Boersma & Pyenson, 2015
Species:	†A. oxymycterus
Binomial name
†Albicetus oxymycterus (Kellogg, 1925)
Synonyms
Ontocetus oxymycterus Kellogg, 1925 Scaldicetus oxymycterus (Kellogg, 1925)

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.^[1]^[2]

Taxonomy

Etymology

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).^[1]

The species name oxymycterus is derived from the Ancient Greek ὀξύς oxy "sharp" and μυκτήρ mycter "nose".^[1]^[3]

Taxonomic history

The holotype was recovered from an unspecified location in the sea cliffs near the original Santa Barbara Lighthouse in 1909, which is believed to most likely be part of the Monterey Formation. The whale was originally placed in the genus Ontocetus in 1925 by American naturalist Remington Kellogg as O. oxymycterus.^[3]^[4]^[5] This genus was originally thought to represent a sperm whale, however, in 2008, the type species, Ontocetus emmonsi, was discovered to actually be a walrus. The whale was then moved to the wastebasket taxon Scaldicetus,^[6] which consists of various other (more-or-less unrelated) primitive sperm whales with enamel coated teeth. In 2015, the whale was moved to the newly erected genus Albicetus.^[1]

Phylogeny

Albicetus, unlike the modern sperm whale (Physeter macrocephalus), possessed functional and enamel-coated teeth in both jaws. This suggests that it is related to the group of macroraptorial sperm whales which includes Acrophyseter, Brygmophyseter, Livyatan, and Zygophyseter. However, Albicetus is most similar in general shape and characteristics with Aulophyseter morricei, except for the dentition in which the latter possesses only small, vestigial upper teeth lacking enamel. The closest known relative to Albicetus is currently Livyatan.^[1]

Albicetus contains only one species A. oxymycterus.

Physeteroidea

†Eudelphis

	†Zygophyseter

	†Brygmophyseter

†Acrophyseter

†Livyatan

†Albicetus

† 'Aulophyseter' rionegrensis

Physeteridae

†Orycterocetus

	†Idiorophus

	†Physeterula

†Idiophyseter

	Physeter

	†Aulophyseter

†Placoziphius

†Diaphorocetus

Kogiidae

†Aprixokogia

	Kogia

	†Praekogia

†Scaphokogia

†Thalassocetus

Relationships between Albicetus and other physeteroids, macroraptorials are in bold^[1]^[7]^[8]

Description

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).^[1]

The whale had a maximum of 18 teeth in either jaw, deeply rooted in exceedingly large tooth sockets.

Paleoecology

For macroraptorial sperm whales, the presence of large body size along with large tooth size suggests that body size was an adaptation to hunting bigger prey, notably other marine mammals, as opposed to the modern sperm whale where size is possibly an adaptation to deep diving. The Langhian is particularly rich in sperm whale diversity, with Albicetus, Brygmophyseter, and Aulophyseter contemporaneously inhabiting the North Pacific. It is possible these sperm whales exhibited niche partitioning to avoid directly competing for food.^[1]

References

External links

Odontocete genera

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea

Odontoceti

†Agorophius †Ankylorhiza †Archaeodelphis †Argyrocetus †Ashleycetus †Caolodelphis †Chilcacetus †Enigmatocetus †Eoplatanista †Inticetus †Macrodelphinus †Microcetus †Mirocetus †Neosqualodon †Olympicetus †Papahu †Patriocetus †Phoberodon †Phococetus †Prosqualodon †Sachalinocetus †Simocetus †Sulakocetus †Tangaroasaurus
†Xenorophidae	Albertocetus Cotylocara Echovenator Inermorostrum Xenorophus
†Waipatiidae	Awamokoa Ediscetus Nihohae Nihoroa Otekaikea Urkudelphis Waipatia
†Squalodontidae	Eosqualodon Squalodon
†Squaloziphiidae	Crisocetus? Squaloziphius Yaquinacetus
†Eurhinodelphinidae	Ceterhinops Eurhinodelphis Iniopsis Mycteriacetus Phocaenopsis Schizodelphis Vanbreenia Xiphiacetus Ziphiodelphis
Crown-Odontoceti	see below↓

Crown-Odontoceti

Physeteroidea

†Acrophyseter †Albicetus †Brygmophyseter †Eudelphis †Hoplocetus †Livyatan †Miophyseter †Rhaphicetus †Scaldicetus †Zygophyseter
Kogiidae	†Aprixokogia Kogia †Koristocetus †Nanokogia †Platyscaphokogia †Pliokogia †Praekogia †Scaphokogia †Thalassocetus?
Physeteridae	†Aulophyseter †Cozzuoliphyseter †Diaphorocetus †Idiophyseter †Idiorophus †Orycterocetus Physeter †Physeterula †Placoziphius †Thalassocetus?

Platanistoidea

†Aondelphis †Dolgopolis †Ensidelphis †Perditicetus †Eurhinodelphinidae? †Squalodontidae? †Waipatiidae?
†Allodelphinidae?	Allodelphis Arktocara Goedertius Ninjadelphis Zarhinocetus
†Squalodelphinidae?	Furcacetus Huaridelphis Macrosqualodelphis Medocinia Notocetus Phocageneus Squalodelphis
Platanistidae	†Araeodelphis †Dilophodelphis †Grimadelphis †Pachyacanthus? Platanista †Pomatodelphis †Prepomatodelphis †Zarhachis?

Ziphiidae

†Aporotus †Beneziphius †Caviziphius †Chavinziphius †Chimuziphius †Choneziphius †Dagonodum †Globicetus †Imocetus †Messapicetus †Nazcacetus †Nenga †Ninoziphius †Notoziphius †Pterocetus Tasmacetus †Tusciziphius †Xhosacetus †Ziphirostrum
Berardiinae	†Archaeoziphius Berardius †Microberardius
Ziphiinae	†Izikoziphius Ziphius
Hyperoodontinae	†Africanacetus Hyperoodon †Ihlengesi Indopacetus Mesoplodon

Delphinida	see below↓

Delphinida

†Albireo †Atocetus †Brevirostrodelphis †Cammackacetus †Delphinodon †Hadrodelphis †Herbeinodelphis †Liolithax †Lophocetus †Macrokentriodon †Miminiacetus †Odobenocetops †Pictodelphis †Pithanodelphis †Tagicetus †Westmorelandelphis
†Kentriodontidae	Belonodelphis? Kampholophos Kentriodon Platysvercus Sophianacetus Rudicetus Wimahl
Lipotidae	Lipotes †Parapontoporia †Prolipotes

Inioidea

†Awadelphis
Iniidae	†Brujadelphis †Goniodelphis Inia †Ischyrorhynchus †Isoninia? †Isthminia †Kwanzacetus †Meherrinia †Plicodontinia †Saurocetes
Pontoporiidae	†Atocetus? †Auroracetus †Brachydelphis †Piscorhynchus †Pliopontos †Pontistes †Protophocaena †Samaydelphis †Scaldiporia †Stenasodelphis Pontoporia

Delphinoidea

Monodontidae	†Bohaskaia †Casatia Delphinapterus †Denebola †Haborodelphis Monodon
Phocoenidae	†Archaeophocaena †Australithax †Haborophocoena †Lomacetus †Miophocaena Neophocaena †Numataphocoena Phocoena Phocoenoides †Piscolithax †Pterophocaena? †Semirostrum †Septemtriocetus

Delphinidae

†Arimidelphis †Australodelphis †Eodelphinus †Etruridelphis †Hemisyntrachelus Lagenorhynchus †Norisdelphis Orcinus †Platalearostrum †Pliodelphis †Pterophocaena?
Lissodelphininae	Cephalorhynchus Lissodelphis
Delphininae	Delphinus Lagenodelphis Sotalia Sousa Stenella Tursiops
Globicephalinae	Feresa Globicephala Grampus Orcaella Peponocephala Pseudorca Steno

Taxon identifiers

Taxon identifiers
Albicetus oxymycterus	Wikidata: Q22285172 Fossilworks: 333315 GBIF: 8550437
Ontocetus oxymycterus	Wikidata: Q112950961 GBIF: 8865365