Cetotherium BW

''Cetotherium'' ("whale beast") is an extinct genus of baleen whales from the family Cetotheriidae.

Taxonomy

The family Cetotheriidae and the genus ''Cetotherium'' (sensu lato) have been used as wastebaskets for all kinds of baleen whales, most notably by , Spassky (1954) and . Based on more recent phylogenetic studies and revisions of many 19th century genera, much smaller monophyletic Cetotheriidae and ''Cetotherium'' sensu stricto is limited to a single or only a few species. For example, included only ''C. rathkii'' and ''C. riabinini'' in the genus and only ten genera in the family.

Cetotheriidae were thought to have gone extinct during the Pliocene until 2012, when it was hypothesized that the pygmy right whale was the sole surviving species of this family.

Formerly assigned to ''Cetotherium''

The following species were originally described as nominal species of ''Cetotherium'' but have been either reassigned to other genera or removed from ''Cetotherium'':

* ''Cetotherium furlongi'' Kellogg, 1925, is known from a partial skull from the Burdigalian of the Vaqueros Formation in California, but the holotype is lost.
* ''Cetotherium gastaldii'' Strobel, 1875, known from the early Pliocene-age Sabbie d'Asti Formation of the Piedmont region in Italy, is now the type species of the eschrichtiid genus ''Eschrichtioides''.
* ''Cetotherium klinderi'' Brandt, 1871,Brandt, J. F. 1871. Bericht uber den Fortgang meiner Studien uber di Cetaceen, welche das grosse zur Tertiarzeit von Mitteleuropa bis Centralasien hinein ausgedehnte Meeresbechen bevolkerten. Bulletin de l'Académie Impériale de Saint-Pétersbourg 16: 563–566. is known from an isolated earbone from Miocene sediments in Chişinău, Moldova. Although fragmentary, it is not congeneric with the two species of ''Cetotherium''.
* ''Cetotherium maicopicum'' Spasski, 1951, based on a specimen from the late Miocene of the Russian Caucasus, was reassigned to the genus ''Kurdalagonus'' from the same region in 2012, although Gol'din and Startsev (2016) have questioned this referral.
* ''Cetotherium mayeri'' Brandt, 1871, known from a partial skeleton, has been reassigned to ''Mithridatocetus''.

''Cetotherium incertum'' Brandt, 1873, known from a vertebra, and ''"Ziphius" priscus'' Eichwald, 1840 are ''nomina dubia'', while ''Cetotherium pusillum'' Nordmann, 1860 requires re-assessment.

Evolution

Cetotheres came into existence during the Oligocene epoch. The cetotheres have been divided into two sub-groups. One group includes ''Cetotherium''. From evolutionary perspective, these whales share some characteristics of the Balaenopteridae and Eschrichtiidae.

Paleobiology

Fossil records have revealed a predator-prey relationship between large sharks (e.g. '' O. megalodon'') and Cetotheriids. The raptorial toothed whale, ''Livyatan melvillei'', may too have posed a threat to these whales. The skeleton of an ancient whale was unearthed by archeologists in Crimea in 2018. The whale disappeared 10 million years ago.

See also

* Evolution of Cetaceans

References

Notes

Sources

*Barry Cox, Colin Harrison, R.J.G. Savage, and Brian Gardiner. (1999): The Simon & Schuster Encyclopedia of Dinosaurs and Prehistoric Creatures: A Visual Who's Who of Prehistoric Life. Simon & Schuster.
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{{Taxonbar, from=Q478604

Baleen whales
Miocene cetaceans
Neogene mammals of North America
Prehistoric cetacean genera
Fossil taxa described in 1843