''Plesiocetus'' is a

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 extinct

balaenopterid Rorquals () are the largest group of baleen whales, which comprise the family Balaenopteridae, containing ten extant species in three genera. They include the largest animal that has ever lived, the blue whale, which can reach , and the fin whale ...

s found worldwide. It has had a chequered taxonomic history, having served as a wastebasket genus for a handful of

mysticete 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 their ...

species.

Taxonomy

The genus ''Plesiocetus'' was originally coined for three

species from

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. ...

marine deposits in the vicinity of Antwerp,

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to ...

: ''P. garopii'', ''P. hupschii'', and ''P. burtinii''. The three originally included species of ''Plesiocetus'' went about their separate ways. ''P. garopii'' was designated the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

of the genus, while the other two were referred to ''

Cetotherium ''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, mo ...

''.(''P. hupschii'' and ''P. burtinii'' were later assigned to '' Plesiocetopsis'', which was originally erected as a subgenus of ''Cetotherium'') Later, van Beneden noted the similarities of ''Plesiocetus'' with the

fin whale The fin whale (''Balaenoptera physalus''), also known as finback whale or common rorqual and formerly known as herring whale or razorback whale, is a cetacean belonging to the parvorder of baleen whales. It is the second-longest species of c ...

, so he renamed ''Plesiocetus garopii'' into ''Balaenoptera musculoides'', which is invalid under current

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the Int ...

rules. At the same time, he also erected the new species ''P. brialmontii'' on the basis of fragmentary remains, while referring ''Cetotherium dubius'' to ''Plesiocetus''. The taxonomy of ''Plesiocetus'' by now was confused. ''Plesiocetus garopii'' was referred to ''Balaenoptera'' (making ''Plesiocetus'' a synonym of ''Balaenoptera''), while ''P. hupschii'' and ''P. burtinii'' were assigned to ''Cetotherium''. To avoid nomenclatorial complications, ''Plesiocetus hupschii'' was designated the type species of ''Plesiocetopsis'', removing any synonymy between ''Plesiocetus'' and ''Plesiocetopsis''. Recent studies, however, indicate that ''Plesiocetus'' shares no characters with ''Balaenoptera'' to the exclusion of other balaenopterids.Deméré, T., Berta, A. and McGoven, M. R. 2005. The taxonomic and evolutionary history of fossil and modern balaenopteroid mysticetes. Journal of Mammalian Evolution, 12: 99–143.Steeman, M. E. (March 2010). "The extinct baleen whale fauna from the Miocene-Pliocene of Belgium and the diagnostic cetacean ear bones". Journal of Systematic Palaeontology 8 (1): 63–80. doi:10.1080/14772011003594961. For its part, ''P. burtinii'' was referred to '' Aglaocetus'', while ''P. brialmontii'' 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 ...

. These revisions leave ''P. garopii'' the type and only species of ''Plesiocetus''.

Distribution

Fossils of ''Plesiocetus'' have been found in:''Plesiocetus''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cre ...

.org ;Neogene *

Gaimán Formation The Gaiman Formation ( es, Formación Gaiman), in older literature also referred to as Patagonian Marine Formation ( es, Formación Patagonia Marino, ''Patagoniense''), is a fossiliferous geologic formation of the Peninsula Valdés Basin in the ea ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

Berchem Berchem () is a southern district of the municipality and city of Antwerp in the Flemish Region of Belgium. Berchem is located along the old ''Grote Steenweg'' (Dutch for 'Big Paved Road') that has connected Brussels to Antwerp for several centur ...

Diest Diest () is a city and municipality located in the Belgian province of Flemish Brabant. Situated in the northeast of the Hageland region, Diest neighbours the provinces of Antwerp to its North, and Limburg to the East and is situated aroun ...

and Sables d'Anvers Formations,

Navidad Formation Navidad Formation ( es, Formación Navidad) is a marine Neogene sedimentary formation located in Central Chile. The formation is known for its diverse and abundant fossil record and is considered the reference unit for the marine Neogene in Chile ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

* Mont-de-Marsan and Poussan,

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan ar ...

* Eibergen Member,

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

;Quaternary *

Red Crag Formation The Red Crag Formation is a geological formation in England. It outcrops in south-eastern Suffolk and north-eastern Essex. The name derives from its iron-stained reddish colour and ''crag'' which is an East Anglian word for shells. It is part of th ...

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

References

{{Taxonbar, from=Q15697126 Baleen whales Prehistoric cetacean genera Miocene cetaceans Pliocene cetaceans Pleistocene cetaceans Miocene mammals of Europe Pliocene mammals of Europe Pleistocene mammals of Europe Neogene United Kingdom Fossils of Belgium Fossils of Denmark Fossils of France Fossils of Germany Fossils of Italy Fossils of the Netherlands Fossils of England Miocene mammals of North America Pliocene mammals of North America Neogene Mexico Fossils of Mexico Neogene United States Fossils of North Carolina Miocene mammals of South America Neogene Argentina Fossils of Argentina Gaiman Formation Neogene Chile Fossils of Chile Fossil taxa described in 1859