family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
of baleen whales (parvorder Mysticeti). The family is known to have existed from the
Late Oligocene
The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/ Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage ...
phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
studies conducted by recovered the living
pygmy right whale
The pygmy right whale (''Caperea marginata'') is a species of baleen whale. It may be a member of the cetotheres, a family of baleen whales which until 2012 were thought to be extinct; ''C. marginata'' has otherwise been considered the monotyp ...
as a member of Cetotheriidae, making the pygmy right whale the only living cetotheriid, other authors either dispute this placement or recover Neobalaenidae as a sister group to Cetotheriidae.
Taxonomy
After its description by Brant in 1872, Cetotheriidae was used as 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 defined ...
for baleen whales which were not assignable to extant whale families.
Comparing the cranial and mandibular morphology of 23 taxa (including late archaeocetes and both fossil and extant mysticetes), found Cetotheriidae in this traditional sense to be polyphyletic. Based on ten cranial characters, they also concluded that of the twelve included fossil baleen-bearing mysticetes, six formed a monophyletic group, Cetotheriidae '' sensu stricto''.
Several phylogenetic studies since Bouetel & Muizon 2006 support the monophyly of a small group of core Cetotheriidae ''sensu stricto'', archaic mysticetes with a cranium that have "a long ascending process of the maxilla with anteriorly diverging lateral border that interdigitates with the frontal" and some other characters. This group is limited to ''Cetotherium rathkii'', ''Metopocetus durinasus'', ''Mixocetus elysius'', ''Herpetocetus scaldiensis'', ''H. transatlanticus'', ''H. bramblei'', ''Nannocetus eremus'', and ''Piscobalaena nana''. The remaining genera placed in the family are considered Cetotheriidae ''
sensu lato
''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular c ...
'' and are often referred to as the 'cetotheres'.
considered the primitive 'cetothere' ''
Joumocetus
''Joumocetus'' is a genus of extinct baleen whale in the family Cetotheriidae containing the single species ''Joumocetus shimizui''. The species is known only from a partial skeleton found in Miocene age sediments of Japan.
History and classifi ...
'' the most basal named taxon of their new superfamily Thalassotherii (Cetotheriidae ''s.l.'', Cetotheriidae ''s.s.'', Eschrichtiidae (gray whales) and Balaenopteridae (rorquals)) and suggested that the term "Cetotheriidae ''s.l.''" should be renamed "basal" or "stem thalassotherians". found that the pygmy right whale formed a well-supported clade with Eschrichtiidae and Balaenopteridae based on molecular data, and that, within 'cetotheres', it was most closely related to the herpetocetines ('' Herpetocetus'' and '' Nannocetus'') Bisconti et al. 2013, however, found, based on morphological data, it to be more closely related to Balaenidae (the bowhead and right whales), but added that additional specimens are expected to resolve these conflicting results within a few years.
Classification of Cetotheriidae according to El Adli et al. (2014) and the Fossilworks online database:
* †'' Cephalotropis'' Cope 1896
* †''
Joumocetus
''Joumocetus'' is a genus of extinct baleen whale in the family Cetotheriidae containing the single species ''Joumocetus shimizui''. The species is known only from a partial skeleton found in Miocene age sediments of Japan.
History and classifi ...
''
* Subfamily: † Cetotheriinae Whitmore and Barnes, 2008
** †'' Brandtocetus'' Gol'din and Startsev 2014
** †''
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 ...
Herentalia
''Herentalia'' is a genus of cetotheriid
Cetotheriidae is a family of baleen whales (parvorder Mysticeti). The family is known to have existed from the Late Oligocene to the Early Pleistocene before going extinct. Although some phylogenetic ...