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From Problem Taxa to Problem Solver: A New Miocene Family, Tranatocetidae, Brings Perspective on Baleen Whale Evolution.

Gol'din P, Steeman ME - PLoS ONE (2015)

Bottom Line: It was found to represent not only a new genus, Tranatocetus gen. nov., but also a new family; Tranatocetidae.Inclusion of problematic taxa like Tranatocetus argillarius in phylogenies brings new understanding of the distribution and diagnostic value of character traits.This underlines the need for re-examination of earlier described specimens in the light of the wealth of new information published in later years.

View Article: PubMed Central - PubMed

Affiliation: Department of Natural History and Palaeontology, The Museum of Southern Jutland, Lergravsvej 2, 6510, Gram, Denmark.

ABSTRACT
Miocene baleen whales were highly diverse and included tens of genera. However, their taxonomy and phylogeny, as well as relationships with living whales, are still a subject of controversy. Here, "Mesocetus" argillarius, a poorly known specimen from Denmark, is redescribed with a focus on the cranial anatomy. It was found to represent not only a new genus, Tranatocetus gen. nov., but also a new family; Tranatocetidae. The whales of this family have the rostral bones either overriding or dividing the frontals; the rostral bones are contacting the parietals and nasals dividing the maxillae on the vertex; the occipital shield is dorsoventrally bent. The tympanic bulla is particularly characteristic of this family featuring a short, narrow anterior portion with a rounded or squared anterior end and a wider and higher posterior portion that is swollen in the posteroventral area. A phylogenetic analysis including 51 taxa supports a monophyletic group comprising most Neogene and modern whales, with Tranatocetidae being possibly closer related to Balaenopteridae (rorquals) than to Cetotheriidae. Tranatocetidae exhibit a charahteristic bulla shape. In fact, all Neogene and modern mysticete families examined have a unique shape of the tympanic bulla that is diagnostic at family-level. Inclusion of problematic taxa like Tranatocetus argillarius in phylogenies brings new understanding of the distribution and diagnostic value of character traits. This underlines the need for re-examination of earlier described specimens in the light of the wealth of new information published in later years.

No MeSH data available.


Related in: MedlinePlus

Mandible of Tranatocetus argillarius.MGUH VP 2319: A, dorsal view. B, lateral view. C, medial view. D, posterior view. MGUH VP 2320: F, the cross-section of the anterior portion.
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pone.0135500.g008: Mandible of Tranatocetus argillarius.MGUH VP 2319: A, dorsal view. B, lateral view. C, medial view. D, posterior view. MGUH VP 2320: F, the cross-section of the anterior portion.

Mentions: The mandible is plesiomorphic in having a high mandibular foramen and opening for the mandibular canal, a wide and low condyle, and the dorsal border gradually ascending from the condyle to the coronoid process. The mandibular canal preserved in MGUH VP 2320 strongly narrows anteriorly (Fig 8). For detailed description, see [12]. The preserved portion of the hyoid apparatus comprises the basihyal and the thyrohyals, all of which are dorsoventrally flattened (Fig 9A).


From Problem Taxa to Problem Solver: A New Miocene Family, Tranatocetidae, Brings Perspective on Baleen Whale Evolution.

Gol'din P, Steeman ME - PLoS ONE (2015)

Mandible of Tranatocetus argillarius.MGUH VP 2319: A, dorsal view. B, lateral view. C, medial view. D, posterior view. MGUH VP 2320: F, the cross-section of the anterior portion.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4558012&req=5

pone.0135500.g008: Mandible of Tranatocetus argillarius.MGUH VP 2319: A, dorsal view. B, lateral view. C, medial view. D, posterior view. MGUH VP 2320: F, the cross-section of the anterior portion.
Mentions: The mandible is plesiomorphic in having a high mandibular foramen and opening for the mandibular canal, a wide and low condyle, and the dorsal border gradually ascending from the condyle to the coronoid process. The mandibular canal preserved in MGUH VP 2320 strongly narrows anteriorly (Fig 8). For detailed description, see [12]. The preserved portion of the hyoid apparatus comprises the basihyal and the thyrohyals, all of which are dorsoventrally flattened (Fig 9A).

Bottom Line: It was found to represent not only a new genus, Tranatocetus gen. nov., but also a new family; Tranatocetidae.Inclusion of problematic taxa like Tranatocetus argillarius in phylogenies brings new understanding of the distribution and diagnostic value of character traits.This underlines the need for re-examination of earlier described specimens in the light of the wealth of new information published in later years.

View Article: PubMed Central - PubMed

Affiliation: Department of Natural History and Palaeontology, The Museum of Southern Jutland, Lergravsvej 2, 6510, Gram, Denmark.

ABSTRACT
Miocene baleen whales were highly diverse and included tens of genera. However, their taxonomy and phylogeny, as well as relationships with living whales, are still a subject of controversy. Here, "Mesocetus" argillarius, a poorly known specimen from Denmark, is redescribed with a focus on the cranial anatomy. It was found to represent not only a new genus, Tranatocetus gen. nov., but also a new family; Tranatocetidae. The whales of this family have the rostral bones either overriding or dividing the frontals; the rostral bones are contacting the parietals and nasals dividing the maxillae on the vertex; the occipital shield is dorsoventrally bent. The tympanic bulla is particularly characteristic of this family featuring a short, narrow anterior portion with a rounded or squared anterior end and a wider and higher posterior portion that is swollen in the posteroventral area. A phylogenetic analysis including 51 taxa supports a monophyletic group comprising most Neogene and modern whales, with Tranatocetidae being possibly closer related to Balaenopteridae (rorquals) than to Cetotheriidae. Tranatocetidae exhibit a charahteristic bulla shape. In fact, all Neogene and modern mysticete families examined have a unique shape of the tympanic bulla that is diagnostic at family-level. Inclusion of problematic taxa like Tranatocetus argillarius in phylogenies brings new understanding of the distribution and diagnostic value of character traits. This underlines the need for re-examination of earlier described specimens in the light of the wealth of new information published in later years.

No MeSH data available.


Related in: MedlinePlus