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Tranatocetus
''Tranatocetus'' is an extinct genus of mysticete from the late Miocene (Tortonian) of Jutland, Denmark. The type and only species is ''Tranatocetus argillarius''. Description ''Tranatocetus'' is similar to ''"Aulocetus" latus'', ''"Cetotherium" megalophysum'', ''"Cetotherium" vandelli'', ''Mesocetus'', and '' Mixocetus'' in having rostral bones that override the frontals and contact the parietals, nasals dividing the maxillae on the vertex, a dorsoventrally bent occipital shield with a more horizontal anterior portion and more vertical posterior portion, and a tympanic bulla with short, narrow anterior portion with rounded or squared anterior end and wider and higher posterior portion that is particularly swollen in the posteroventral area. Like other tranatocetids, the skull vertex of ''Tranatocetus'' is X-shaped in dorsal view. However, ''Tranatocetus'' differs in having a wide skull with laterally expanded squamosals, straight ascending processes of maxillae which extend par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tranatocetus
''Tranatocetus'' is an extinct genus of mysticete from the late Miocene (Tortonian) of Jutland, Denmark. The type and only species is ''Tranatocetus argillarius''. Description ''Tranatocetus'' is similar to ''"Aulocetus" latus'', ''"Cetotherium" megalophysum'', ''"Cetotherium" vandelli'', ''Mesocetus'', and '' Mixocetus'' in having rostral bones that override the frontals and contact the parietals, nasals dividing the maxillae on the vertex, a dorsoventrally bent occipital shield with a more horizontal anterior portion and more vertical posterior portion, and a tympanic bulla with short, narrow anterior portion with rounded or squared anterior end and wider and higher posterior portion that is particularly swollen in the posteroventral area. Like other tranatocetids, the skull vertex of ''Tranatocetus'' is X-shaped in dorsal view. However, ''Tranatocetus'' differs in having a wide skull with laterally expanded squamosals, straight ascending processes of maxillae which extend par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesocetus
''Mesocetus'' is an extinct genus of baleen whale from the Miocene of Europe (Antwerp, Belgium and Balkans). Description ''Mesocetus'' is similar to other tranatocetids in having rostral bones that override the frontals and contact the parietals, nasals dividing the maxillae on the vertex, a dorsoventrally bent occipital shield with a more horizontal anterior portion and more vertical posterior portion, and a tympanic bulla with short, narrow anterior portion with rounded or squared anterior end and wider and higher posterior portion that is particularly swollen in the posteroventral area. Shared characters with ''Tranatocetus'' include posterior ends of premaxillae fused with the maxillae and divided on the vertex by long, narrow and high (vertical plate-like) nasals and cervical vertebrae with wide transverse foramina, almost as wide as the centra. Species * ''Mesocetus agrami'' Van Beneden, 1886; known from late Miocene (late Serravallian) of the Balkans. * ''Mesocetus aquitan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cetotheriidae
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 studies conducted by recovered the living pygmy right whale 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 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' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tortonian
The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian. The Tortonian roughly overlaps with the regional Pannonian Stage of the Paratethys timescale of Central Europe. It also overlaps the upper Astaracian, Vallesian and lower Turolian European land mammal ages, the upper Clarendonian and lower Hemphillian North American land mammal ages and the upper Chasicoan and lower Huayquerian South American land mammal ages. Definition The Tortonian was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1858. It was named after the Italian city of Tortona in the region Piedmont. The base of the Tortonian Stage is at the last common appearance of calcareous nanoplankton '' Discoaster kugleri'' and planktonic foram '' Globigerinoides subquadratus''. It is also associated with the short normal polarized magneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixocetus
''Mixocetus'' is a genus of extinct baleen whale belonging to the family Tranatocetidae. It is known only from the late Miocene (Tortonian) of Los Angeles County, California. Description ''Mixocetus'' is a large-size mysticete with a long, narrow rostrum, a robust braincase, a nostril opening extending posteriorly just a few inches behind the antorbital processes, the posterior ends of the premaxillae, maxillae, and nasals tapering and extending posteriorly to a point between superior parts of supraorbital processes of the frontals, and a temporal fossa opening dorsally. Unlike ''Cetotherium'', the antorbital process is larger, the lateral margins of the supraoccipital processes of the frontals are parallel to each other, there is a protruding lateral wall of the braincase, and the rear portion of the cranium has a very thick and posteriorly protruding exoccipital.M. D. Uhen, R. E. Fordyce, and L. G. Barnes. 2008. Odontoceti. In C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sister Group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and taxon B are sister groups to each other. Taxa A and B, together with any other extant or extinct descendants of their most recent common ancestor (MRCA), form a monophyletic group, the clade AB. Clade AB and taxon C are also sister groups. Taxa A, B, and C, together with all other descendants of their MRCA form the clade ABC. The whole clade ABC is itself a subtree of a larger tree which offers yet more sister group relationships, both among the leaves and among larger, more deeply rooted clades. The tree structure shown connects through its root to the rest of the universal tree of life. In cladistic standards, taxa A, B, and C may represent specimens, species, genera, or any other taxonomic units. If A and B are at the same taxonomic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metopocetus
''Metopocetus'' is an extinct genus of baleen whale belonging to the family Cetotheriidae. The type species is ''Metopocetus durinasus''. Description ''Metopocetus'' is diagnosable by lateral occipital crests continuous with temporal crests that diverge forward, as well as elongate frontals, and short nasal bones that project posterior to frontals. Location ''Metopocetus durinasus'' is known only from the middle Miocene (Langhian) Calvert Beach Member of the Calvert Formation of Westmoreland County, Virginia. Its type specimen is USNM 8518. On the other hand, ''Metopocetus hunteri'' is based on a partial cranium from the Breda Formation of the 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 ....Marx FG, Bosselaers MEJ, Louwye S. (2016) A new species of Metopocetus (C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene Cetaceans
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Cetacean Genera
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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