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Diunatans
''Diunatans'' is an extinct genus of rorqual. It lived in the North Sea during the Early Pliocene. Two specimens have been found from the Netherlands. They were collected from the Kattendijk Formation in the province of Zeeland, which is Zanclean in age. ''Diunatans'' is considered to be a stem balaenopterid because it falls outside the ''Balaenoptera''+''Megaptera'' clade, which includes all living rorquals.
Its name means "long-distance swimmer", from the Latin ''diu'' meaning "long time" or "long distance", and ''natans'', meaning "swimming." The type species is ''D. luctoretemergo'', named after the motto of Zeeland, "Luctor et Emergo" (Latin for "I struggle and I emerge").〔
''Diunatans'' was around the size of the living minke whale. Several distinguishing characteristics can be seen in the skull of ''Diunatans'', including a large occipital condyle and very small nasal bones compared to other rorquals. The tympanic bulla, which encapsulates the middle ear, is also large.〔
''Diunatans'' is the only known fossil rorqual from the North Sea. Many other fossil rorquals have been described, but all are now considered nomina dubia. English paleontologist Richard Owen named ''Balaenoptera definata'', ''B. emarginata'', and ''B. gibbosa'' in 1844. In the late 19th century, Belgian paleontologist Pierre-Joseph van Beneden named ''B. borealina'', ''B. musculoides'', ''B. rostratella'', ''B. sibbaldina'', ''Plesiocetus goropii'', ''Megapteropsis robusta'', and ''Megaptera affinus''.〔
==References==
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Diunatans」の詳細全文を読む
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