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| regnum = Chromalveolata | divisio = Haptophyta | classis = Prymnesiophyceae | ordo = Coccosphaerales | familia = Coccolithaceae | genus = ''Discoaster'' | genus_authority = Tan Sin Hok, 1931 }} ''Discoaster'' is a genus of extinct star-shaped marine algae, with calcareous exoskeletons of between 5-40 μm across that are abundant as nanofossils in tropical deep-ocean deposits of Neogene age. ''Discoaster'' belongs to the haptophytes. About 100 species can be recognized.〔(【引用サイトリンク】publisher= Springer )〕 == Biostratigraphic significance == The International Commission on Stratigraphy (ICS) has assigned the extinction of ''Discoaster brouweri'' as the defining biological marker for the start of the Calabrian Stage of the Pleistocene, 1.806 million years ago. ICS has assigned the extinction of ''Discoaster pentaradiatus'' and ''Discoaster surculus'' as the defining biological marker for the start of the Gelasian Stage, 2.588 million years ago, the earliest stage of the Pleistocene. ICS further assigned the extinction of ''Discoaster kugleri'' as biological marker for the start of the Tortonian Stage of the Miocene, 11.62 million years ago. 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「Discoaster」の詳細全文を読む スポンサード リンク
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