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''Charniodiscus'' is an Ediacaran fossil that in life was probably a stationary filter feeder that lived anchored to a sandy sea bed. The organism had a holdfast, stalk and frond. The holdfast was bulbous shaped, and the stalk was flexible. The frond was segmented and had a pointed tip. There were two growth forms: one with a short stem and fat frond, and another with a long stalk, elevating a smaller frond about above the holdfast. While the organism superficially resembles the sea pens (cnidaria), it is probably not a crown-group animal. ''Charniodiscus'' was first found in Charnwood Forest in England, and named by Trevor D. Ford in 1958. The name is derived from the fact that Ford only described a holdfast consisting of a double concentic circle, his species being named ''Charniodiscus concentricus''. Later it was discovered that a frond (''Charnia masoni'') was part of a closely related organism. ''Charnia'' differs in the branching structure in the frond. ''Charniodiscus'' specimens are known from across the globe dating to around . Species are distinguished by the number of segments, whether or not there is a distal spine, and the shape ratio. ==See also== List of Ediacaran genera ==References== *Glaessner, M. F., and Daily, B. (1959) ("The Geology and Late Precambrian Fauna of the Ediacara Fossil Reserve" ). ''Records of the South Australian Museum'' 13: 369-407 retrieved 26 January 2008 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「Charniodiscus」の詳細全文を読む スポンサード リンク
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