| 翻訳と辞書 |
Andiva
''Andiva ivantsovi'' is a Vendian fossil, presumed to be a bilaterian triploblastic animal, known from the Winter Coast, White Sea, Russia. It was first discovered in 1977, and described as a new species in a new genus by Mikhail Fedonkin only in 2002. It lived about 555 million years ago. Fossils of ''Andiva'' also occur in South Australia.〔 All known fossils of ''Andiva'' are external molds.
==Description==
''Andiva'' was between long and from wide, with a bilaterally symmetrical shape, larger on the anterior end and narrower at the posterior. The anterior part features a smooth "fringe" followed by a surface "covered by fine ribs and sutura",〔 also described as a "quilt" with narrow, tightly packed chambers〔 The symmetry of these ribs is a glide symmetry, that is, in which the corresponding segments on the left and right sides do not line up, but are staggered. This is a feature shared by other forms belonging to the proposed taxon Proarticulata.
The original reconstruction by Fedonkin proposed that the ridged surface was a convex, thin carapace made of a chitin-like, non mineralized substance, protecting the animal while "creeping or gliding" over the sea bed. In the same reconstruction, the smooth zone was considered an imprint of the soft tissue beneath the dorsal carapace.〔
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「Andiva」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|