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Spiriferida is an order of extinct articulate brachiopod fossils which are known for their long hinge-line, which is often the widest part of the shell. In some genera (e.g. ''Mucrospirifer'') it is greatly elongated, giving them a wing-like appearance. They often have a deep fold down the center of the shell. The feature that gives the spiriferids their name ("spiral-bearers") is the internal support for the lophophore; this ''brachidium'', which is often preserved in fossils, is a thin ribbon of calcite that is typically coiled tightly within the shell. Spiriferids first appear in the Early Ordovician. They were rare during the Silurian but underwent a dramatic evolutionary radiation during the Devonian period, reaching peak development in variety and numbers. Spiriferida survived the great Permian extinction, finally becoming extinct during the Early Jurassic. Fossils of this order are often preserved as pyrite. ==Taxonomy== Order Spiriferida *Suborder Delthyridina * *Superfamily Delthyridoidea * * *Family Acrospiriferidae * * *Family Cyrtinopsidae * * *Family Delthyrididae * * *Family Hysterolitidae * * *Family Mucrospiriferidae * *Superfamily Reticularioidea * * *Family Elythidae * * *Family Reticulariidae * * *Family Thomasariidae * * *Family Xenomartiniidae *Suborder Spiriferidina * *Superfamily Adolfioidea * * *Family Adolfiidae * * *Family Echinospiriferidae * *Superfamily Ambocoelioidea * * *Family Ambocoeliidae * * *Family Eudoxinidae * * *Family Lazutkiniidae * * *Family Verneuiliidae * *Superfamily Brachythyridoidea * * *Family Brachythyrididae * * *Family Skelidorygmidae * *Superfamily Cyrtioidea (syn. Cyrtiacea) * * *Family Costispiriferidae * * *Family Cyrtiidae * * *Family Hedeinopsidae * *Superfamily Cyrtospiriferoidea * * *Family Conispiriferidae * * *Family Cyrtospiriferidae * * *Family Spinocyrtiidae * *Superfamily Martinioidea * * *Family Crassumbidae * * *Family Elythynidae * * *Family Gerkispiridae * * *Family Ingelarellidae * * *Family Martiniidae * * *Family Perissothyrididae * * *Family Tenellodermidae * *Superfamily Paeckelmanelloidea * * *Family Paeckelmanellidae * * *Family Strophopleuridae * *Superfamily Spiriferoidea * * *Family Choristitidae * * *Family Imbrexiidae * * *Family Reticulariacea * * *Family Spiriferellidae * * *Family Spiriferidae * * *Family Trigonotretidae * *Superfamily Theodossioidea * * *Family Palaeochoristitidae * * *Family Theodossiidae * * *Family Ulbospiriferidae 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「Spiriferida」の詳細全文を読む スポンサード リンク
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