鬆卷角石

鬆卷角石（學名：）是一屬已滅絕的鸚鵡螺類。牠們生活在晚奧陶紀的海洋中。其化石分布於北美及中國。

特徵
鬆卷角石擁有捲曲的外殼，盤捲得很鬆，因而得名。其螺層間並不相連。

牠們在概述上與愛沙尼亞角石及*'相近，但其截面與Clytoceras*最為相似。

物種
*Aphetoceras americanum
*Aphetoceras attenuatum
*Aphetoceras boreale
*Aphetoceras evolutum
*Aphetoceras farnsworthi
*Aphetoceras oderi
*Aphetoceras ruedemanni
*Aphetoceras subcostulatum

參考文獻

• Aphetoceras, p K358 in Vol K of the Treatise on Invertebrate Paleontology in the section on the Estonioceratidae, p K357-K359, included in the Chapter on the Tarphycerida by Furnish and Glenister starting with page K343.

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