The Middle Jurassic stephanoceratid ammonite Kumatostephanus from Dorset and Somerset, UK, and its evolution

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• 作者：Robert Baron Ch ; ler ; John Whicher ; Wolfgang Grulke ; Andy Cowap
• 关键词：Ammonites ; Bajocian ; Dorset ; Inferior Oolite ; Kumatostephanus ; Stephanoceratids
• 刊名：Geobios
• 出版年：2013
• 出版时间：July-August, 2013
• 年：2013
• 卷：46
• 期：4
• 页码：285-297
• 全文大小：6555 K

文摘

A new exposure at Oborne, Dorset has yielded a rich fossil assemblage of the Lower Bajocian ammonite Kumatostephanus from the Laeviuscula and Humphriesianum zones. The principal bed containing this ammonite, the Green Grained White Marl is locally diachronous; it is an important local marker horizon and it is herein proposed as a formal stratigraphical unit. The specimens obtained allow a better understanding of the evolution of the genus Kumatostephanus and its relationships to the other stephanoceratids, notably Stemmatoceras.