文章基本信息

标题：First nearly complete skeleton of the Cretaceous duvaliid belemnite Conobelus
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作者：Alexander Lukeneder
期刊名称：Acta geologica Polonica
印刷版ISSN：0001-5709
出版年度：2005
卷号：55
期号：2
页码：147-162
语种：English
出版社：Institute of Geology, University of Warsaw
摘要：The first Cretaceous belemnite preserved with the rostrum, slightly compressed phragmocone and part of the proostracum is described from the Early Cretaceous (Late Valanginian) Rossfeld Formation (Eibeck, Reichraming Nappe of the Northern Calcareous Alps). The rostrum has dorsal groove (alveolar furrow) typical of duvaliids, and its conical shape (round in transverse section outline), and the rounded apex allow its attribution to Conobelus STOLLEY, 1919. The new species C. pseudoheres sp. nov. is proposed based on the unique features of the specimen, i.e. persistently parallel lateral sides throughout the rostrum and the conical, blunt outline at the apex. The ration between rostrum and phragmocone is 0.78; the distances between the calcitic septa of the anterior end of the phragmocone range from 3 to 5 mm. The proostracum is 0.02 mm thick. The apical angle is 32° and the alveolar angle (posterior end of the phragmocone) is 24°. The alveolus is 40 mm long, yielding a ratio between rostrum and alveolus of 1.86. The depositional history with its fast sedimentation along with absent/limited post-mortem transportation led to extraordinarily good preservation of the examined specimen.
关键词：Belemnites;Rostrum;Phragmocone;Proostracum;Early Cretaceous;Valanginian;Northern Calcareous Alps