Elements of Drepanodus arcuatus Pander, 1856 from the Mójcza Limestone.

Diagnoza

The symmetrical S₀ element with smooth lateral surfaces, its inner margin sharp, in juveniles with smooth flanks, but in adults they may bear angulations. The M elements robust, with a deep round incision above the base. All elements hyaline.

Porównanie

During the evolution of this Drepanodus lineage elements become more and more prominently ornamented along their inner edges. In the Arenig some rare specimens (usually large ones) bear three ridges along this edge but elements with a more elaborated ornamentation, which is typical for the later D. robustus, are lacking. These transitional populations that still did not develop five ridges along the inner edge in adult elements are arbitrarily assigned to D. robustus .

Autekologia

Występowanie geograficzne

Baltic region. The Bukówka quarry and Mójcza in the Holy Cross Mts. 

Zasięg czasowy

Arenig. Limestone intercalation in the Bukówka sandstone and basal part of the Mójcza Limestone. 

Materiały muzealne

ZPAL

Literatura

Dzik, J. 1994. Conodonts of the Mójcza Limestone. In: J. Dzik, E. Olempska, & A. Pisera. Ordovician carbonate platform of the Holy Cross Mountains. Palaeontologia Polonica 53, 43-128.