Acutimitoceras prorsum (Schmidt, 1925) from the Protognathodus kockeli horizon at Kowala in the Holy Cross Mountains.

Latest Famennian  ammonoids and a possible bellerophontid gastropod - Acutimitoceras prorsum ( H. Schmidt, 1925) from the tuffite layer (A) and laminated limestone (B) in the Kowala trench.

Acutimitoceras prorsum;  growth lines and outline of the shell.

Diagnoza

Conch aperture with radially running lateral margins and gentle ventral sinus; rounded conch venter with no signs of angulation.

Porównanie

The Kowala specimens seem to differ slightly from those from the type locality in having a less prominent ventral sinus of the aperture and more regular distribution of growth lines. The distinct growth lines are not so apparent in the German material but this may be due to exfoliation of the conch surface. The species does not fit the diagnostic character of the genus in respect to the conch form but the shape of aperture resembles that in the type species and this supports its ancestral position within the lineage.

Autekologia

Występowanie geograficzne

Kowala.

Zasięg czasowy

P. kockeli horizon.

Materiały muzealne

ZPAL: Numerous crushed and fragmentary specimens covering slabs of tuffite.

Literatura

Dzik, J. 1997. Emergence and succession of Carboniferous conodont and ammonoid communities in the Polish part of the Variscan sea. Acta Palaeontologica Polonica 42, 57-170.

Dzik, J. 2006. The Famennian "Golden Age" of conodonts and ammonoids in the Polish part of the Variscan sea. Palaeontologia Polonica 63, 1-359.