Walliserodus costatus Dzik, 1976 of the Mójcza Limestone

Diagnoza

All the elements of the apparatus with relat vely shallow basal cavities (and consequently robust cusps). Longitudinal keels are very low and generally more numerous than in other species of the genus. In the symmetry transition series an almost symmetrical element type with convex external side.

Porównanie

The species differs from W. ethingtoni in a shallower basal cavity and less prominent longitudinal ribbing, from W. nakholmensis in convex external side of (almost) symmetrical elements.
The two large element types (ne- hi) are of a Scalpellodus type and this, together with weak and numerous longitudinal keels in the remaining elements, suggests a close relationship or even derivation from the species Scalpellodus latus (VANWAMEL, 1974). The end member of the symmetry transition series may be symmetrical but this remains unclear, as the only strictly symmetrical elements found (in sample MA-I27) are of very small size. Their apparent symmetry may be due to the incomplete
development of the keels. Morphologically the closest elements from other samples (mainly from MA-128) are slightly asymmetric.

Autekologia

Występowanie geograficzne

The species appears at the base of the Mójcza limestone and occurs up to the
discontinuity surface (L. variabilis Zone, Kundan), known also in the latest Latorpian and Volkhovian of the Baltic region.

Zasięg czasowy

Materiały muzealne

Literatura

Dzik, J. 1994a 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.