Amorphognathus superbus (Rhodes, 1953) from the Mójcza Limestone.

Apparatus of Amorphognathus superbus (Rhodes, 1953).

Diagnoza

The sinistral P₁ element without any lobe on its inner process (if present in some specimens of early populations the point of branching is near the cusp). The M elements with a few robust denticles of similar length and an undenticul ated external process.

Porównanie

The boundary between A. tvaerensis and A. superbus corresponds to disappearance of the accesory lobe of the inner process of the left P₁ element. At Mójcza there is a significant zone of overlap in the occurrence of lobed and unlobed sinistral P₁ elements. In the course of evolution the point of bifurcation of the lobe was closer and closer to the cusp and finally it disappeared.
The M elements have denticulation distinct from that in the succeeding A. ordovicicus. However, they are very variable within the population, and their usefulness in the demarcation of the boundaries of the species is rather limited, especially in the case of the lower boundary. Elements identical with the holotype of A. superbus can be found well within the range of A. tvaerensis .

Autekologia

Występowanie geograficzne

Zalesie, Mójcza.

Zasięg czasowy

The transition from A. tvaerensis to A. superbus took place in the interval 2.0-2.5 m above the bentonite, the transition to A. ordovicicus is even more difficult to indicate precisely but
the dominance of the cusp over the denticles in the M elements develops somewhere within the basal parts of the marly limestones of the Zalesie Formation in the topmost parts of the section at Mójcza.

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.