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

Diagnoza

The sinistral sp 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 ne elements with a few robust denticles of similar length and an undenticul ated external process.

Porównanie

BERGSTROM(1971), supporting earlier suggestions in BERGSTROMand SWEET ( 1966) , presented the first complete reconstruction of the apparatus composition. He defined the boundary between A. tvaerensis and A. superbus at the point of disappearance of the accesory lobe of the inner process of the left sp element. In Mójcza there is a significant zone of overlap in the occurrence of
lobed and unlobed sinistral sp elements. In the course of evolution the point of bifurcation of the lobe was closer and closer to the cusp and finally it disappeared. As the lobe is very small in those specimens that possess it, and associated ne elements are of the A. superbus morphology I consider these populations to represent A. superbus .
The ne 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 .
There is a barren interval within the range of A. superbus in the Mójcza Limestone. Well preserved left sp elements have been found only in the oldest population s of the species and such a lobate specimen, not typica l for the species is included in the reconstruction of its apparatus. This prevents a biometrical study of the transition between the species and the succeeding A. ordovicicus.

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 ne elements develops somewhere within the basal parts of the marly limestones of the Zalesie Formatio n in the topmost parts of the section in Mójcza.

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.