Alternognathus pseudostrigosus (Dreesen & Dusar, 1974)  from the K. crepida Zone at Kadzielnia  in the Holy Cross Mountains.

Diagnoza

Irregular, strongly asymmetric incipient platform located high on the blade slightly below the tips of its denticles in mature P₁ elements; elements of the apparatus robust of Pandorinellina type.

Porównanie

This is the earliest of the more or less certain members of the Alternognathus lineage. In its stratigraphic occurrence it significantly predates other species of Alternognathus and species of Pseudopolygnathus with robust icrion. The structure referred to as an incipient platform may approach icrion in some elements and is so irregularly developed that it is hard to say whether axial symmetry is already developed in P₁ elements of this species, or not. There seems to be an evolutionary change in the Holy Cross Mountains material; the stratigraphically younger specimens show a better developed platform originating earlier in the ontogeny and not so high on the blade. The elements are also less robust and somewhat ‘arthritic’ in appearance.

Autekologia

Występowanie geograficzne

Kadzielnia and Miedzianka(Md-2).

Zasięg czasowy

The late K. crepida Zone and the C. quadrantinodosa Zone. 

Materiały muzealne

ZPAL: 114 specimens.

Literatura

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