Tripodellus schleizius (Helms, 1963)  from the P. trachytera Zone at Kowala and the early Lagovignathus styriacus Zone at Ostrówka in the Holy Cross Mountains.

Tripodellus schleizius - P₁ element.

Diagnoza

Clearly separate asymmetric basal cone (pit) and sinuous blade in juvenile P₁ element, platform sometimes disappearing in front of the tip in adults with an angular posterior lobe near the cusp, triramous P₂ element.

Porównanie

The transition from T. minutus to T. schleizius can be traced through the Łagów section near the base of the C. quadrantinodosa Zone. In samples from the Lower Łagów Beds minute specimens of Tripodellus are laterally arched and their basal cone remains very small. At the base of the Upper Łagów Beds sigmoidally bent juvenile elements appear with a wide asymmetric basal cone. From some reason in these transitional samples there is a distinct bimodality in size frequency distribution and no intermediate specimens have been found. It looks as if sinuous morphologies had a higher rate of juvenile mortality, perhaps related to metamorphosis at the end of the sinuosa larva stage. The blade is usually more sinuous in adults than it was in older samples but they do not show clear separation of the larval basal cavity. Either it was resorbed, specimens with asymmetry rarely survived to adult stages, or species of two separate lineages co-occurred. The latter possibility seems unlikely, as in samples from somewhat higher beds (e.g., Ł-40) intermediate specimens occur showing continuity between extreme stages of ontogeny. This is the case also with late Famennian samples with T. gracilis. They show, however, increased juvenile mortality and are in this respect different from co-occurring conodont species. Perhaps this was an ecologically opportunistic species. In the course of evolution of the lineage within the mid Famennian the basal cavity became wider and wider, as documented in the Kowala section.

The boundary between this chronospecies and its successor T. gracilis is difficult to define as the diagnostic characters are very variable in populations and seem to spread gradually in the course of evolution. The type population of T. schleizius is uncomfortably close to the end of its range.

Autekologia

Występowanie geograficzne

Łagów, Jabłonna, Miedzianka, Kowala, and Ostrówka.

Zasięg czasowy

C. quadrantinodosa to P. trachytera Zones.  

Materiały muzealne

ZPAL: 5,112 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.