Diagnoza

The sp elements with three rows of tub ercles connected by a wide sheet with transverse wrinkles . The oz elements with an external process merging at almost right angle the
internal one.

Porównanie

The apparatus of Pygodus was interpreted by BERGSTROM ( 1971) and its evolution discussed by BERGSTROM (1983). Along with two well known element types the apparatus of Pygodus consists also of several minute ramiform elements that form a symmetry transition series (MCCRACKEN 1991 ). Of special interest is the morphology of the symmetrical element, which has its medial process weakly denticulated but split into two parallel ridges. All of the few ramiform elements
in my collection, as well as those illustrated by other authors , have at least three processes, which
may make a distinction from other prioniodontids among which at least the hi element is biramous.In a sample from the Lesieniec I borehole, located in the Polish part of the East European Platform, two oistodontiform elements have been found which, being unlikely to belong to any other conodont species, seem to represent the ne elements of Pygodus . If this identification is correct it would support a derivation of Pygodus from the prioniodontids (DZIK 1983) rather than from Polonodus (BERGSTROM 1983) unless the latter genus is also a prioniodontid as proposed by LOFGREN ( 1990).

Autekologia

Występowanie geograficzne

Mójcza

Zasięg czasowy

In Mójcza the species occurs from 0.5 m above the discontinuity to 1.5 m below
the bentonite. An interesting reversal in the course of evolution seems to have taken place within the range of P. serra. The lineage seems to evolve towards more and more narrow posterior area between the two posterior rows of tubercles. Beginning from the sample MA-57 this area again becomes wider,
thus making room for the fourth row of tubercles diagnostic for the succeeding species . Such a morphotype, transitional morphologically to P. anserinus but cooccurring with typical elements of P.serra , has been identified as a separate species by MCCRACKEN (1991).

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.