Diagnoza

The oz elements with a bifurcated inner process, sp elements with a small, usually denticulated posterior process, ne elements with sharp, strongly inclined cusp.

Synonims:

Holodontus superbus RHODES; BEDNARCZYK, 1971; Ligonodina delicata (BRANSON et Mall ); BEDNARCZYK, 1971; Ambalodus pulcher RHODES; BEDNARCZYK, 1971; Tetraprioniodus delicatus (BRANSON et MEHL); BEDNARCZYK, 1971; Rhodesognathus elegans polonicus ssp. n.; DZIK, 1976; partirn Amorphognathus tvaerensis BERGSTROM: DZIK, 1976; Rhodesognathus elegans polonicus DZIK; DZIK, 1978.

Porównanie

The species seems to be a successor of Welsh Rhodesognathus inaequalis, from which it differs mostly in having a smaller and always undivided posterior process of the sp elements. The most wide spread species of the genus, R. elegans has, as is documented by samples from the Lesieniec bore hole , a very similar appearance of the ne and other elements of the symmetry transition series. Their close similarity to cooccurring elements of Amorphognathus is the reason for the late recognition of the apparatus composition in the genus (see BERGSTROMand SWEET 1966). R. elegans differs from R. polonicus in lacking additional processes in the sp and oz elements.
The development of the platform in the sp elements is extremely variable in the species. It is remarkable that the specimens of the species preeceding this one stratigraphically in the section show more prominent platform lobes. Specimens of typical populations of the species usually bear two or three denticles on the posterior process but sometimes the process is completely missing.This is suggestive of a very weak selection pre ssure controlling the morphology of the platform elements. Probably this resulted in the evolutionary reduction of the platform in the lineage. Also the morphology of the ne elements is variable. Usually they lack an inner- posterior crest but sometimes
a rudimentary rib occurs there, which makes it difficult to di stinguish the se element s from homologous
element of A. tvaerensis.

Autekologia

Występowanie geograficzne

Mójcza, Holy Cross Mountains, Poland.

Zasięg czasowy

In Mójcza the species occurs from 1.8 to 2.4 m above the bentonite (A. tvaerensis!
superbus transition zone).

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.