Diagnoza

The evolutionary position of this species has been discussed by Belka (1983) andBiner et al. (1986). According to them, this is the last member of the lineage, in which the tip of the parapet gradually develops denticulation. The Czerna specimens usually have two or three denticles. Pumell (1992) identified oz elements in M. beckmanni Bischoff, 1957. Similar, although not so robust, elements occur in Czerna being associated with symmetry transition series elements of generalised  morphology. They may belong to Mestognathus, too.

The only published evidence on Namurian conodonts is that by Vaiidek (1982) on the Gaebler marine horizon in the Czech part of the Upper Silesian Basin. Judging from identified and illustrated elements from relatively well balanced samples, the conodont fauna is represented by numerous Gnathodus bilineatus (Roundy, 1926), much less common Lochriea nodosa (Bischoff, 1957) with elements lacking tubercles at the base or with only one tubercle equally numerous as those with several tubercles, uncommon Prioniodina sp., and rare Cavusgnathus naviculus (Hinde, 190). This is the typical association known also from coeval strata in western Europe and in the Lublin area (Skompski 1996), of low diversity and with species showing relatively slow evolutionary rates. The dating of late Vis6an to earliest Westphalian strata in Poland relies mostly on ammonoids but Skompski (1996) has reported the presence of Gnathodus bollandensis, diagnostic of its own zone of early Namurian (Arnsbergian) age, in the Lublin area. In the late Namurian he has identified there an assemblage with ldiognathodus, Idiognathoides, Neognathodus, Declinognathus, and rare Adetognathus. The last marine horizon with Dunbarella contains conodonts indicative of the ldiognathoides tuberculatus Zone, of latest Westphalian A age.

Porównanie

Autekologia

Występowanie geograficzne

Zasięg czasowy

Materiały muzealne

Literatura

Dzik, J. 1997. Emergence and succession of Carboniferous conodont and ammonoid communities in the Polish part of the Variscan sea. Acta Palaeontologica Polonica 42, 57-170.