Immognathus rhabdotus Schäfer, 1976
Sugerowana cytacja: Dzik 2015. Immognathus rhabdotus Schäfer 1976. Ikonoteka (http://ikonoteka.paleo.pan.pl/xwiki/bin/view/Species/Immognathus+rhabdotus+)
Diagnoza P1 elements with transversely ribbed platform tending to become flat dorsally in mature specimens and with parallel sides over most of its length. Porównanie In sample Ost-3 P1 elements of this species dominate among polygnathids, being associated with robust ramiform elements of the Ctenopolygnathus type that supports the generic placement of the species. Subadult P1 elements of this species are virtually homeomorphic with those of Pinacognathus? praesulcatus. The difference is best visible in juveniles, having ventrally wider platform than in P. praesulcatus and in larger elements, with basal cavity of less angular section. If the partial apparatus reconstruction of the Tournaisian Pinacognathus? sulcatus is correct, all these species may belong to the same lineage. The generic name Immognathus may then appear appropriate to them and is to be transferred to the family Elictognathidae to ensure its monophyly. From stratigraphically older Polygnathus? pennatulus the species differs in a less triangular outline of the platform and in lanceolate basal cone. The P1 elements of similar morphology from the boundary strata between the Famennian and Tournaisian, were identified by Bouckaert and Groessens (1976), Over (1992), and Sanz-López et al. (1999) as Polygnathus inornatus (with a Tournaisian type population, classified in Pinacognathus by Dzik 1997) and as Pseudopolygnathus graulichi by Austin et al. (1985). The lineage continued to the Carboniferous possibly represented there by Pinacognathus inornatus (E.R. Branson, 1934) (e.g., Dzik 1997). P. graulichi, with a very large basal cone, is rather a member of the Dasbergina lineage. Relationships and nomenclature of these latest Famennian and early Tournaisian forms requires clarification. Autekologia Występowanie geograficzne Ostrówka. Zasięg czasowy L. styriacus to D. trigonica Zones. Materiały muzealne ZPAL: 47 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. |
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