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Mitta V.V. (2011) Ammonites of Tethyan origin in the Ryazanian Stage of the Russian platform: genus Riasanella gen. nov. // Palaeontol. Journ. V. 45. No 1. P. 13-22.

A new ammonite genus Riasanella is described from the Ryazanian Stage of the Russian Platform (type species R. rausingi sp. nov.). The new species R. plana sp. nov., R. olorizi sp. nov., and R. riasanitoides sp. nov. are described. These species come from the lower, strongly condensed beds of the Riasanites rjasanensis Zone of the Moscow Region. The upper subzone of this zone in the Ryazan Region contains specimens of Riasanella, identified in open nomenclature. The new genus is assigned to the family Himalayitidae; one of its species is a possible ancestor of Riasanites Spath.



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