SERPUKHOVIAN CONODONTS FROM NORTHERN SPAIN AND THEIR BIOSTRATIGRAPHIC APPLICATION

Abstract:  Conodont collections from late Viséan–early Bashkirian deposits include numerous elements related to the cosmopolitan species Gnathodus bilineatus (Roundy) in the Cantabrian Mountains. Arnsbergian beds yield the taxa Gnathodus bilineatus leonicus subsp. nov., G. millarensis sp. nov., G. truyolsi sp. nov. and Gnathodus sp. nov. A. Almost all are also found in limestones of similar age in the Pyrenees, and the G. truyolsi conodont Zone is defined for the upper Serpukhovian of the northern Iberian Peninsula. In addition, numerous references to the proposed taxa come from Austria, Eastern Europe, Northern Africa and Asian localities. The increase in gnathodid diversity and abundance in northern Spain is related to a local Arnsbergian drowning episode of the carbonate platform. G. truyolsi is possibly derived from G. b. bilineatus , and there is morphological convergence with Gnathodus kiensis Pazukhin.