TheBashkirian, the oldest age of thePennsylvanian (also known as Upper Carboniferous), contains six biozones based on conodont index fossils, two of which are named afterDeclinognathodus species:
the zone ofDeclinognathodus marginodosus,
the zone ofDeclinognathodus noduliferus.
TheGSSP point is atArrow Canyon, Nevada, USA, with the first appearance ofDeclinognathodus noduliferus sensu lato.
The base of theMoscovian, the second stage in the Pennsylvanian, is close to the first appearances of the conodontsDeclinognathodus donetzianus Nemirovskaya, 1990 andDiplognathodus ellesmerensis Bender, 1980. The Moscovian can biostratigraphically be divided into five conodont biozones, one of which is named after aDeclinognathodus species : the zone ofDeclinognathodus donetzianus. TheGSSP candidate sections are theUral Mountains or inNaqing (Nashui), Luodian County, Guizhou, China.
^New Pennsylvanian Platform Conodonts from Southwestern United States. D. L. Dunn, Journal of Paleontology, Vol. 40, No. 6 (Nov., 1966), pages 1294-1303 (Stable URL)
Early evolution of Declinognathodus close to the Mid-Carboniferous Boundary interval in the Barcaliente type section (Spain). Javier Sanz-López and Silvia Blanco-Ferrera, Palaeontology, September 2013, Volume 56, Issue 5, pages 927–946,doi:10.1111/pala.12025
Conodont chronostratigraphical resolution and Declinognathodus evolution close to the Mid-Carboniferous Boundary in the Barcaliente Formation type section, NW Spain. Javier Sanz-López, Silvia Blanco-Ferrera and Luis C. Sánchez de Posada, Lethaia, October 2013, Volume 46, Issue 4, pages 438–453,doi:10.1111/let.12021
