Conodonta - Prioniodontida - Polyplacognathidae
Parent taxon: Prioniodontacea according to A. Mestre and S. Heredia 2013
See also Clark et al. 1981, Stouge and Bagnoli 1999, Sweet 1988 and Zhen et al. 2011
Sister taxa: Icriodontidae, Oepikodontidae, Phragmodontidae
Subtaxa: Baltoplacognathus Cahabagnathus Eoplacognathus Polonodus Polyplacognathus Yangtzeplacognathus
Ecology: nektonic carnivore
Distribution:
• Aluoja of Sweden (8 collections)
• Chazyan of United States (1: Tennessee)
• Whiterockian of United States (5: Nevada)
• Arenig of Argentina (2)
• Ordovician of Argentina (16), Canada (5: British Columbia, Newfoundland, Northwest Territories), China (7), Estonia (2), Kazakhstan (3), Lithuania (1), the Russian Federation (12), Sweden (3), United States (13: Iowa, Minnesota, Missouri, New York, Oklahoma)
Total: 78 collections including 92 occurrences