Rhynchonellata - Pentamerida - Clarkellidae
Parent taxon: Porambonitoidea according to A. Williams et al. 2002
See also Zhan et al. 2010
Sister taxa: Eostrophiidae, Huenellidae, Syntrophiidae, Tetralobulidae
Subtaxa: Acanthoglypha Calliglypha Clarkella Diaphelasma Fenxiangella Parallelostrophia Stichotrophia Syntrophina Syntrophinella Yangtzeella
Type: Clarkella
Ecology: stationary epifaunal suspension feeder
Distribution:
• Dawan of China (11 collections)
• Arenig of China (27), the United Kingdom (1), United States (4: Montana, Nevada)
• Arenigian of China (10)
• Canadian of United States (1: Maryland)
• Ordovician of Canada (9: Newfoundland, Newfoundland and Labrador), China (30), Iran (1), Ireland (1), Kazakhstan (3), the Russian Federation (1), Svalbard and Jan Mayen (1), United States (31: Missouri, Montana, New York, North Dakota, Pennsylvania, Texas, Utah)
• Tremadoc of Argentina (3), China (7), the Russian Federation (2), United States (3: Montana, Utah, Vermont)
• Skullrockian of United States (4: Utah)
• Cambrian to Ordovician of the Russian Federation (1)
• Cambrian of Kazakhstan (3), United States (1: Texas)
Total: 155 collections including 171 occurrences