Rhynchonellata - Orthida - Plaesiomyidae
Parent taxon: Plaesiomyidae according to M. Liljeroth et al. 2017
See also Mitchell 1977, Williams et al. 2000 and Zuykov et al. 2008
Sister taxa: Bokotorthis, Evenkininae, Metorthinae
Subtaxa: Austinella Campylorthis Chaulistomella Dinorthis Madiorthis Multicostella Plaesiomys Retrorsirostra Valcourea
Ecology: stationary epifaunal suspension feeder
Distribution:
• Silurian of Sweden (6 collections)
• Ordovician to Silurian of United States (1: California)
• Ordovician of Argentina (5), Australia (19), Belarus (2), Bolivia (5), Canada (139: British Columbia, Manitoba, Northwest Territories, Nunavut, Nunvait, Ontario, Quebec), China (12), Estonia (20), France (1), Ireland (5), Kazakhstan (23), Myanmar (1), Norway (4), Peru (1), Poland (1), the Russian Federation (22), the United Kingdom (51), United States (357: Alaska, California, Colorado, Georgia, Idaho, Illinois, Illinois, Iowa, Indiana, Iowa, Kentucky, Michigan, Minnesota, Missouri, Nevada, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, Virginia, Wisconsin, Wyoming)
• Chazy of Canada (7: Ontario, Quebec), United States (51: New York, Tennessee, Virginia)
• Llandeilo of China (1), the United Kingdom (2), United States (1: Tennessee)
• Whiterockian of United States (12: Nevada)
• Arenig of Bolivia (3), Canada (1: New Brunswick), China (2)
Total: 755 collections including 957 occurrences