Helcionelloida - Stenothecidae
Synonym: Mellopegmidae Missarzhevsky 1989
Full reference: B. Runnegar and P.A. Jell. 1980. Australian Middle Cambrian molluscs: correction and additions. Alcheringa 4(1/2):111-113
Parent taxon: Helcionelloida according to J. O. R. Ebbestad et al. 2024
See also Bouchet et al. 2005, Missarzhevsky 1989, Parkhaev 2002, Parkhaev 2004 and Runnegar and Jell 1980
Sister taxa: Beshtashella, Ceratoconidae, Emargimantus, Helcionellida, Helcionellidae, Helcionelliformes, Michniakia, Pelagiellida
Subtaxa: Acanthotheca Eurekapegma Mellopegma Planutenia Pseudoscenella Stenotheca Stenothecinae Watsonella Watsonellinae
Type: Stenotheca
Ecology: stationary epifaunal suspension feeder
Distribution:
• Cressagian of South Korea (1 collection)
• Cambrian of Antarctica (1), Australia (26), Canada (26: British Columbia, Newfoundland and Labrador, Nova Scotia, Quebec), China (49), France (3), Germany (1), Greenland (3), New Zealand (1), Norway (1), the Russian Federation (21), Saint Pierre and Miquelon (1), Sweden (2), the United Kingdom (2), United States (8: Idaho/ Utah, Massachusetts, Nevada, New York, Pennsylvania, Utah)
• Ordian of Australia (1)
• Placentian of United States (3: Massachusetts)
Total: 150 collections including 167 occurrences