Helcionelloida - Helcionellida - 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: Yochelcionelloidea according to P. Bouchet et al. 2005
See also Missarzhevsky 1989, Parkhaev 2002, Parkhaev 2004 and Runnegar and Jell 1980
Sister taxa: Rugaeconidae, Trenellidae, Yochelcionellidae
Subtaxa: Acanthotheca Eurekapegma Mellopegma Planutenia Pseudoscenella Stenotheca Stenothecinae Watsonellinae
Ecology: stationary epifaunal suspension feeder
Distribution:
• Cressagian of South Korea (1 collection)
• Solvan of Australia (1)
• Placentian of United States (2: Massachusetts)
• Cambrian of Antarctica (1), Australia (24), Canada (6: British Columbia, Newfoundland and Labrador, Nova Scotia, Quebec), China (13), Germany (1), Greenland (3), New Zealand (1), Norway (1), the Russian Federation (11), the United Kingdom (2), United States (6: Idaho/ Utah, Massachusetts, New York, Pennsylvania, Utah)
Total: 73 collections including 82 occurrences