Hyolitha - Orthothecida - Tetrathecidae
Parent taxon: Orthothecida according to P. D. Kruse 2002
Sister taxa: Aldanothecidae, Allathecidae, Ancheilotheca, Bolitheca, Brevitheca, Bucanotheca, Carinitheca, Chelsonella, Circothecidae, Cupitheca, Curtitheca, Ebianotheca, Eogloborilus, Eonovitatus, Girvanolithes, Gracilithecidae, Grandicornus, Hexitheca, Inflaticornus, Isititheca, Khetatheca, Kotuyitheca, Lophotheca, Minitheca, Mooritheca, Neobactrotheca, Nikatheca, Novitatidae, Orthothecidae, Panitheca, Paragloborilus, Petasotheca, Plicitheca, Probactrotheca, Renitheca, Sysoievia, Tchuranitheca, Tetratheca, Triplicatellidae, Turcutheca
Subtaxa: Holmitheca
Ecology: stationary epifaunal suspension feeder
Distribution:
• Cambrian of Canada (2: Newfoundland and Labrador collections)
• Templetonian of Australia (1)
Total: 3 collections each including a single occurrence