Hyolitha - Orthothecida - Gracilithecidae
Full reference: V. Sysoev. 1972. Biostratigrafiâ i hiolity ortotetsiomorfy nižnego kembriâ Sibirskoj platformy. Âkutskij filial’ Sibirskogo otdeleniâ Instituta Geologii AN SSSR, Âkutsk. 1-152
Parent taxon: Orthothecida according to J. M. Malinky and C.B. Skovsted 2004
See also Kouchinsky et al. 2011
Sister taxa: Aldanothecidae, Allathecidae, Ancheilotheca, Bolitheca, Brevitheca, Bucanotheca, Carinitheca, Chelsonella, Circothecidae, Cupitheca, Curtitheca, Ebianotheca, Eogloborilus, Eonovitatus, Girvanolithes, Grandicornus, Hexitheca, Inflaticornus, Isititheca, Khetatheca, Kotuyitheca, Lophotheca, Minitheca, Mooritheca, Neobactrotheca, Nikatheca, Novitatidae, Orthothecidae, Panitheca, Paragloborilus, Petasotheca, Plicitheca, Probactrotheca, Renitheca, Sysoievia, Tchuranitheca, Tetratheca, Tetrathecidae, Triplicatellidae, Turcutheca
Subtaxa: Gracilitheca
Type: Gracilitheca
Ecology: stationary epifaunal suspension feeder
Distribution:
• Cambrian of Canada (4: Nova Scotia collections), Greenland (3), United States (3: Massachusetts)
• Solvan of Morocco (1)
Total: 11 collections each including a single occurrence