C. canadensis was described in 1881 from material found in Miguasha, Canada that dated back to the middle Frasnian stage of the Late Devonian. Two species, C. gracilis and C. gaugeri, have been found from Germany and Belarus in deposits that are of Givetian age. They were first described in 1973 from scale material that is now of questionable validity.
C. canadensis was first identified in 1881 from ancient materials in Miguasha, Canada, belonging to the middle Frasnian stage of the Late Devonian period. Subsequent discoveries of C. gracilis and C. gaugeri in Germany and Belarus, dated to Givetian age, were initially described in 1973 from uncertain scale samples.