- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
A spiral brachidium has been discovered in the lower Jurassic brachiopod Cadomella, which is generally regarded as the last representative of the Chonetidina. Cadomella is transferred to the Koninckinidae, which are considered to be spire-bearing Chonetidina rather than aberrant Spiriferida. The interpretation implies another independent evolution of spiralia within the Brachiopoda.