[7] Micrina and Paterimitra possess bivalved shells in their larval phases, which preserve characters that might position them in the Linguliformea and Rhynchonelliformea stem lineages respectively.

[8] For a long part of their history, the tommotiids were only known from disarticulated shells - a complete organism had not been found.

[5][7] Articulated specimens of Paterimitra, discovered a year later, suggest a similar form and lifestyle - it is possible that many tommotiids need redescribing as sessile tube-dwellers.

[10] However, the discovery of the articulated camenellan Wufengella showed that it was a free-living worm-like animal, suggesting that it was not a crown-group lophophorate, as the last living common ancestor of all living lophophorates has been predicted to be sessile, as bryozoans, brachiopods and phoronids are.

[10] These discoveries have produced an alternative model for the origin of the brachiopods; it suggested that they evolved by the reduction of sessile tube-like organisms, until only two shells were left.