Banffia constricta

Comparison of two Burgess Shale deuterostomes, the early chordate Pikaia gracilens, and the aberrant vetulicolian Banffia constricta.

Besides its twisted or constricted tail, B. constricta differs from all other vetulicolians by having no external gill openings. Ironically, despite being known from well over several hundreds of specimens, it is still poorly studied.