It consists of the order Vetulicolata (which contains the familes Vetulicolidae and Didazoonidae)[1] and the genus Nesonektris, which is of uncertain placement.

[2] It is distinguished from the Banffozoa by the number and size of posterior segments as well as features of the anterior section.

[3] In 1997, Chen and Zhou defined Vetulicolida as a class to contain Vetulicola and Banffia.

The name Vetulicolida was used at either or both ranks until 2007, when a comprehensive phylogeny renamed the order to Vetulicolata.

[6] A 2024 analysis found Vetulicolida to be the more recent portion of a paraphyletic grade leading to more crownward chordates, with Nesonektris basal to Vetulicolata (Vetulicolidae is labeled according to a 2018 phylogeny):[7][4] Banffia† Heteromorphus† Skeemella† Nesonektris† Vetulicolidae† Didazoon† Pomatrum† Yuyuanozoon† Yunnanozoon† Cathaymyrus† Pikaia† Chordata(crown group) An earlier study in 2014 placed vetulicolians as the sister-group to tunicates, but was unable to resolve any relationships among vetulicolians as a group:[2] Vetulicola† Beidazoon† Ooedigera† Nesonektris† Pomatrum† / Xidazoon† Didazoon† Yuyuanozoon† Banffia† Heteromorphus† Tunicata