[2] Like Banffia, Heteromorphus has a two-part body with a notable constriction between the parts, and a crossover that effectively reverses the dorsal and ventral sides between the anterior and posterior sections.

It shows Heteromorphus as part of the earliest steps, corresponding to the class Banffozoa, in the evolutionary grade leading to extant chordates.

[9] 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:[5] Vetulicola† Beidazoon† Ooedigera† Pomatrum† / Xidazoon† Didazoon† Yuyuanozoon† Banffia† Heteromorphus† Nesonektris† Tunicata H. confusus was originally described as Banffia confusa in 1997, while H. longicaudatus was described and assigned to the new genus Heteromorphus in 1999.

The discoverers of B. confusa referred to it as H. confusus in 2002, accepting its assignment to Heteromorphus and, according to a comprehensive 2007 review of vetulicolian phylogenetics, indicating that H. longicaudatus is its junior synonym.

However, the same review also noted substantial variation among Heteromorphus specimens, and that more species (including a distinct H. longicaudatus) may exist.