 Ctenochasmatoidea was first defined by David Unwin in 2003 as the clade containing "Cycnorhamphus suevicus", "Pterodaustro guinazui", their most recent common ancestor, and all its descendants.Below is a cladogram showing the results of a phylogenetic analysis presented by Steven Vidovic and David Martill, using the earliest available definitions for each clade name.In 2018, Longrich, Martill, and Andres recovered a significantly different set of relationships for early pterodactyloids in their own analysis, as shown below using the earliest available definitions for each clade name.