 For example, the feet of one species, named "Macrophalangia canadensis", were known from the same region from which "Chirostenotes pergracilis" was recovered, but the discovery of a new specimen with both hands and feet preserved provided the support to combine them, while the later discovery of a partial skull with hands and feet suggested that "Chirostenotes" and "Caenagnathus" were the same animal, and current studies of caenagnathid relationships continue to find them as closely related genera.Longrich and colleagues (2013) defined a subgroup of Caenagnathidae, the Caenagnathinae, as all caenagnathids more closely related to "Caenagnathus collinsi" than to "Caenagnathasia martinsoni" or "Elmisaurus rarus".In 2015, the group Elmisaurinae was defined, including all species more closely related to "Elmisaurus rarus" than to "Caenagnathus collinsi".