Ambiortus dementjevi belongs to
Ornithuromorpha, the natural group containing modern birds but not
Enantiornithes, according to all published
cladistic analyses. The exact position of the species within this group has been controversial. Early studies suggested it was a member of
Palaeognathae, the group containing modern
ratites and
tinamou, but this has not been supported by later research. Some studies have found it to be closely related to the
Ichthyornithes, a relatively derived group closely related to
modern birds. Most analyses have found it to be either an unresolved member of the
Ornithurae, or a more basal member of Ornithuromorpha. One 2006 study, for example, found it to be more primitive than
Yanornis but more advanced than
Hongshanornis, or even a member of the specific group containing both
Yanornis and
Yixianornis. The
family Ambiortidae is sometimes used for this genus, especially if it is considered a close relative of the much younger
Apsaravis. The results of a
cladistic analysis published in 2011 indicate that at least
Apsaravis and
Palintropus, which was initially mistaken as a more modern bird genus initially, are very closely related. ==References==