While initially considered a member of the family
Opisthodactylidae, further examination of the fossil remains showed that it was more similar to the modern
rhea. According to
Gerald Mayr,
Diogenornis is best considered a stem-group member of the
Rheidae. However, recent phylogenetic studies have shown a closer affiliation to Australian ratites, the
cassowaries and
emus. This may reevaluate the origins and distribution of this clade, expanding their range to the South American Paleocene, well before the appearance of
Emuarius. Recent findings nonetheless show that it co-existed with early rheas, meaning the ratite diversity of South America was very high during the
Paleogene.
Diogenornis possesses a rather narrow beak, similar to that of
tinamous,
lithornithids and
cassowaries, as well as rather large wings. These traits, both rather unspecialised, seem to suggest a then recent development from a flying ancestor. == References ==