McDonald et al. (2012) recover
Proa at the base of Hadrosauriformes along with
Iguanodon. In his osteology of
Hypselospinus, Norman (2015) recovered
Proa in a monophyletic Iguanodontidae as closer to the East Asian
Bolong and
Jinzhousaurus than to other European members of Iguanodontidae. Verdu
et al (2017) recovered it as part of Eurasian clade including the Asian
Xuwulong, Altirhinus, Koshisaurus and
Gongpoquansaurus. Proa was found in the most derived position as sister taxon to
Batyrosaurus. ==References==