Eolambia [SEP] parent taxon
OMNH specimens further demonstrated that the postacetabular region of the ilium did not form a distinct process, and the articulations at the bottom of the femur are not very prominent, both of which separate "Eolambia" from more derived iguanodonts such as hadrosaurids. Thus, Head concluded that "Eolambia" was a basal member of the Hadrosauroidea, outside of the Hadrosauridae, a conclusion supported by a phylogenetic analysis finding it to be a non-hadrosaurid hadrosauroid closely related to "Probactrosaurus".
Classification Subsequent research.
In 2004, Norman
again as a non-hadrosaurid hadrosauroid, albeit as the sister group to "Protohadros". Although Head had specifically redefined the Hadrosauridae, based on shared characteristics, to include "Protohadros", Horner and colleagues adapted a taxon-based definition that excluded "Protohadros" and thus "Eolambia". They also identified additional characteristics differentiating "Eolambia" from hadrosaurids: there are coarse denticles on the teeth of the dentary, and the coronoid process is weakly expanded.
Variance in recovered phylogenetic positions for "Eolambia" persisted in