Iguanodont

The iguanodonts are members of the proposed group (superfamily) Iguanodontia. This is a group of ornithopod families which some palaeontologists think are closely related:
That is all the ornithopods except for the small, fast-running "Hypsilophodon". This is placed in the family Hypsilophodontidae. However, the important reference work "Vertebrate Paleontology" is not yet in support of this trend, and lists the families separately as Ornithopods. The proposal is therefore still under discussion.