 I. lakotaensis was described by David B. <unk> and Philip R. <unk> in 1989 . The only well @-@ accepted North American species of Iguanodon , I. lakotaensis was described from a partial skull from the Barremian @-@ age Lower Cretaceous Lakota Formation of South Dakota . Its assignment has been controversial . Some researchers suggest that it was more basal than I. bernissartensis , and related to <unk> , but David Norman has suggested that it was a synonym of I. bernissartensis . Gregory S. Paul has since given the species its own genus , <unk> . 
