 I. <unk> ( also spelled I. <unk> ) , described by Lydekker in 1889 has variously been considered a synonym of Hypselospinus fittoni or a distinct species assigned to the genus <unk> . A specimen from the Valanginian Wadhurst Clay Formation , variously assigned to I. <unk> and I. mantelli over the years , has an unusual combination of hadrosaurid @-@ like lower jaw and very robust <unk> ; Norman ( 2010 ) assigned this specimen to the species Hypselospinus fittoni , while Paul ( 2012 ) made it the holotype of a separate species <unk> <unk> . 
