to Isona. Additional material from the type locality was collected in 1994 - including two maxillae, two dorsal vertebrae, a complete sacrum, two fragmentary ribs, and a partial ischium. The species name was corrected to isonensis in 1997 by Laurent et al.. The new material, most importantly cranial and mandibular elements (those from the skull) led to Casanovas-Cladellas' team re-classifying it as a hadrosaurid as opposed to a basal iguanodont. In 1999 it was more specifically identified as a lambeosaurine hadrosaur, in a paper again by Casanovas-Cladellas et al.. This made it the first member of the subfamily from the continent, and the second valid hadrosaur, preceded by Telmatosaurus and the dubious Orthomerus. In total, known material from the type locality includes: a left and a right maxilla; five cervical, five dorsal, and one caudal vertebra; a sacrum; fragmentary rib bones; one end of the right ; a fragment of the left , an and a . All of this material was excavated from a by surface, and it is thought to have belonged to a single individual. The holotype is a nearly complete caudally located cervical vertebra (a cervical vertebra located near the base of the neck), specimen number IPS SRA-1. Another cervical, a humerus, and an ulna were designated the paratype specimens. In 2020, Jesús F. Serrano and colleagues described new hindlimb material from the site, found in 2018. These are thought to belong to the holotype individual. This includes a , a partial , a complete , and a . Referred material from other localities In their 1997 paper, Laurent and colleagues referred remains from the Le Bexen site of the uppermost Cretaceous of Aude, southern France, to the genus. Prieto-Márquez and colleagues commented on this referral in a 2006 paper, although noted they had not examined the material themselves. They concluded all the specimens, excepting one fragmentary humerus, were too poorly preserved to allow proper comparison with the holotype material. As such, they disagreed with the referral. Of the humerus, they found it distinguishable from that of the SRA material, and so also not referable to the species. First hand study for a 2013 re-evaluation of European lambeosaurine material supported these conclusions. Laurent had, in a 2003 dissertation, referred more French lambeosaurine material to Pararhabdodon, held at the Musée des Dinosaures d’Espéraza; the referral was made as the genus was at that point the only named