page_title: Pararhabdodon
section_title: Classification
hierarchical_section_title: Pararhabdodon / Classification
caption_attribution_description: English: Rhabdodon priscus by Tom Parker.
context_page_description: Pararhabdodon is a genus of tsintaosaurin hadrosaurid dinosaur, from the Maastrichtian-age Upper Cretaceous Tremp Group of Spain. The first remains were discovered from the Sant Romà d’Abella fossil locality and assigned to the genus Rhabdodon, and later named as the distinct species Pararhabdodon isonensis in 1993. Known material includes assorted postcranial remains, mostly vertebrae, as well as maxillae from the skull. Specimens from other sites, including remains from France, a maxilla previously considered the distinct taxon Koutalisaurus kohlerorum, an additional maxilla from another locality, the material assigned to the genera Blasisaurus and Arenysaurus, and the extensive Basturs Poble bonebed have been considered at different times to belong to the species, but all of these assignments have more recently been questioned.
  Initially, the material was thought to belong to a rhabdodontid dinosaur, or some other similar type of primitive iguanodontian. Later discoveries of additional material revealed its true nature as a hadrosaur.
context_section_description: Pararhabdodon has been classified in a number of different positions within Iguanodontia since its remains were first discovered in the mid-1980s. When the first specimens were originally discovered and described by Casanovas-Cladellas and colleagues, they were not thought to belong a new taxon at all, but merely to belong to the genus Rhabdodon, and of an uncertain species. Not long after, they would be recognized of those of a unique species, and in 1993 they were given their modern name. At this point it was still thought to be a rhabdodontid or some other type of primitive iguanodont closely related to them. This was based on the characteristics of its vertebrae, as the cranial remains had not yet been found. In 1994 these cranial remains would be found - two maxilla - and these would be used by the original authors to establish it as a species of hadrosaur. 
  Casanovas-Cladellas et al. revised their position for a final time in 1999, when they published a paper arguing for a position as a primitive member of the hadrosaur subfamily Lambeosaurinae - this made it the first such species known from the continent of Europe. Characters of the skeleton supporting this viewpoint were the truncated and rounded anatomy of the articulation of the maxilla to the jugal, the truncated nature of the back of the maxilla itself, the ventral deflection of the front of the dentary (thought the only known dentary was later referred to a new species, Koutalisaurus, and later declared that of indeterminate lambeosaurine), its tall neural spines, and deltopectoral crest of the humerus being distally projected.
  The proposal that P. isonensis was the first known European lambeosaurine was soon challenged, however. In 2001, Jason Head, in a study re-evaluating the status of another species, Eolambia caroljonesa, as a primitive lambeosaur. Both were determined to instead be more primitive hadrosauroids more basal than the split between Lambeosaurinae and "Hadrosaurinae" (later renamed to Saurolophinae). In regards to Pararhabdodon, this was based on rebuttal of arguments put forward in the 1999 study; the present anatomy maxilla-jugal articulation was not considered a synapomorphy in Lambeosaurinae, merely the presence of this in the jugal itself, unknown in the species, and the angular deltopectoral crest is a trait present even in primitive iguanodontians. Additionally, its tooth count was lower than those of known lambeosaurs. In the 2006 re-evaluation of the genus by Albert Prieto-Márquez and colleagues, it was included in a phylogenetic analysis for the first time. This found it to be a non-hadrosaurid hadrosauroid, a similar position as had been argued by Head. The cladogram of Prieto-Márquez et al. (2006) is seen below on the left:
  Prieto-Márquez would return to the issue in 2009 along with Jonathan R. Wagner. They once again turned to the articulation between the maxilla and the jugal, finding this to link Pararhabdodon to the Asian lambeosaurine, Tsintaosaurus spinorhinus. In the 2006 phylogenetic analysis, P. isonenis had been scored as having an ancestral hadrosauroid condition for this trait, which had a strong effect on its position. Upon instead coding it for a modified version of the more advanced hadrosaurid condition, the connection between the two species to the exclusion of other lambeosaurines was supported. Multiple synapomorphies were found uniting to the two taxa, as well as identifying Pararhabdodon as a member of the subfamily as opposed to outside of Hadrosauridae. This relationship was again supported in Prieto-Márquez et al. (2013), where the  group containing the two genera was coined as the taxonomic tribe Tsintaosaurini; a diagnosis for the tribe was provided. Their cladogram is reproduced above, on the right.
caption: Modern life reconstruction of a Rhabdodon, which Pararhabdodon was originally thought to be closely related to
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