Adynomosaurus arcanus, a new lambeosaurine dinosaur from the Late Cretaceous Ibero-Armorican Island of the European archipelago

The South Pyrenean Foredeep Basin in northeastern Spain preserves one of the best-documented paleontological records of European terrestrial vertebrates for the last few million years of the Mesozoic Era. We describe Adynomosaurus arcanus gen. et sp. nov., a lambeosaurine hadrosaurid from strata nearly four million years older than the other recognized lambeosaurine in the basin, Pararhabdodon isonensis. This species is the second hadrosaurid recovered from the South Pyrenean Foredeep Basin and the fifth in Europe. Adynomosaurus arcanus is unique among hadrosaurids in possessing a scapula with a relatively unexpanded blade. Phylogenetic analysis places this species in a polytomic relationship with other outgroup taxa to Parasaurolophini and Lambeosaurini, such as Pararhabdodon isonensis, Tsintaosaurus spinorhinus and Aralosaurus tuberiferus. The unusual reduction of the scapular blade of A. arcanus suggests decreased strength of the M. deltoideus scapularis and M. subscapularis relative to that of other hadrosaurids. (C) 2018 Elsevier Ltd. All rights reserved.