Obruchevacanthus ireneae gen. et sp nov., a new ischnacanthiform (Acanthodii) from the Lower Devonian of Spain

New disarticulated material of typically ischnacanthid scales, tooth whorls, and ?dentigerous jaw bones that occur recurrently together at many levels of the Lower Devonian of the Iberian Chain (Spain) is described. Based on their stratigraphical occurrence, histological evidence and comparison with similar ischnacanthid assemblages from other localities, we suggest including all of these remains in a unique natural assemblage, Obruchevacanthus ireneae gen. et sp. nov. This new taxon shares some features with Trundlelepis cervicostulata from the Lower Devonian of New South Wales (Australia), as for example the presence of a poorly developed pore-canal system in their scales. This feature suggests close phylogenetic relationship between the two taxa, supporting their assignment to the family Poracanthodidae. However, as this porecanal system is only present in a few percents of the total scales and it is very poorly developed in both Obruchevacanthus ireneae gen. et sp. nov. and Trundlelepis cervicostulata, they could represent a derived group of poracanthodids. These new data provided here increase our knowledge of the taxonomic diversity and evolution of the order Ischnacanthiformes, being so far the only ischnacanthid present at the studied area.