Tityosteus, a marine fish (Arthrodira, Homostiidae) from the Emsian of Aragón, Spain, and its distribution

A right marginal plate (over 11 cm long) of Tityosteus cf. rieversae Gross, 1960, emend., has been found in the late part of the Early Emsian (late Zlichovian) in the Mariposas Fm. of the Eastern Iberian Cordillera in southern Aragón. The palaeoecological conditions correspond to a hemipelagic ensialic basin, with predominant elements of Hercynic biofacies but still with photic bottom. The Emsian genus Tityosteus is now known from the Hunsrück Schiefer of Germany and the closely connected Ibero-Armorican Trough and also from the more distant Minusinsk Basin of southern Siberia. Palaeo-oceans between western Europe and southern Siberia were no zoogeographical barriers for these large, possibly microphagous fishes in open sea. The name of the type species of Tityosteus is emended.