A new species of the arthrodire genus Groenlandaspis is described from the upper part of the Evieux Formation (Upper Famennian), based on several specimens collected from quarries at Modave and Villers-le-Temple,Liège Province, Belgium. It is the first occurrence of this widespread genus in continental Europe. This new species is characterized by an almost smooth dermal armour, except for some scattered tubercles on its skull roof, median dorsal and spinal plates. Its median dorsal plate is triangular in shape and almost perfectly equilateral in lateral aspect and bears large, spiniform denticles on its posterior edge. All these Groenlandaspis remains occur in micaceous, dolomitic claystones or siltstones probably deposited in a subtidal environment. Outcrops of the same area have yielded other vertebrate remains, such as the placoderms Phyllolepis and Bothriolepis, acanthodians, various piscine sarcopterygians (Holoptychius, dipnoans, a rhizodontid, Megalichthys, Eusthenodon and a large tristichopterid), and a tetrapod that is probably close to Ichthyostega. The biogeographical history of the genus Groenlandaspis is briefly outlined, and the late Frasnian-Famennian interchange of vertebrate taxa between Gondwana and Euramerica is discussed. |
