As the lower part of the Razvedochnyj Fm is of Pragian age (Matukhin 1995), the age of the arthrodire can provisionally be considered as Pragian.
Another aspect is also significant: the sclerotic plates may be either thin as probably in Eukaia, also in the large and specific arthrodire Carolowilhelmina (Mark-Kurik & Carls 2002, fig.
Classifying the arthrodire Eukaia is difficult as only the skull roof of the fish has been found.
Interestingly, Eukaia with its probable early Pragian age seems to indicate a distant relationship with arthrodire genera from quite different regions and fish assemblages.
A new actinolepid arthrodire from the Lower Devonian of Arctic Canada.
A new actinolepid arthrodire (Class Placodermi) from the Lower Devonian Sevy Dolomite, East-Central Nevada.
A long-snouted Late Eifelian arthrodire from Aragon (Spain).
An actinolepid arthrodire from the Lower Devonian of Peel Sound Formation, Prince of Wales Island.
These are represented by species of arthrodires Coccosteus, Watsonosteus and Plourdosteus and antiarchs Asterolepis and Bothriolepis.
Noteworthy is the absence of the characteristic Middle Devonian arthrodires Homostius and Heterostius (Mark-Kurik & Nemliher 2003).
Kartalaspis and other Early Devonian arthrodires and their stratigraphical significance.