New anatomical information on Holonema (Placodermi) based on material from the Frasnian Gogo Formation and the Givetian-Frasnian Gneudna Formation, Western Australia

Additional specimens of the arthrodire Holonema westolli Miles, 1971 from the Late Devonian Gogo Formation, Canning Basin, Western Australia enables elements from the post-thoracic armour namely the vertebral column, the pelvic girdle, the pelvic fins and the squamation to be described. The species diagnosis is improved by including this new anatomical information. Comparison of H. westolli scales with isolated scales recovered from the upper beds of the Gneudna Formation permits these isolated scales to be referred to the species H. westolli. Interspecies differentiation in scale ornamentation allows the identification of Holonema species on the basis of scale morphology in the absence of body plates.