File:Acanthodes BW.jpg

Summary
Acanthodes bronni, an acanthodian from the Early Permian of Germany, pencil drawing

Ref : Janvier, P. (2001). “Ostracoderms and the shaping of gnathostome characters”, Ahlberg, P.E. Major Events in Early Vertebrate Evolution: Palaeontology, Phylogeny, Genetics and Development, 175. CRC Press. Retrieved on 2009-01-11.