DescriptionMesacanthus Parexus Ischnacanthus.JPG Various primitive acanthodians from Early Devonian England and Scotland, Mesacanthus pusillus, Parexus falcatus...
image is a derivative work of the following images: File:Mesacanthus_Parexus_Ischnacanthus.JPG licensed with Cc-by-2.5, Cc-by-sa-3.0-migrated, GFDL 2008-12-28T21:10:40Z...
