Reclassification of vertebrate trackways from the Permian of Scotland and related forms from Arizona and Germany

The large number of ichnospecies in Permian vertebrate ichnology literature is often a result of a failure to recognize substrate or gait-controlled variations in trackway morphology. Additionally, regional studies were often performed in isolation from studies in other areas. Nomenclatural priority applies to the names first assigned to trackways from the Corncockle and Locharbriggs Sandstone Formations (Permian) of Dumfries and Galloway, Scotland. Only one ichnogenus, Chelichnus, and four ichnospecies are recognized here and all had been identified in the studies of Jardine in 1850 and 1853. Chelichnus represents tetrapod trackways with rounded manus and pes impressions, subequal in size with up to 5 short digits where preservation is complete. The normal trackway pattern shows a pes pace angulation of up to 90° with the manus and pes being impressed close together or possibly with a slight overlap of the manus by the pes. Chelichnus bucklandi shows a pes size of 10 to 25 mm, C. duncani shows a pes size of 25 to 75 mm, C. gigas shows a pes size of 75 to 125 mm, and C. titan displays a pes size exceeding 125 mm in length. This restriction to four ichnospecies is more in accord with the low faunal diversity to be expected from an eolian environment of Late Permian age than was the former taxonomic classification. The Permian ichnofaunas of the Coconino Sandstone of Arizona and the Cornberger Sandstein of Germany are also composed largely of these four ichnospecies.