Devonohexapodus bocksbergensis is a synonym of Wingertshellicus backesi (Euarthropoda) – no evidence for marine hexapods living in the Devonian Hunsrück Sea

The Devonian Hunsrück Slate fossil Devonohexapodus bocksbergensis Haas, Waloszek & Hartenberger, 2003 has been interpreted as a stem-lineage representative of the Hexapoda, implying their marine origin and independent terrestrialisation within the ‘Atelocerata’. Devonohexapodus bocksbergensis was based on a single specimen embedded in a lateral position. Reinvestigation of that holotype and of all known specimens of the Hunsrück Slate arthropod Wingertshellicus backesi Briggs & Bartels, 2001 demonstrates that all this material represents a single species. The latter is redescribed, its taxonomic diagnosis is emended, and the name Devonohexapodus bocksbergensis is treated as a junior synonym of Wingertshellicus backesi. The phylogenetic position of W. backesi neither is that of a stem-lineage representative of Hexapoda, nor does it fall within the crown group Mandibulata. The Hunsrück Slate provides no evidence of an independent terrestrialisation within the ‘Atelocerata’ or of a marine origin of the Hexapoda.