The systematic problem of tetrapod ichnotaxa: the case study of Pteraichnus Stokes, 1957 (Pterosauria, Pterodactyloidea)

Abstract

AbstractThis paper deals with the systematics of tetrapod ichnotaxa based on footprints. Beyond the consideration of the nomenclatural rules for ichnotaxa in the ICZN, this paper tries to determine how to establish an ichnotaxonomy that reflects the identity of the track-maker (the organism that has made the track) and how to include this ichnotaxonomy in the skeleton-based taxonomy. This leads to the establishment of several criteria, e.g. ichnospecies should be defined on the print morphology and the relative position of the prints (including the variability due to the track-maker’s dynamics), two ichnospecies should represent different species, the ichnospecies and ichnogenus levels are sufficient to discriminate the ichnotaxa and link them to the skeleton-based taxonomy. These ichnotaxonomical criteria are applied to a revision of the ichnogenus Pteraichnus Stokes 1957 (Pterosauria, Pterodactyloidea). Only the type species Pteraichnus saltwashensis is considered as valid, the pterosaurian origin of Purbeckopus is questioned and Agadirichnus is highlighted because it could be a senior synonym of Pteraichnus. The result of this drastic revision underlines the importance of the proposed ichnotaxonomical principles to avoid the unfounded proliferation of tetrapod ichnotaxa.