Long overdue extinction of the Protopinaceae

In 1917 the German fossil palaeobotanist Richard Kräusel proposed a new plant family, the Protopinaceae. This family was based on an anatomical feature (mixed type of radial pitting) observed in the secondary xylem of some Mesozoic gymnosperms. Kräusel's hypothesis was that the Protopinaceae had great phylogenetic significance, being an evolutionary link between Palaeozoic and modern conifers. Since their inception the Protopinaceae have been a matter of several controversies. We examine here evidence accumulated in recent years and question the continued existence of this taxon. Not only is the taxonomic status dubious, but it is also no longer tenable that it represents a phylogenetically significant group. We recommend that the Protopinaceae, in name and concept, be put to rest before its 100th anniversary. •Several fossil wood anatomy studies refer to the Protopinaceae.•This “family” is supposed since Kräusel to have evolutionary significance.•Its existence is not supported, however, neither taxonomically nor nomenclaturally.•The Protopinaceae plants are extinct and the classification should also become extinct.