Arachnia propionica (Buchanan and Pine 1962) Pine and Georg 1969 (Approved Lists 1980), Propionibacterium propionicum corrig. (Buchanan and Pine 1962) Charfreitag et al. 1988 and Pseudopropionibacterium propionicum (Buchanan and Pine 1962) Scholz and Kilian 2016 and the nomenclatural consequences of changes in the taxonomy of the genus Propionibacterium.

In a recent publication dealing with the classification of species assigned to the genus Propionibacterium, evidence was presented supporting that it would be appropriate to sub-divide the genus into four genera, Propionibacterium Orla-Jensen 1909 (Approved Lists 1980) emend. Scholz and Kilian 2016, Acidipropionibacterium Scholz and Kilian 2016, Cutibacterium Scholz and Kilian 2016 and Pseudopropionibacterium Scholz and Kilian 2016. Of these genera, Pseudopropionibacterium Scholz and Kilian 2016 was proposed to contain a single species Pseudopropionibacterium propionicum (Buchanan and Pine 1962) Scholz and Kilian 2016 that is also the nomenclatural type. The nomenclatural type of Pseudopropionibacterium propionicum (Buchanan and Pine 1962) Scholz and Kilian 2016 is also the nomenclatural type of Propionibacterium propionicum corrig. (Buchanan and Pine 1962) Charfreitag et al. 1988 and Arachnia propionica (Buchanan and Pine 1962) [Pine and Georg 1969 (Approved Lists 1980)] and are consequently homotypic synonyms. Arachnia propionica(Buchanan and Pine 1962) Pine and Georg 1969 (Approved Lists 1980) was the nomenclatural type and only species placed within the genus Arachnia Pine and Georg 1969 (Approved Lists 1980). In the light of this fact, the consequences for the names Arachnia propionica (Buchanan and Pine 1962) Pine and Georg 1969 (Approved Lists 1980), Propionibacterium propionicum corrig. (Buchanan and Pine 1962) Charfreitag et al. 1988 and Pseudopropionibacterium propionicum(Buchanan and Pine 1962) Scholz and Kilian 2016 are discussed together with the correct name for the recently validly published name Pseudopropionibacterium rubrum Saito et al. 2018.