Eperythrozoonwenyonii is the correct name if this species is regarded as a separate species (i.e., if its nomenclatural type is not assigned to another species whose name is validly published, legitimate and not rejected and has priority) within a separate genus Eperythrozoon.
The proposal of Neimark et al. (IJSEM 51:897) to reclassify Eperythrozoon wenyoniias "CandidatusMycoplasma wenyonii" is not acceptable; E. wenyonii (AL) would loose standing in nomenclature.Publication:
Neimark H, Johansson KE, Rikihisa Y, Tully JG. Proposal to transfer some members of the genera Haemobartonella and Eperythrozoon to the genus Mycoplasma with descriptions of 'CandidatusMycoplasma haemofelis', 'CandidatusMycoplasma haemomuris', 'CandidatusMycoplasma haemosuis' and 'CandidatusMycoplasma wenyonii'. Int J Syst Evol Microbiol 2001; 51:891-899.
In 2001, Neimark et al. proposed the transfer of Eperythrozoon wenyonii to the genus Mycoplasma with the Candidatus status, "CandidatusMycoplasma wenyonii" Neimark et al. 2001. The Candidatus designation is for new, incompletely described taxa, in order to give them a provisional status; changing validly published names to Candidatus would lose their standing in nomenclature. So, Neimark et al. revise "CandidatusMycoplasma wenyonii" to Mycoplasma wenyonii comb. nov.Publication:
Murray RG, Stackebrandt E. Taxonomic note: implementation of the provisional status Candidatus for incompletely described procaryotes. Int J Syst Bacteriol 1995; 45:186-187.
Strains of Eperythrozoon wenyonii are cell-wall-less uncultivated parasitic bacteria that attach to the surface of host erythrocytes. 16S rRNA gene sequence has been determined for this species and phylogenetic analysis shows that this haemotrophic bacteria is closely related to species in the genus Mycoplasma Nowak 1929 (Approved Lists 1980) [1, 2]. To reflect this phylogenetic affiliation, Neimark et al. 2001  propose that Eperythrozoon wenyonii be transferred to the genus Mycoplasma as "CandidatusMycoplasma wenyonii".Publication:
Anonymous. Notification list. Notification that new names and new combinations have appeared in volume 51, part 3 of the IJSEM. Int J Syst Evol Microbiol 2001; 51:1231-1233.
The full TRBA 466 classification is: risk group = 2, note = "t".