The nomenclatural type of the genus Methanocorpusculum Zellner et al. 1988 and the selection of the correct name

A recent Request for an Opinion has raised the issue of the inter-relationship between Methanocorpusculum parvum Zellner et al. 1988, the type species of the genus Methanocorpusculum Zellner et al. 1988 as defined at the time of valid publication of the genus name and the subsequent recognition of Methanocorpusculum aggregans (Ollivier et al., 1985) Xun et al.1989 as an earlier heterotypic synonym. Examination of the relevant literature indicates that there are a number of misunderstandings that have arisen. In particular misinterpretation of Rule 15 of the International Code of Nomenclature of Prokaryotes continues to be a source of confusion. Additional problems centre on whether the nomenclatural type of a taxon continues to be the nomenclatural type even if that name is not treated as the correct name and would not appear in a list of names in a given classification. It would be appropriate to clarify these issues.