"Type IV [of the Octopus vulgaris species complex] occurs in subtropical to temperate eastern Asia. Octopus jollyorum Reid & Wilson, 2015 was described based on a phylogenetic analysis that included ‘O. vulgaris’ individuals sampled throughout its known range and the discovery of a member of the group in the Kermadec Islands. Octopus jollyorum was used to recognise a clade that included specimens from Japan and Taiwan, as no type specimen existed for a potential available name, O. sinensis. Subsequently, Gleadall (2016) designated a neotype for O. sinensis. While not stated in Gleadall (2016), we now recognise O. jollyorum as a junior synonym of O. sinensis and the latter name is used for representatives of this clade in the current study.

"Previous molecular‐based phylogenetic analyses using five mitochondrial genes placed Chinese and Japanese O. vulgaris into a well‐supported monophyletic clade, distinct from all other members of the species complex (Amor et al. 2014). Reid & Wilson (2015) considered mitochondrial‐based differences to warrant the distinction of Kermadec Island individuals from O. vulgaris s. s., establishing the name O. jollyorum for this clade, which also encompassed Asian Type IV O. vulgaris individuals. The recent designation of a neotype for O. sinensis effectively renames the clade member taxa and places O. jollyorum in synonymy with O. sinensis. We formally synonymise the two species here. The latter species was redescribed by Gleadall (2016) and can be distinguished from O. vulgaris with the former species having shorter arms and fewer suckers. Although individuals from Asia and the Kermadec Islands are currently understood to comprise a single species, the substantial geographic distance between these two geographic regions warrants further investigation into their species‐level diversity."