Objection to the proposition of the new genus Abyssivirga

Abstract : We have read with interest the recent paper published by Schouw et al. [1] in IJSEM (Vol 66, pp. 1724–1734) entitled: 'Abyssivirga alkaniphila gen. nov., sp. nov., an alkane-degrading, anaerobic bacterium from a deep-sea hydrother-mal vent system, and emended descriptions of Natranaero-virga pectinivora and Natranaerovirga hydrolytica'. We disagree with the proposal of Abyssivirga as a new genus due to phylogenetic considerations as shown below. Indeed, we noticed that a BLAST analysis of the Abyssivirga alkani-phila 16S rRNA gene sequence indicated 99.4 % similarity with Vallitalea guaymasensis isolated from sediments of the Guaymas Basin, and 96.1 % with Vallitalea pronyensis isolated from a hydrothermal chimney in Prony Bay. Both Val-litalea species have been fully characterized in IJSEM [2, 3]. Based on phylogenetic analyses, we believe that the proposal of the new genus Abyssivirga should be reconsidered. A. alka-niphila should be reassigned to the genus Vallitalea, and possibly as a novel species, 'Vallitalea alkaniphila', if demonstrated by significant DNA–DNA hybridization and phenotypic differences. With the aim to clearly establish the phylogenetic position of A. alkaniphila and its effective affiliation to the genus Vallitalea, a phylogenetic tree is reconstructed here (Fig. 1).