Corynebacterium megadyptis sp. nov. with two subspecies, Corynebacterium megadyptis subsp. megadyptis subsp. nov. and Corynebacterium megadyptis subsp. dunedinense subsp. nov. isolated from yellow- eyed penguins

Novel Corynebacterium strains, 3B(T) and 7B(T), were isolated from the oral cavities of young chicks of yellow -eyed penguins (hoiho), Megadyptes antipodes. A polyphasic taxonomic characterization of these strains revealed chemotaxonomic, biochemical and mor-phological features that are consistent with those of the genus Corynebacterium. The 16S rRNA gene sequence similarity values between the strains and their closest phylogenetic neighbour, Corynebacterium ciconiae CCUG 47525(T) were 99.07 %, values that are in line with their phylogenomic positions within the evolutionary radiation of the genus Corynebacterium. Digital DNA-DNA hybridization values and average nucleotide identities between the genome sequences of the two strains and related Corynebacte-rium species were well below the defined threshold values (70 and 95-96 %, respectively) for prokaryotic species delineation. The genome size of these strains varied between 2.45-2.46 Mb with G+C content 62.7-62.9 mol%. Strains 3BT and 7B(T) were Gram -stain positive bacilli that were able to grow in presence of 0-10 % (w/v) NaCl and at temperature ranging between 20-37?. The major fatty acids (>15 %) were C(16:0 )and C-18: 1 ?9c, and the mycolic acid profile included 32-36 carbon atoms. We propose that these strains represent a novel species, Corynebacterium megadyptis sp. nov. with 3B(T) (=DSM 111184(T)=NZRM 4755(T)) as the type strain. Phylog-enomically, strains 3B(T) and 7B(T) belong to two lineages with subtle differences in MALDI- TOF spectra, chemotaxonomic profiles and phenotypic properties. The fatty acid profile of strain 3B(T) contains C-18: 0 as a predominant type (>15 %), which is a minor component in strain 7B(T). Strain 7B(T) can oxidize N-acetyl-o-glucosamine, l-serine, a-hydroxy-butyric acid, l-malic acid, l- glutamic acid, bromo-succinic acid and l -lactic acid, characteristics not observed in strain 3B(T). Therefore, we propose that these strains represent two subspecies, namely Corynebacterium megadyptis subsp. megadyptis subsp. nov. (type strain, 3B(T)=DSM 111184(T)=NZRM 4755(T)) and Corynebacterium megadyptis subsp. dunedinense subsp. nov. (type strain, 7B(T)=DSM 111183(T)=NZRM 4756(T)).