Croceivirga litoralis sp. nov., isolated from coastal surface water, and reclassification of Muricauda lutea as Croceivirga lutea comb. nov

Proposal of Allomuricauda gen. nov. and Allofranklinella gen. nov. as replacement names for the illegitimate prokaryotic generic names Muricauda and Franklinella, respectively

The prokaryotic generic names Muricauda Bruns et al. 2001 and Franklinella Bernard et al. 2022 are illegitimate because they are later homonyms of the genus names Muricauda Small 1903 (synonym of Arisaema; Tracheophyta - Liliopsida - Araceae) and Franklinella Stewart and Hendrix 1945 (a Devonian ostracod genus) and Franklinella Lenz 1973 (a Devonian brachiopod genus), respectively (Principle 2 and Rule 51b(4) of the International Code of Nomenclature of Prokaryotes). We therefore propose the replacement generic names Allomuricauda and Allofranklinella, with type species Allomuricauda ruestringensis and Allofrankinella schreckenbergeri, respectively.

Muricauda okinawensis sp. Nov. and Muricauda yonaguniensis sp. Nov., Two Marine Bacteria Isolated from the Sediment Core near Hydrothermal Fields of Southern Okinawa Trough

Two strains, 81s02^T and 334s03^T, were isolated from the sediment core near the hydrothermal field of southern Okinawa Trough. The cells of both strains were observed to be rod-shaped, non-gliding, Gram-staining negative, yellow-pigmented, facultatively anaerobic, catalase and oxidase positive, and showing optimum growth at 30 °C and pH 7.5. The strains 81s02^T and 334s03^T were able to tolerate up to 10% and 9% (w/v) NaCl concentration, respectively. Based on phylogenomic analysis, the average nucleotide identity (ANI) and the digital DNA-DNA hybridization (dDDH) values between the two strains and the nearest phylogenetic neighbors of the genus Muricauda were in range of 78.0-86.3% and 21.5-33.9%, respectively. The strains 81s02^T and 334s03^T shared 98.1% 16S rRNA gene sequence similarity to each other but were identified as two distinct species based on 81.4-81.5% ANIb, 85.5-85.6% ANIm and 25.4% dDDH values calculated using whole genome sequences. The strains 81s02^T and 334s03^T shared the highest 16S rRNA gene sequence similarity to M. lutimaris SMK-108^T (98.7%) and M. aurea BC31-1-A7^T (98.8%), respectively. The major fatty acid of strains 81s02^T and 334s03^T were identified similarly as iso-C_15:0, iso-C_17:0 3-OH and iso-C_15:1 G, and the major polar lipids of the both strains consisted of phosphatidylethanolamine and two unidentified lipids. The strains contained MK-6 as their predominant menaquinone. The genomic G+C contents of strains 81s02^T and 334s03^T were determined to be 41.6 and 41.9 mol%, respectively. Based on the phylogenetic and phenotypic characteristics, both strains are considered to represent two novel species of the genus Muricauda, and the names Muricauda okinawensis sp. nov. and Muricauda yonaguniensis sp. nov. are proposed for strains 81s02^T (=KCTC 92889^T = MCCC 1K08502^T) and 334s03^T (=KCTC 92890^T = MCCC 1K08503^T).

Identification and classification of Croceivirga thetidis sp. nov., a marine Flavobacteriaceae isolated from the hard coral Acropora

A taxonomic investigation using a polyphasic method was conducted to identify a novel marine flavobacterium, designated as DJ-13^T, isolated from the hard coral Acropora sp. collected at Okinawa, Japan. Bacterial cells were Gram-stain-negative, yellow-colored, strictly aerobic, rod-shaped, catalase- and oxidase-positive, non-motile, and chemoorganoheterotrophic. The novel isolate grew at NaCl concentrations of 0.5-7%, pH 6.5-9.0, and 15-37 °C. A phylogenetic study on the basis of the 16S rRNA gene sequence revealed that strain DJ-13^T belongs to the family Flavobacteriaceae and that it shared the greatest sequence similarity (95.9%) with Croceivirga lutea CSW06^T. Strain DJ-13^T comprised iso-C17:0 3-OH, iso-C15:0, and iso-C15:1 G as the main (> 10%) cellular fatty acids. Menaquinone-6 (MK-6) was the only respiratory quinone. The assembled draft genome size of strain DJ-13^T was 3.71 Mbp with G + C content of 38.7 mol%. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and average amino acid identity (AAI) values of DJ-13^T and the species of the genus Croceivirga were found to be 74.9-75.5%, 13.4-14.7%, and 68.2-72.4%, respectively. Strain DJ-13^T contained phosphatidylethanolamine, two unidentified aminolipids, and five unidentified lipids as polar lipids. From the polyphasic taxonomic results presented, the strain is considered to represent a novel species of the genus Croceivirga for which the name Croceivirga thetidis sp. nov. is proposed. The type strain of C. thetidis sp. nov. is DJ-13^T (= KCTC 72790^T = NBRC 114252^T).