DNA RELATEDNESS AMONG NONPIGMENTED SPECIES OF ALTEROMONAS AND SYNONYMY OF ALTEROMONAS-HALOPLANKTIS (ZOBELL AND UPHAM 1944) REICHELT AND BAUMANN 1973 AND ALTEROMONAS-TETRAODONIS SIMIDU ET-AL 1990

The taxonomic relationships among nonpigmented species of the genus Alteromonas were assess DNA-DNA hybridization. The species formed two groups based on DNA homology values and moles percent G+C of DNA: Alteromonas macleodii, the type species, had a moles percent G+C content 4 to 7% higher than those of the other group, and it had less than 5% DNA homology to the second group formed by the remaining species. The remaining species formed seven DNA homology subgroups, of which five corresponded to the type strains of A. atlantica, A. espejiana, A. carrageenovora, A. undina, and A. nigrifaciens. A sixth subgroup included the type strains of A. haloplanktis and A. tetraodonis, which showed hybridizations of more than 80%. The species in the second group were related to each other at the genus level, but a nomenclatural proposal is postponed. The hybridization data showed that the name A. tetraodonis Simidu et al. 1990 should be recognized as a junior subjective synomyn of A. haloplanktis (ZoBell and Upham 1944) Reichelt and Baumann 1973. The seventh subgroup included two as yet unassigned strains which were misidentified as to species.