This article requests rejection of the bacterial names Chloropseudomonas and Chloropseudomonas ethylica as nomina rejicienda (rejected names) due to the original descriptions being based on mixed cultures. Chloropseudomonas ethylica was originally proposed as a motile, green photosynthetic bacterium and was validated as a type species. However, published descriptions contained significant inconsistencies: the organism was initially described as nonmotile but later as motile, and cell suspensions appeared green while individual cells were colorless. Examination of strain 2K subcultures revealed the cultures contained two distinct microorganisms: Chlorobium limicola, a nonmotile photosynthetic rod, and Desulfuromonas acetoxidans, a heterotrophic, non-photosynthetic flagellated rod. These two organisms formed a vigorous ecosystem together in Larsen medium. No motile Chlorobiaceae could be isolated from any alleged Chloropseudomonas culture, and no pure cultures matching the original description have been identified since. The author concludes that because legitimate pure cultures of a chloropseudomonad do not exist, both names should be rejected as nomen confusum (confused name).

Key findings

• Chloropseudomonas ethylica cultures were revealed to be mixtures of two distinct bacteria: Chlorobium limicola and Desulfuromonas acetoxidans
• Original descriptions of C. ethylica contained multiple inconsistencies including contradictions about motility and cell coloration
• No pure cultures of a motile Chlorobiaceae matching the original description of C. ethylica could be isolated
• No new isolates identified as chloropseudomonads have been described since Gray et al. demonstrated the mixed-culture nature of C. ethylica