Is the American bullfrog Rana catesbeiana or Lithobates catesbeianus?
The simple answer is "It's both!" In taxonomic terms, Rana catesbeiana = Lithobates catesbeianus because both scientific names have been assigned to the same species. Therefore, it is correct to use either Rana catesbeiana or Lithobates catesbeianus, or in combination such as Rana (Lithobates) catesbeiana. Incidentally, another legitimate synonym is, Aquarana catesbeiana.
The Latin name Rana catesbeiana has been around for a long time, so any literature that predates 2006 will likely use this scientific name. However, a multi-authored paper published in 2006 looked broadly at the phylolgenetic relationships in the Class Amphibia and determined that the genus Rana was a conglomeration of many genera. Their recommendation was to move the American bullfrog and its closest relatives from Rana into the genus Lithobates. This taxonomic reassignment may last or it may not as the results from more refined investigations of the family Ranidae emerge. But for now, all you need to know is that references to the American bullfrog may refer to either Rana or Lithobates and both are correct.
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