Abstract: Analysis of little-known manuscripts revealed that there have been at least two pre-Linnean descriptions of the South American freshwater dolphin lnia geoffrensis (Blainville, 1817). The earliest one that we found was made by Frei Cristbvao de Lisboa in a manuscript written around 1627. The second one was by Pehr Lofling, a disciple of Linnaeus, who wrote a very detailed and accurate description of this mammal in 1755. He used the binomial system to designate this species, and his description was much more complete and sophisticated than the ones used by Linnaeus in the 10th edition of Systema Naturae for other cetaceans. This and other zoological work by Lofling re- mains almost completely unexamined to date. Like the outcome of other field work carried out by many Spanish scientists in America, failure to publish the findings of the expeditions resulted in scientific information being largely lost.