Complex sentence: The first scientific defence of humanity originating in South America came from the Argentine paleontologist Florentino Ameghino in 1880, who published his research in "La antigüedad del hombre en el Plata".
Split into simpler sentences: The first scientific defence of humanity originating in South America came from the Argentine paleontologist Florentino Ameghino in 1880. Ameghino published his research in a book titled "La antigüedad del hombre en el Plata".