How did the biota of the South American Transition Zone assemble?

Abstract The South American Transition Zone (SATZ) encompasses the Andean highlands from western Venezuela to northern Chile, the desert areas of coastal Peru and northern Chile, and the Monte and Comechingones mountain ranges from central western Argentina. Its biota extends from sea level to ∼4800 m a.s.l. A general theory to explain the biotic assembly of the SATZ is proposed, including the existence of an original Neotropical horobiota; the successive dispersal of the Subantarctic, Patagonian, Central Chilean, and Nearctic cenocrons to it; and the existence of a Recent horobiota. The main events that affected the biotic assembly of the SATZ include: the original isolation of the South American craton and the Patagonian terrane during the Cretaceous–Palaeogene; the uplift of the Andes, which began in the Early Jurassic and occurred gradually from the Late Cretaceous onwards, allowing the passive uplift and vertical colonization of Neotropical taxa and the geodispersal of the Subantarctic, Patagonian, and Central Chilean cenocrons; the development of the Isthmus of Panama, which allowed the geodispersal of the Nearctic cenocron; and the Holocene and Quaternary climatic changes that influenced vegetational changes and provided vicariance events within the different provinces of the SATZ.