José Fernando Bonaparte (14 June 1928 – 18 February 2020) was an Argentine paleontologist who discovered a plethora of South American dinosaurs and mentored a new generation of Argentine paleontologists. One of the best-known Argentine paleontologists, he has been described by paleontologist Peter Dodson as "almost singlehandedly ... responsible for Argentina becoming the sixth country in the world in kinds of dinosaurs". Biography Bonaparte was the son of an Italian sailor, with no close connection to Napoleon's House of Bonaparte. He was born in Rosario, Santa Fe, Argentina, and grew up in Mercedes, Buenos Aires. Despite a lack of formal training in paleontology, he started collecting fossils with many friends at an early age, and created a museum in their home town. He later became the curator of the National University of Tucumán, where he was named Doctor Honoris causa in 1976, and then in the late 1970s became a senior scientist at the Museo Argentino de Ciencias Naturales in Buenos Aires. Bonaparte was a two-time Guggenheim Fellow and since the 1970s received periodic funding from the National Geographic Society. He was reportedly hard-working, stubborn, and had a strong personality, even violent. He received another honorary degree from the National University of Comahue in 2011. Bonaparte died at dawn in his sleep on 18 February 2020 at age 91. Career Discovery of southern diversity Between 1975 and 1977, Bonaparte worked on excavation of the Saltasaurus dinosaur with Martín Vince and Juan C. Leal at the Estancia "El Brete". This find was in 1977 reported in the scientific literature. With fellow-Argentine Jaime Powell, Bonaparte studied the Saltasaurus and discovered that it had armoured plates, known as osteoderms, embedded in its skin. Based on this discovery, together with twenty examples of Kritosaurus australis and a lambeosaurine dinosaur found in South America, Bonaparte hypothesized that there had been a large-scale migration of species between the Americas at the end of the Mesozoic period. The supercontinent of Pangea split into Laurasia in the north and Gondwana in the south during the Jurassic. During the Cretaceous, South America pulled away from the rest of Gondwana. The division caused a divergence between the northern biota and the southern biota, and the southern animals appear strange to those used to the more northerly fauna. Bonaparte's finds illustrate this divergence, and caused palaeontologist Robert Bakker to dub him the "Master of the Mesozoic". Discoveries Bonaparte discovered an array