1. Paläontologisches Institut und Museum, Universität Zürich, Karl-Schmid-Strasse 4, 8006 Zürich, Switzerland
2. Departamento de Paleontología de Vertebrados, Museo de Historia Natural-Universidad Nacional Mayor de San Marcos, Avenida Arenales 1256, Lima 11, Peru
3. Department of Mammalogy, Natural History Museum of Los Angeles County, 900 Exposition Blvd, Los Angeles, CA 90007, USA
4. Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
5. Dipartimento di Scienze della Terra, Università di Pisa, via Santa Maria 53, 56126 Pisa, Italy