ACKNOWLEDGMENTS
C. Norris, D. Brinkman, and M. Fox from Yale Peabody Museum (New Haven), and M. L. Taglioretti and F. Scaglia from the Museo Tradicional Lorenzo Scaglia (Mar del Plata) allowed and facilitated the consult of the fossil collections under their management. AMNH ornithological collection staff, and L. Witmer are thanked for allowing access to extant Cathartiformes specimens. C. P. Tambussi is thanked for useful suggestions on an early draft of the manuscript. Editor V. De Pietri, Technical Editor B. Haiar, A. Louchart and two anonymous reviewers are thanked for providing helpful feedback on the manuscript. I am grateful to CONICET for permanent support. This work was supported by PICT 2014-2330, and PUE 2016-CONICET-CICTERRA.