Vadaravis brownae was named by Smith et al. (2013) [Vadaravis brownae possesses the following autapomorphies, which are unique among living birds: (1) two (cranial and caudal) small and discrete pneumatopores on the lateral sides of the two caudal-most thoracic centra; and (2) a caudoventrally located pisiform process of the carpometacarpus that projects primarily ventrally and only weakly cranially. In addition to these autapomorphies, Vadaravis brownae can also be diagnosed by the following unique combination of characters: (1) between 12 and 13 synsacral vertebrae; (2) transverse processes of caudal-most synsacral vertebra paddle-shaped in ventral aspect; (3) eight caudal vertebrae (counting the pygostyle as a single element); (4) transverse processes of the caudal vertebrae abruptly disappear in the last free vertebra before the pygostyle; (5) absence of uncinate processes on the thoracic ribs; (6) pneumatic foramina present at the cranial end of the dorsal surface of the sternum, divided medially by a lamina; (7) well-developed ‘balland-socket’ joint between the scapula and coracoid; (8) a spina dorsolateralis ilii that does not extend quite as far caudally as the terminal end of the ischium; and (9) a pons supratendineus that is located in the middle of the distal tibiotarsus. Because Vadaravis is similar in overall size and limb proportions, and known from the same deposits as Presbyornis (Ericson, 2000), a differential diagnosis between the two taxa is warranted, and may aid in the future identification and referral of specimens to Vadaravis. FMNH PA 718 can be distinguished from Presbyornis pervetus Wetmore, 1926, by the following features: (1) posterior thoracic vertebrae less elongate craniocaudally, with two rather than a single pneumatopore; (2) fewer synsacral vertebrae cranial to the cranial end of fossa renalis (section I of Boas, 1934); (3) presence of a recessus caudalis fossa in the ilium; (4) sternal end of coracoid less elongate mediolaterally, and straight rather than weakly concave caudally; (5) coracoid shaft more elongate; (6) tuberculum coracoideum more ventrally placed on proximal scapula; (7) deeper incisure between trabecula lateralis and trabecula intermedia of the sternum (Livezey, 1997); (8) shorter symphysis intermetacarpalis; (9) absence of a preacetabular tuberculum; (10) fusion between the ilia and synsacrum; (11) femur more robust; (12) crista cnemialis lateralis of tibiotarsus convex proximally rather than straight (Ericson, 2000); and (13) distinct distolateral hook in lateral end of crista cnemialis lateralis of tibiotarsus (Ericson, 2000). Vadaravis can be distinguished from the early–middle Eocene stem-threskiornithid Rhynchaeites messelensis Wittich, 1898 (see also Peters, 1983; Mayr, 2002; Mayr and Bertelli, 2011), by the following features: (1) absence of a notarium; (2) facies articularis clavicularis of the coracoid not strongly everted medially; (3) presence of trabecula intermedia on the caudal edge of the sternum; (4) shorter symphysis intermetacarpalis; and (5) much larger size.]. Its type specimen is FMNH PA 718, a partial skeleton (a partial postcranial skeleton including portions of the axial column and associated ribs, sternum, furcula, scapula, coracoid, both humeri, both ulnae, radius,), and it is a 3D body fossil. Its type locality is Fossil Lake Sample Site H-1, which is in a Wasatchian lacustrine - large horizon in the Green River Formation of Wyoming.