|O. Lambert et al. 2017||Brujadelphis ankylorostris differs from all other delphinidans except Isthminia Pyenson etal., 2015 in the partial ankylosis of the considerably thickened premaxillae above the mesorostral groove. It further differs from all other delphinidans except Atocetus and to a lesser extent Pithanodelphis Abel, 1905 in the inflated nasals with a transversely convex dorsal surface, from all other delphinidans except Parapontoporia Barnes, 1984 and to a lesser extent Isthminia in the longitudinally extended crest formed by the strongly transversely pinched frontals on the vertex, from all other delphinidans except several inioids and phocoenids in the presence of premaxillary eminences instead of premaxillary sac fossae, and from all other delphinidans except several archaic Miocene delphinidans including Atocetus, Isthminia Pithanodelphis and part of the pontoporiids in the presence of an internasal fossa. Brujadelphis ankylorostris further differs from Isthminia in the tooth count being markedly higher and in lacking the Z-shaped pattern of the posterolateral and posteromedial sulci.
It differs from many archaic Miocene delphinidans including Atocetus, Delphinodon Leidy, 1869, Kentriodon, Macrokentriodon Dawson, 1996 and Pithanodelphis in the absence of a contact between premaxilla and nasal. It differs from the lipotids Lipotes and Parapontoporia in the absence of an anterior bullar facet, from Inia and pontoporiids in the proportionally longer anterior process of the peri- otic, from pontoporiids in lacking a concave dorsal outline of the posterior process of the periotic, from iniids in the lack of a frontal boss and from Inia in lacking developed heels on crowns of posteriormost teeth.