Some pedal phalanges and a trochleae of tarsometatarsus were also referred to the type, but they haven't been described in detail. These fossils were found in the lower Miocene Monte León Formation, one of the two formations the taxon is definitively known from. Some additional fossils, including a quadrate, were referred to Brontornis by Moreno & Mercerart in 1891, but these were dubiously referred.
Some pedal bones and tarsometatarsus elements were initially assigned to the type, but they haven't been fully described. These fossils were found in the lower Miocene Monte León Formation, one of two formations where this taxon is definitively known from.  Additionally, some other fossils, including a quadrate bone, were tentatively attributed to Brontornis by Moreno & Mercerart in 1891, but their classification remains uncertain.