 A closely related genus, "Aiolornis", was about 40% larger and lived at an earlier time; it was formerly known as "Teratornis incredibilis", but is distinct enough to be placed in its own genus.The finger bones are fused as in all modern birds; however, part of the index finger forms a shelf which aided in bearing the load of long and stout primaries, which enabled the bird to utilize strong upcurrents.The legs were similar to an Andean Condor's, but stouter, and the feet could hold prey items for tearing off pieces, but could not exert a very forceful grip such as in birds of prey.