The discovery of a new fossil 2005, Onychonycteris finneyi, analyzed by the team of Nancy Simmons, has revived debates about the appearance of echolocation and flight . During this congress, Nancy Simmons defended his hypothèse du flight-first, the appearance of the flight before echolocation .
Hata hivyo, Utafiti wa fossils ni mkubwa kujifunza zaidi juu ya asili ya popo ikiwa ni pamoja na mageuzi ya echolocation na kukimbia. ugunduzi wa mafuta mpya 2005, Onychonycteris finneyi, kuchambuliwa na timu ya Nancy Simmons, ina ilifufuka mijadala kuhusu kuonekana ya echolocation na kukimbia.