Chimwe chinhu chakadai chinowanikwa mu paleontology, chakagovaniswa nemhuka dzese dziripo (kusanganisira monotremes), asi chisiripo mune chero yekutanga Triassic therapsids, inoratidzwa muMufananidzo 1 (kurudyi), kureva: mhuka dzinoyamwisa dzinoshandisa mapfupa maviri ekunzwa ayo mamwe ese amniotes anoshandisa kudya. Iwo ekutanga amniotes aive nemhino yakabatana yakaumbwa nejoini (ibvi diki kumashure kwehuro yepasi) uye quadrate (ibvi diki kumashure kwehuro yekumusoro). Matetrapods ese asiri emhuka dzinoyamwisa anoshandisa ino sisitimu inosanganisira amphibians, turtles, lizards, nyoka, crocodilians, dinosaurs (kusanganisira mamammosaurs), ichthyosaurs, pterosaurs uye therapsids. Asi mhuka dzinoyamwisa dzine mhino yakasiyana, yakaumbwa chete nejoini yepasi yemhuro (iyo squidry squidry), iyo inoshandiswa nemamwe ese amniotes kuti idye. Nhasi vaKenneth vakaonekwa.
mazino (pamuzasi petsaya, inotakura mazino) uye squamosal