Ku-biology, i-gill arch ibhekisela esakhiweni samathambo esitholakala ezinhlanzini nakwezinye izilwane zasemanzini ezisekela ama-gill. Ama-gill arches ngokuvamile ahlelwa ngababili nhlangothi zombili zomzimba wesilwane futhi anesibopho sokuhlinzeka ngosizo lwesakhiwo kumagill, asetshenziselwa ukuphefumula. Ama-gill arches akhiwe ngochungechunge lwamathambo noma uqwanga oluxhumene nogebhezi lwekhanda noma umgogodla wesilwane futhi lumbozwe ulwelwesi oluncane oluqukethe imithambo yegazi nezinye izakhiwo ezidingekayo ukuze uphefumule.