Waa kuwee kuwan hoos ku qoran oo aan ahayn koox xayawaan ah: Iagerstatten, cnidarians ama cypdippids? Marka la eego su'aasha hore, ku qor macnaha guud ee jawaabta. Waxay noqon kartaa 1 ilaa 20 jumladood. Macnaha guud:
Inkastoo jirkooda uu ahaa mid jilicsan oo jilicsan, hadana waxa la rumeysan yahay in ay matalayeen ctenophores, oo aan lahayn wax laalaab ah balse leh fara badan oo ka badan qaababka casriga ah, waxaa laga helay lagerstätten tan iyo Cambrian hore, qiyaastii 515 milyan oo sano ka hor. Mawqifka ctenophores ee geedka hidda-wadaha ee xayawaanka ayaa muddo dheer laga doodayay, aragtida ugu badan ee hadda jirta, oo ku saleysan hidda-wadaha molecular, ayaa ah in cnidarians iyo bilaterians ay aad ugu dhow yihiin midba midka kale marka loo eego ctenophores. Falanqayn dhowaan lagu sameeyay molecule phylogenetics ayaa lagu soo gabagabeeyay in awoowe guud ee dhammaan ctenophores-yada casriga ahi uu ahaa mid u eg cydippid, iyo in dhammaan kooxaha casriga ahi ay soo muuqdeen dhowaan, laga yaabee inay ka dambeeyeen dhacdadii dabar go'a Cretaceous <unk> Paleogene 66 milyan oo sano ka hor. Caddaymaha la ururiyey tan iyo 1980-meeyadii waxay muujinayaan in "cydippids" aysan ahayn monophyletic, si kale haddii loo dhigo kuma jiraan dhammaan oo kaliya farackii hal awoowe oo caadi ah, maxaa yeelay dhammaan kooxaha kale ee caadiga ah ee ctenophore waa farac ka yimid cydippids kala duwan.