Duba wurin da ke ƙasa sannan ka amsa tambayar daga baya a cikin harshe ɗaya kamar yadda wurin yake:  Passage: Gano Castorocauda lutrasimilis shine alama ta farko da ke nuna cewa dangi na dabbobi masu shayarwa sun dace da ruwa kafin dinosaur ya rasa rinjaye shekaru miliyan 66 da suka gabata, yana turawa baya kwanan wata da aka kiyasta don dangi masu shayarwa sun dace da salon rayuwa na rabin ruwa da shekaru miliyan 110. Dangane da burbushin halittu da aka sani a halin yanzu, layin dabbobi masu shayarwa ba zai ga wani nau'in ruwa mai ruwa ya samo asali ba har zuwa Eocene. Saboda 'yan burbushin da aka gano, an yi tunanin cewa, har zuwa iyakar Cretaceous<unk>Paleogene (K<unk>Pg iyaka), dukkan dabbobi masu shayarwa sun kasance ƙananan, masu zama a ƙasa ko masu zama a cikin bishiyoyi, dabbobi masu rai na dare kamar su shrews, hedgehogs, treeshrews, ko tenrecs. Wannan ra'ayi yanzu ya zama ƙarya ta hanyar armadillo-kamar Fruitafossor, da dinosaur-cin Repenomamus, da squirrel-kamar Volaticotherium mai tashi, da karami da ƙyallen tenrec-kamar halittar da ake kira Spinolestes kuma yanzu Castorocauda mai kama da beaver.  Tambaya: Me ya sa aka taɓa tunanin cewa dabbobi masu shayarwa ƙanana ne da suke zama a ƙasa ko kuma itatuwa?
an sami 'yan burbushin da aka gano