Kuwanikwa kweCastorocauda lutrasimilis chiratidzo chekutanga chekuti hama yepedyo yezvipembenene yakashandiswa mumvura dinosaurs vasati varasikirwa nehutongi makore mamiriyoni makumi matanhatu nematanhatu apfuura, vachisundira kumashure zuva rinofungidzirwa rehama dzezvipembenene dzakashandiswa kune mararamiro e-aquatic ne 110 mamiriyoni emakore. Zvichibva pane fossils anozivikanwa iye zvino, mutsara wezvipembenene haungaone imwe semi-aquatic fomu inoshanduka kusvikira kuEocene. Nemhaka yokuti zvishoma zvisaririra zvakasara zvakawanikwa, zvaimbofungidzirwa kuti, kusvikira kuCretaceous <unk> Paleogene muganhu (K<unk>Pg muganhu), zvipembenene zvose zvaive zviduku, pasi-zvinogara kana miti-zvinogara, mhuka dzeusiku dzakafanana nemashrews, hedgehows, treeshrews, kana tenrecs.
Eocene