User blog comment:Adsper/All Possible Mobs/@comment-29412454-20180809081228/@comment-2605:A000:A487:4C00:E6:57C3:F689:A3D3-20180826153237

It probably will be sauropelta

https://www.minecraftforum.net/forums/mapping-and-modding-java-edition/minecraft-mods/wip-mods/1442049-fossil-archeology-content-pack-extinct