Ardipithecus ramidus and ardipithecus kadabba have defied expectations about early hominins because

Ardipithecus ramidus and Ardipithecus kadabba have defied expectations about early hominins because: Both lived in densely forested environments
Due to its structure, researchers expected early hominins incapable to live in an environment with large trees. They expected them to live on an open field such as grassland.