A third rarer type of feather, the filoplume, is hairlike and (if present in a bird; they are entirely absent in ratites citation ) grows along the fluffy down feathers. Source: Internet
However, the classification of the ratites as a single order has always been questioned, with the alternative classification restricting the Struthioniformes to the ostrich lineage and elevating the other groups. Source: Internet
Illustration of cassowary skull The evolutionary history of cassowaries, as of all ratites, is not well known. Source: Internet
In the Berlin specimen, there are "trousers" of well-developed feathers on the legs; some of these feathers seem to have a basic contour feather structure, but are somewhat decomposed (they lack barbicels as in ratites ). Source: Internet
It is the only structure found in primitive birds such as ratites. Source: Internet
Like most other ratites, they have no uropygial gland (preen gland). Source: Internet