This order comprises just one family, Steatornithidae, with only a single species, Steatornis caripensis (Oilbird).
Mayr, G. (2014), A hoatzin fossil from the middle Miocene of Kenya documents the past occurrence of modern-type Opisthocomiformes in Africa, Auk 131,
Mayr, G., and V.L. De Pietri (2014), Earliest and first Northern Hemispheric hoatzin fossils substantiate Old World origin of a "Neotropic endemic",
Naturwissenschaften 101, 143-148. (abstract)