Sandgrouse and buttonquail
Pin-tailed sandgrouse and Pallas's sandgrouse, and the Painted buttonquail.
Goura cristata, Pterocles alchata and Syrrhaptes paradoxus skeletons.
Recently classified in the Columbiformes group at present are the sand grouse, (previously classed as Galliformes along with other grouse), most closely related the the Mesites - flightless birds of Madagascar, which may also be closely related to the Kagu and Sun Bittern.
The Painted buttonquail is an Australian bird that looks similar to but is only distantly related to quail. Currently it is thought to be a relative of Charadriiformes (waders, gulls and auks). It is included here as an oddball for anatomical comparison.
Courtesy of the University Museum of Zoology, Cambridge