From the mid-Eocene onwards – about 45 Mya or so, true galliforms are known, and these completely replace their older relatives in the early Neogene. Since the earliest representatives of living galliform families apparently belong to the Phasianidae – the youngest family of galliforms, the other families of Galliformes must be at least of Early Eocene origin but might even be as old as the Late Cretaceous. The ichnotaxon "Tristraguloolithus cracioides" is based on fossil eggshell fragments from the Late Cretaceous Oldman Formation of southern Alberta, Canada, which are similar to chachalaca eggs, but in the absence of bone material, their relationships cannot be determined except that they are apparently avian in origin.