How are Anseriformes related to Galliformes, the chickenlike birds?

Anseriformes (waterfowl) and Galliformes (chickenlike birds) are closely linked and are considered by many scientists to be the oldest assemblage of modern birds. Both orders likely arose from common ancestral forms that were long-legged, unspecialized birds, sharing physical features similar to modern curassows, screamers, and magpie geese.12

Phylogenetic evidence suggests that these two groups represent an ancient lineage, with their ancestors appearing as early as the Cretaceous Period, more than 65 million years ago. While DNA data continue to help researchers resolve the relationships among these major groups, the two orders remain distinct in their modern evolutionary paths—with Anseriformes undergoing significant adaptive radiation into aquatic environments, while Galliformes, such as chickens, turkeys, and pheasants, have maintained their characteristic fowl-like traits.231