Why the Long Face? Kangaroos and Wallabies Follow the Same ‘Rule’ of Cranial Evolutionary Allometry (CREA) as Placentals

Among closely related species, larger mammals tend to have a longer face and proportionally smaller braincase. This putative ‘rule’ in mammalian macroevolution has been proposed for the first time in 2013 based on 3D geometric morphometrics of antelopes, fruit bats, tree squirrels and mongooses. To firmly demonstrate that this trend holds as a ‘rule’ requires expanding the analysis in more lineages and other mammalian orders: if supported in...